To see the other types of publications on this topic, follow the link: Axial stress-strain curve.
Journal articles on the topic 'Axial stress-strain curve'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Axial stress-strain curve.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Huo, Hong Yuan, Chen Jie Cao, Li Sun, Li Sha Song, and Tong Xing. "Experimental Study on Full Stress-Strain Curve of SFRC in Axial Tension." Applied Mechanics and Materials 238 (November 2012): 41–45. http://dx.doi.org/10.4028/www.scientific.net/amm.238.41.
Full textAbstract:
The tests were carried out to study the effects of the fraction of steel fiber by volume and the thickness of cement paste wrapping steel fibers on the axial tensile properties of steel fiber reinforced concrete (SFRC). The strength grade of SFRC was CF40 with the fraction of steel fiber by volume varying from 0.5% to 2.0%, and the thickness of cement paste wrapping steel fibers varying from 0.8mm to 1.2mm. The tests were conducted by WAW-600 electric-hydraulic servo-type test machine. The results show that the axial tensile properties such as the axial tensile strength, the fullness of stress-strain curve, the tensile energy and the axial tensile toughness ratio are all improved obviously by the adding of steel fiber in concrete. The reasonable thickness of cement paste wrapping steel fibers is 1.0mm. The formulas for stress-strain relationship of SFRC in axial tension are proposed.
2
Sun, Lin Zhu, Tie Cheng Wang, and Fang Yang. "Stress-Strain Model for Confined Concrete in Cross-Shaped Columns." Advanced Materials Research 450-451 (January 2012): 822–26. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.822.
Full textAbstract:
To establish complete stress-strain curve equations for confined concrete in cross-shaped columns, we designed 7 test specimens corresponding to the usable eigenvalue range of stirrup of the cross-shaped columns. We obtained the test results of the reinforced concrete cross-shaped columns through axial compression test, got the system parameters of a stress-strain model through statistical analysis of the test data, and then established stress-strain curves for confined concrete in the cross-shaped columns. This model reflects the variation rule of the stress-strain curve of confined concrete in cross-shaped columns. Compared with the stress-strain model for confined concrete in square columns, the confined concrete in cross-shaped columns has smaller peak stress, larger peak strain, and relatively steeper descending part of curve. The research results provide theorotical basis for nonlinear analysis of cross-shaped columns.
3
Sun, Ming Quan, and Shi Feng Yang. "The Study of Cemented Sand and Gravel Constitutive Model." Advanced Materials Research 243-249 (May 2011): 4596–601. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4596.
Full textAbstract:
Basing on triaxial experiments, the paper conducts the research to Cemented Sand and Gravel constitutive model. Using virtual rigid spring method, the Cemented Sand and Gravel constitutive model with considering the softening characteristics of material is established, and parameters needed are determined, the model establishes the foundation of non-linear analysis of Cemented Sand and Gravel structure. Mechanical properties and constitutive model study of Cemented Sand and Gravel is key to Cemented Sand and Gravel faced eath-rockfill dam. Basing the Mechanical properties triaxial experiment of the material, the paper gives further discussion on the constitutive model of Cemented Sand and Gravel. From the results of the triaxial test, when the cemented material content is smaller than 20kg/m3, the stress strain curve agrees quite well with hyperbolic law to which the normal gravel test curve also obeys, the exception is the increase of shearing strength. If the cemented material content is more than 30kg/m3, there is a peak value on the stress strain curve, the curve (before peak value) shows that axial strain increase with deviatoric stress with the increment gradually changing slowly, i.e. the stress strain curve has obvious nonlinear feature. the curve peaks value at the axial strain =2％, the stress strain curve present softening pattern that deviatoric stress decreases with the strain increase if continuous applying axial load. When axial strain lies between 2% and 6%, the shearing strength of samples decreases rapidly, after this interval, the shear strength tends to the stable value in the final. It is core problem the paper try to solve that how to describe Cemented Sand and Gravel constitutive model.
4
Lade, Poul V., and Hamid Karimpour. "Stress relaxation behavior in Virginia Beach sand." Canadian Geotechnical Journal 52, no. 7 (July 2015): 813–35. http://dx.doi.org/10.1139/cgj-2013-0463.
Full textAbstract:
Effects of strain rate on the stress–strain and subsequent stress relaxation behaviors have been studied by performing triaxial compression tests on dense Virginia Beach sand specimens at three different strain rates (ratio of 256 between the slowest and the fastest) under low and high confining pressures. For the tests performed under low confining pressure, the specimens that were initially sheared at a faster rate showed a slightly higher amount of stress relaxation, but almost identical stress–strain behaviors were achieved. For tests performed under high confining pressure, the same amount of strength was achieved at high axial strains (10% to 20%), but specimens sheared at higher strain rates showed a slightly stiffer stress–strain response at low axial strains (up to 10%). Similar to the tests performed under low confining pressure, higher strain rates produced higher amounts of stress relaxation to some extent. Effects of correction of axial strain due to load cell expansion and drainage condition during stress relaxation have also been studied and the results indicated that correction of axial strain and undrained condition will both increase the observed amount of stress relaxation. Moreover, a 1 day stress relaxation curve was obtained by connecting the ending stress–strain points of six stress relaxation tests initiated at different deviator stress levels, and this curve was found to be different from the 1 day creep curve obtained from a previous study. A long-term stress relaxation test was also performed, and it showed linear reduction of deviator stress with the logarithm of time during stress relaxation. Observations made are all aligned with the phenomenon of static fatigue and the proposed mechanism for time effects in granular materials.
5
Zhang, Fu Jun, and Chuan Xiao Liu. "Experimental Study of Short-Term Creep Characteristics Base on Step Loading-Unloading Method for Hard Rock." Advanced Materials Research 774-776 (September 2013): 86–93. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.86.
Full textAbstract:
Based on experimental results of uniaxial compression and short-term creep using 8-step loading-unloading method, fine sandstone specimen, which lower creep limit is 27MPa, present typical brittle breakage properties of hard rock. The correlative coefficients of linear regression function for isochronous stress-strain curve are all higher than 0. 92, and the ratio of long-term strength to instantaneous strength reaches 94. 39%，which indicate that the whole creep of fine sandstone specimen is weak. The average correlative coefficients of linear regression function for isochronous stress- axial strain curve are 3. 92% higher than that of average correlative coefficients of linear regression function for isochronous stress- radial strain curve, so nonlinear creep property of the fine sandstone specimen in axial direction is correspondingly weaker than that in radial direction. Negative Gauss distribution can be applied collectively to nonlinear creep of fine sandstone specimen, which has obvious time effect.With increasing loading, the reduction degrees of average correlative coefficients of linear fitting functions of isochronous stress-axial strain curve and isochronous stress-radial strain curve are 0. 97% and 0. 67% respectively, which indicates the linear correlation decreases commonly. Thus, the degree of nonlinear creep for fine sandstone specimen increases along with loading stress with obvious stress effect.
6
Wellekens, J. B., Wim De Waele, Rudi Denys, Stijn Hertele, and Matthias Verstraete. "Interpretation of stress-strain curve in pipeline research." International Journal Sustainable Construction & Design 1, no. 1 (November 6, 2010): 40–45. http://dx.doi.org/10.21825/scad.v1i1.20393.
Full textAbstract:
For the design of on-shore pipelines installed in areas that are susceptible to ground movements and offshore pipelines, axial stresses above yield must be considered. In such so-called strain-based design,knowledge of the stress-strain behaviour of the pipeline steel and girth welds is highly important. These behaviours are influenced by many factors, including: welding parameters, operation temperature, tensile test specimen geometry and orientation, and microstructure of the steel. This paper focuses on the influence of the tensile test specimen geometry and orientation, for the case of UOE formed pipes. As regards the geometry, it is concluded that the stress-strain diagram is most representative for a flat fullthickness test specimen. As regards the orientation, the yield stress is higher for transversal test specimens, as compared to longitudinally oriented test specimens.
7
He, Xing, Junfeng Chen, Wei Tian, Yuebing Li, and Weiya Jin. "Low Cycle Fatigue Behavior of Steam Generator Tubes under Axial Loading." Materials 11, no. 10 (October 11, 2018): 1944. http://dx.doi.org/10.3390/ma11101944.
Full textAbstract:
Compared with the fatigue properties of the material (Inconel Alloy 690), the real fatigue lives of tubes are more meaningful in the fatigue design and assessment of steam generator (SG) tube bundles. However, it is almost impossible to get a satisfactory result by conducting fatigue tests on the tube directly. A tube with a uniform and thin wall easily fails near the clamping ends under cyclic loading due to the stress concentration. In this research, a set-up for fatigue tests of real tubes is proposed to overcome the stress concentration. With the set-up, low cycle fatigue tests were conducted in accordance with an existing fatigue design curve for Alloy 690. Strain control mode was applied with fully reversed push–pull loading under different strain amplitudes (0.15%, 0.2%, 0.3%, and 0.4%). A favourable result was obtained, and the low cycle fatigue behavior was investigated. The results showed that the fatigue life tested by the real tube was below the strain–life curve of Alloy 690 which was fitted by conventional solid specimens. A cyclic hardening behavior was found by the cyclic stress–strain curve when compared with the monotonic stress–strain curve.
8
Li, Gang, Zhen Yan, Jinli Zhang, Jia Liu, and Yu Xi. "Test Study on the Creep Behaviors of Tianjin Clays." E3S Web of Conferences 136 (2019): 07029. http://dx.doi.org/10.1051/e3sconf/201913607029.
Full textAbstract:
The drained triaxial creep tests were carriedout to investigate the relationshipsbetween axial strain and time, axial strain and deviatoricstress, and axial strain rate and time for the undisturbed samples of muddy clay and clay in Tianjin.Based on the creep test results, the Singh-Mitchell modelwas used for creep calculation. The results showed that the muddyclay and clay exhibited typical non-linear creep properties. The axial strain increasedwith time and then gradually tendedto be stable.The strain rate increasedasthe deviatoric stress increased, and the muddy clay and clay showedthe characteristics of attenuation creep under deviatoricstresses. The axial strain of muddy clay wassignificantly larger than that of clay, and reachedthestable state within 3000 minutes.Under low deviatoricstress, the slope of the isochronal curve was smaller; while under high deviatoric stress, the slope of the isochronal curve waslarger.The test results were in good agreement with the calculation results, which indicated that the Singh-Mitchell model wassuitable for describing the creep behaviorsof the undisturbed claysin Tianjin.
9
Wang, X. B. "Temperature-Dependent Shear Strain Localization of Aluminium-Lithium Alloy in Uniaxial Compression Using Zerilli-Armstrong and Gradient Plasticity Models." Materials Science Forum 519-521 (July 2006): 789–94. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.789.
Full textAbstract:
Gradient-dependent plasticity where a characteristic length is involved to consider the microstructural effect (interactions and interplaying among microstructures due to the heterogeneous texture) is introduced into Zerilli-Armstrong model based on the framework of thermally activated dislocation motion. Effect of initial temperature on the distributions of plastic shear strain and deformation in adiabatic shear band (ASB), the axial compressive stress-axial compressive strain curve, the shear stress-average plastic shear strain in ASB curve and the plastic shear strain corresponding to the occurrence of shear strain localization is investigated. The axial deformation within aluminum-lithium alloy specimen in uniaxial compression in strain-hardening stage is considered to be uniform. Beyond the peak compressive stress, a single ASB with a certain thickness determined by internal length is formed and intersects the specimen. The axial plastic deformation is decomposed into uniform deformation and localized deformation due to the shear slip along ASB. Lower temperature leads to earlier occurrence of shear strain localization, i.e., lower critical plastic compressive strain, steeper post-peak shear stress-average plastic shear strain in ASB curve, higher peak shear stress and more apparent shear strain localization. The calculated distributions of plastic shear strain and deformation in ASB are highly nonuniform due to the microstructural effect, as cannot be predicted by classical elastoplastic theory applicable to completely homogenous material. The predicted average plastic shear strains in ASB for different widths of ASB agree with the measured values for under-aged Al-Li alloy at 298K and at strain rate of approximately 103s-1.
10
Yang, Gang, Qing Yang, and Wen Hua Liu. "Study of Variation of Soil Stress State Based on the Curve of Normalized Strain- Pore Water Pressure." Applied Mechanics and Materials 275-277 (January 2013): 295–98. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.295.
Full textAbstract:
The cyclic behavior of normally consolidated silty clays was investigated by conducting a series of cyclic simple shear tests on one-dimensionally and isotropically consolidated reconstituted samples. The critical cyclic stress ratio was obtained by the normalized axial strain. Based on hysteretic curve of pore water pressure versus strain, dynamic characteristics of silty clay were investigated. The results showed that with increasing of cyclic loading, soil stress state can be divided into steady state, critical state and failure state based on the critical cyclic stress ratio. The hysteresis curve of pore water pressure versus strain was divided into two parts by cross point A. Compared with two parts, the variation law was obtained. When the upper part area was bigger than the lower part area, pore water pressure and axial strain continuously increase with cycle number; when the upper part area was smaller than the lower part area, pore water pressure and axial strain tended to be steady with cycle number.
11
Liu, Xiang, and Jiang Tao Kong. "Experimental Study of Stress-Strain Curves of Lightweight Aggregate Concrete." Advanced Materials Research 163-167 (December 2010): 1762–67. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1762.
Full textAbstract:
According to the contrast test of LC30, LC40 lightweight aggregate concrete and C30, C40 common concrete , the text researched the mechanical property of lightweight aggregate concrete and ordinary concrete in the same strength grade and obtained the regularity of stress-strain curve of lightweight aggregate concrete in different strength grade. Then we contrasted the experimental results and planning model, analysed the difference, and suggested that the standards should improve the descent stage of the stress-strain curve of lightweight aggregate concrete combined with correlative experiments data, and give the equation of the descent stage of stress-strain curves. Concrete material in axial compression is the basic physical mechanical performance of concrete material, and is the main basis for researching bearing capacity and deformation of concrete construction. The stress-strain relationship is all-around macroscopic reaction of basal compressive property . There have been many experiments work about the stress-strain relationship of lightweight aggregate concrete at home and abroad , and found the peak strain of lightweight aggregate concrete is higher than that of ordinary concrete in the context of same peak stress .In this paper, on the basis of experimental investigations of lightweight aggregate concrete , aim at the stress-strain relationship ,we have take comparison experiment about LC30,LC40 lightweight aggregate concrete and C30,C40 ordinary concrete , and sort out stress-strain curve under the condition of the shaft center being compressed, so get the average tress-strain curve of LC30,LC40 lightweight aggregate concrete , and analyse the curve.
12
Wang, Xiao Chu, Jun Wei Wang, and Hong Tao Liu. "Experimental Research on Stress-Strain Curve of Carbon Fiber Reinforced Concrete." Advanced Materials Research 668 (March 2013): 640–44. http://dx.doi.org/10.4028/www.scientific.net/amr.668.640.
Full textAbstract:
In order to further investigate the stress-strain curve of carbon fiber reinforced concrete, the curve of stress-strain is used segmentation tabulators on the basis of the existing tests. Based on the axial compression experiments of 9 carbon fiber concrete reinforced samples filled with different carbon fiber admixture amounts, the theoretical calculating formula of the stress-strain curve with different admixture amounts was proposed, and the theoretical formula of calculation parameters and carbon fiber volume fraction was putted forward. The experimental results show that the calculation parameters of the stress-strain curve increases with the increase of the carbon fiber admixture amounts. The theoretical calculating formula of the peak strain and carbon fiber volume fraction, the compressive strength, and the calculated results agreed well with the experimental results.
13
Kowalewski, Zbigniew L., and Tadeusz Szymczak. "An Influence of Step Cyclic Loading due to Torsion on Tensile Curve Variation." Key Engineering Materials 535-536 (January 2013): 181–84. http://dx.doi.org/10.4028/www.scientific.net/kem.535-536.181.
Full textAbstract:
The paper presents experimental results of tests carried out at room temperature on power engineering steel: 10H2M (11CrMo9-10) using thin-walled tubular specimens under biaxial stress state. The loading programme comprised different types of deformation, i.e. monotonic tension and cyclic torsion in the form of symmetric or asymmetric step-increasing strain amplitude. The main task of the paper was focused on investigation of an influence of the cyclic loading parameters on tensile curve variations. The magnitudes of axial strain and cyclic shear strain amplitude were small and did not exceed 1%. An analysis of the results showed a significant reduction of the axial stress (even equal 90% for the torsional amplitude ±0.8%, in both cases of cyclic loading). An influence of torsion frequency on the tensile stress curve was discovered within the range from 0.005Hz to 0.5Hz.
14
Frydrych, Iwona, Nannan Tao, Si Chen, Liping Wang, and Wei Wu. "Tensile-tensile Fatigue Behavior of Multi-axial Warp-knitted Reinforced Composite." Fibres and Textiles in Eastern Europe 26, no. 1(127) (February 28, 2018): 73–80. http://dx.doi.org/10.5604/01.3001.0010.7800.
Full textAbstract:
An experimental study was carried out on the fatigue behaviour of multi-axial warp-knitted fabric composites. Composite samples reinforced with multi-axial warp-knitted fabric/matrix were manufactured by the vacuum-assisted resin transfer moulding method. Tensile-tensile fatigue cycling was carried out at different load levels, and S-N curves, tensile stress-strain curve and stiffness degradation of the multi-axial composite samples were obtained. Finally post-fatigue tensile tests were done at a stress level of 75%, at the stages of 1/3N and 2/3N, and the equivalent residual strength and stiffness degradation were obtained.
15
Deng, Zong-cai, and Jiu-ling Qu. "The Experimental Studies on Behavior of Ultrahigh-Performance Concrete Confined by Hybrid Fiber-Reinforced Polymer Tubes." Advances in Materials Science and Engineering 2015 (2015): 1–18. http://dx.doi.org/10.1155/2015/201289.
Full textAbstract:
This paper conducts axial compression test of ultrahigh performance concrete- (UHPC-) filled hybrid FRP (HFRP) tubes, using the alternating hybrid technology to improve the deformation capacity of FRP tube and measure the axial compressive responses of ultimate strength, strains, and stress-strain curve of confined specimens. The test results show that the local rupture of HFRP tubes did not lead to explosive failure of UHPC cylinder, and its ductility is better than that of UHPC confined by only one type of FRP tube; HFRP tube can effectively improve the compressive strength and ultimate strain of UHPC specimens; the stress-strain curves divide into three distinct regions: linear phase, transition phase, and linear strengthening phase. None of the models provided a reasonable prediction for strength and strain of HFRP-confined UHPC specimen; therefore, a new ultimate strength and strain perdition model considering the confinement effectiveness of different hybrid FRP series was proposed. The new proposed model presented the best fitting results. The stress-strain responses predicted by the existing models are all below the experimental curves; therefore, a new three-stage constitutive model was proposed, which relatively fits the test curves better than the existing models.
16
Han, Tielin, Junping Shi, and Yunsheng Chen. "Mechanical Characteristics and Failure Characteristics of Jointed Rock under Axial Unloading and Radial Unloading." Advances in Civil Engineering 2020 (July 25, 2020): 1–15. http://dx.doi.org/10.1155/2020/8812621.
Full textAbstract:
In this research, we used precracked rock-like materials (simulating jointed rock masses) to assess the triaxial compression of cracked specimens under axial unloading and radial unloading paths. The research goal was to comparatively analyze and research the mechanical characteristics of cracked specimens to ascertain how deformation properties, strength properties, and failure features influence the overall mechanisms in context. The test results showed that the failure of specimens did not appear at peak stress under axial unloading and radial unloading. The elastic stage, yield stage, and failure stage of the stress-strain curves were not clearly defined in the testing process. However, the stress drop and the strain of resilience of the lateral strain-axial strain curve happened under this path because the lateral strain was significantly greater than the axial strain. This in turn led the volumetric strain to remain in a state of expansion throughout the testing process. The mechanical properties under this path are mainly influenced by the crack inclination angle, the unloading speed of radial pressure, and the initial confining pressure. However, there is a difference in the influence of these three factors on their mechanical parameters; that is, the influence of the crack inclination angle is the greatest, followed by that of the initial confining pressure, while that of the unloading speed of radial pressure is relatively small. Finally, the failure characteristics of specimens often present mixed tension-shear failure under axial unloading and radial unloading.
17
Zhang, Dongming, Yushun Yang, Hao Wang, Xin Bai, Chen Ye, and Shujian Li. "Experimental study on permeability characteristics of gas-containing raw coal under different stress conditions." Royal Society Open Science 5, no. 7 (July 2018): 180558. http://dx.doi.org/10.1098/rsos.180558.
Full textAbstract:
The present experimental study on permeability characteristics for raw coal under different stress states is implemented by applying the triaxial self-made ‘THM coupled with servo-controlled seepage apparatus for gas-containing coal’; the result indicates that the flow rate of gas in the coal sample gradually decreases with the nonlinear loading of axial pressure and increases with the nonlinear unloading of axial stress and confining pressure. The flow rate, axial stress and confining pressure curves all satisfy the negative exponential function relation. When the sample reaches the peak intensity, the sample will be destroyed and the stress will drop rapidly; then the flow rate of the sample will increase rapidly. At this stage, the flow rate and axial strain show an oblique ‘v' pattern. The flow rate of the coal sample increases nonlinearly with the increase of gas pressure; the relation curve between flow rate and gas pressure satisfies the power function relation. Under the same confining pressure and gas pressure conditions, the larger the axial stress, the smaller the flow rate of the coal sample. Under the same axial stress and gas pressure conditions, the flow rate of the coal sample will first decrease, but then increase as the confining pressure decreases. During the post-peak loading and unloading process, the flow rate of the coal sample will decrease with the loading of confining pressure but increase with the unloading of confining pressure, and there will be an increase in wave shape with the increase in axial strain. The flow rate of each loading and unloading confining pressure is higher than that of the previous loading and unloading confining pressure. At the post-peak stage, the relation curve between the flow rate of the coal sample and the confining pressure satisfies the power function relation in the process of loading and unloading confining pressure.
18
Lu, Ji Ping, Jian Hua Zuo, Shui Yuan Tang, and Yue Guang Wang. "Research of Radial-Axial Ring Rolling Process Curve." Advanced Materials Research 189-193 (February 2011): 589–94. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.589.
Full textAbstract:
During the rolling process of big size parts, crinkle and hollows often appear in the surfaces. The reason of producing the defects is that the motions of the rolling mill tool are not consistent with the deformation of the part. On the basis of the principle of radial-axial ring rolling, a dynamics model is put forward. The relationship between part deformation and motion parameters is set up. The stress and strain of the part are simulated in the Finite Element Method by DEFORM software. A ring rolling process curve is defined. The rolling process is controlled by the curve. It is able to make the deformation of the part be consistent with the process parameters, and improve the product quality.
19
Wang, X. B. "Failure Process and Stress-Strain Curve of Plane Strain Rock Specimen with Initially Random Material Imperfections." Key Engineering Materials 353-358 (September 2007): 1133–36. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1133.
Full textAbstract:
The failure process of heterogeneous rock specimen with initially random material imperfections in uniaxial plane strain compression and the macroscopically mechanical response are numerically modeled by using FLAC (Fast Lagrangian Analysis of Continua). A FISH function is generated to prescribe the initial imperfections within the heterogeneous specimen by using Matlab. The imperfection is weaker than the intact rock. Beyond the failure of the imperfection, it undergoes ideal plastic behavior, while intact rock exhibits linear strain-softening behavior and then ideal plastic behavior once failure occurs. The specimen with smooth ends is loaded at a constant strain rate and is divided into 3200 elements. The maximum numbers of the initial imperfections in five schemes are 100, 300, 500, 700 and 900. The effects of the number of the imperfections on the fracture process, the final fracture pattern and the complete stress-strain curve are investigated. Prior to the peak stress, some imperfections extend in the axial direction and then a part of them coalesce to form inclined shear bands. Beyond the peak stress, shear bands progressively intersect the specimen; in the process the number of the yielded elements approximately remains a constant. With an increase of the number of the initial imperfections, the spacing of shear fractures decreases, the peak stress and corresponding axial strain decrease; the post-peak branch of stress-strain curve becomes steeper; much more elements fail in tension; the number of the yielded elements in tension in the vicinity of the two lateral edges of the specimen remarkably increases.
20
Zhong, Sheng, Chuan Xiao Liu, Zhi Hao Liu, and Long Wang. "Creep Characteristics of Mudstone under Devastating or Integrated States by Uniaxial Tests." Applied Mechanics and Materials 204-208 (October 2012): 16–21. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.16.
Full textAbstract:
Based on general instantaneous strength test and uniaxial creep tests under devastating or integrated states, strain characteristics of mudstone in different stages have been determined. Analyzing strain features of mudstone developing in every stage of different tests, evolving creep law of mudstone under uniaxial devastating state may be validated, which axial limited creep strain under the decided loading standard is equal to that value at uniaxial complete strain-stress curve rearwards ultimate strength. Relationship between designed loading stress and its corresponding creep strain can be linear in uniaxial creep test of mudstone under integrated state, while must not be a determinate secant of uniaxial complete strain-stress curve. Studying results present that terminal creep strain of rock with certain loading levels and under devastating state can be only corresponded with an exclusive point of traditional uniaxial complete strain-stress curve rearwards the ultimate strength, and the extended limited creep courses of mudstone will answer for Boltzmann function.
21
Wang, Junbao, Qiang Zhang, Zhanping Song, and Yuwei Zhang. "Creep properties and damage constitutive model of salt rock under uniaxial compression." International Journal of Damage Mechanics 29, no. 6 (December 4, 2019): 902–22. http://dx.doi.org/10.1177/1056789519891768.
Full textAbstract:
To study the creep property of salt rock, uniaxial compression creep tests on salt rock specimens were carried out. The test results indicate that there is no steady creep of the salt rock used in this test in a strict sense. Even in the steady creep stage, the creep rate of salt rock changes continuously over time, but with a relatively smaller change range. When the axial stress does not exceed 9.5 MPa, the isochronous stress–strain curve of salt rock is approximately straight. While the axial stress exceeds 9.5 MPa, the isochronous stress–strain curve deflects to the strain axis, and the larger the axial stress, the more obvious the deflection. Thus, the long-term strength of the salt rock used in this test can be determined as 9.5 MPa. A mathematical expression for predicting the creep failure time of rock is proposed on the basis of assuming the change rule of rock strength over time conforms to the Usher function. Then starting from the variation in deformation modulus with respect to time in the creep process of salt rock, the elastic modulus of the damaged rock material is characterized by the deformation modulus, and the creep damage evolution equation of rock is established. Combined with the continuous damage mechanics theory, a new creep damage constitutive model for rock is proposed. The rationality of the model is verified using the uniaxial compression creep test results of salt rock. The results show that the new model can not only describe the attenuation and the steady creep of salt rock under low stress level, but also reflect the whole creep failure process under high stress level. The predicted curves under different axial stresses are all in good agreement with the test data.
22
Ke, Bo, Jian Zhang, Hongwei Deng, and Xiangru Yang. "Dynamic Characteristics of Sandstone under Coupled Static-Dynamic Loads after Freeze-Thaw Cycles." Applied Sciences 10, no. 10 (May 12, 2020): 3351. http://dx.doi.org/10.3390/app10103351.
Full textAbstract:
The effect of temperature fluctuation on rocks needs to be considered in many civil engineering applications. Up to date the dynamic characteristics of rock under freeze-thaw cycles are still not quite clearly understood. In this study, the dynamic mechanical properties of sandstone under pre-compression stress and freeze-thaw cycles were investigated. At the same number of freeze-thaw cycles, with increasing axial pre-compression stress, the dynamic Young’s modulus and peak stress first increase and then decrease, whereas the dynamic peak strain first decreases and then increases. At the same pre-compression stress, with increasing number of freeze-thaw cycles, the peak stress decreases while the peak strain increases, and the peak strain and peak stress show an inverse correlation before or after the pre-compression stress reaches the densification load of the static stress–strain curve. The peak stress and strain both increase under the static load near the yielding stage threshold of the static stress–strain curve. The failure mode is mainly shear failure, and with increasing axial pre-compression stress, the degree of shear failure increases, the energy absorption rate of the specimen increases first and then decreases. With increasing number of freeze-thaw cycles, the number of fragments increases and the size diminishes, and the energy absorption rates of the sandstone increase.
23
Jia, Jinglong, Fenghai Yu, Yunliang Tan, and Xuepeng Gao. "Experimental Investigations on Rheological Properties of Mudstone in Kilometer-Deep Mine." Advances in Civil Engineering 2021 (January 23, 2021): 1–12. http://dx.doi.org/10.1155/2021/6615379.
Full textAbstract:
The soft rock roadway in deep high-stress environment has the problems of strong rheology and large deformation. Based on the analysis of the stress distribution of the surrounding rock of the roadway in a kilometer-deep mine, rheological tests under different stress paths are carried out for mudstone in a kilometer-deep mine. The rheological deformation curve, damage characteristics, and change rule of the main mechanical parameters of mudstone under different stress conditions are studied. The results show the following: (1) the peak strength of the triaxial compression of mudstone is closely related to confining pressure, and, with increasing confining pressure, the confining pressure effect decreases gradually; (2) the strain increases slowly under uniaxial loading, and, with increasing axial pressure, the velocity of rheological deformation increases nonlinearly, and the amount of mudstone deformation increases with time; (3) under the condition of unloading confining pressure with constant axial pressure, with decreasing confining pressure, the instantaneous axial and radial strains of mudstone specimen increase nonlinearly, the rheological strain and velocity of mudstone increase gradually, and the lateral rheological strain is close to the axial rheological strain; and, (4) in the unloading confining pressure with axial compression triaxial test, with increasing deviating stress, the axial and radial instantaneous strain increments of mudstone decrease gradually, the lateral strain and rheological velocity of mudstone increase gradually, and the lateral strain is approximately 2.05 times the axial strain. These conclusions reveal the rheological characteristics of the mudstone under different surrounding rock conditions and provide a theoretical basis for the excavation deformation and support control of roadways.
24
Risitano, Antonino, Carmelo Clienti, and Giacomo Risitano. "Determination of Fatigue Limit by Mono-Axial Tensile Specimens Using Thermal Analysis." Key Engineering Materials 452-453 (November 2010): 361–64. http://dx.doi.org/10.4028/www.scientific.net/kem.452-453.361.
Full textAbstract:
In this work is indicated how it could be possible to evaluate the limit stress of the thermo-elastic phase of deformation by thermo-analysing the surface of the specimen during a static traction test. Adding the temperature curve measured on a small area of the surface (the hottest) to the classic stress-strain curve, it is possible to evaluate a limit temperature T0 coincident with the beginning of the non linear trend of the curve. The corresponding stress value is coincident with the fatigue limit of the analyzed component. As an example, the results of traction tests performed on two notched specimens, where the change of linearity in the temperature curve during static traction test was evident, are reported.
25
Rey Calderón, Alfredo Alán, and Alberto Díaz Díaz. "New Aspects in the Mechanical Behavior of a Polycarbonate Found by an Experimental Study." Advances in Materials Science and Engineering 2018 (November 11, 2018): 1–14. http://dx.doi.org/10.1155/2018/1540919.
Full textAbstract:
The aim of this paper was to analyze in detail the mechanical behavior of a polycarbonate by means of uniaxial tensile and compressive tests and to reveal new key aspects that must be taken into account in any predictive model. Uniaxial monotonic and creep-recovery tests were carried out at a variety of temperatures, stress levels, and load rates to get a complete description of the material response. Prior to mechanical testing, the material was subjected to a thermal rejuvenation in order to eliminate any previous aging and to obtain reliable and useful results. In every test, a complete determination of the strain state was assured by measuring axial and transverse strains with strain gauges. During the tests, significant asymmetry effects and viscous phenomena already reported by other authors were confirmed. The newest finding is that a nonlinear master transverse strain/axial strain curve matches perfectly with the experimental curves. This master curve is temperature- and rate-independent. Another originality of this paper is the disclosure of an instantaneous, hypoelastic-like behavior at high strain rates. The experimental observations presented in this study should be incorporated by a theoretical model whose aim is to accurately predict the mechanical behavior of polycarbonate subjected to any 3D stress state.
26
FaghihKhorasani, Fatemeh, Mohammad Zaman Kabir, Mehdi AhmadiNajafabad, and Khosrow Ghavami. "Predicting compressive stress‒strain curves of structural adobe cubes based on Acoustic Emission (AE) hits and Weibull distribution." International Journal of Structural Integrity 10, no. 6 (December 2, 2019): 766–91. http://dx.doi.org/10.1108/ijsi-11-2018-0082.
Full textAbstract:
Purpose The purpose of this paper is to provide a method to predict the situation of a loaded element in the compressive stress curve to prevent failure of crucial elements in load-bearing masonry walls and to propose a material model to simulate a compressive element successfully in Abaqus software to study the structural safety by using non-linear finite element analysis. Design/methodology/approach A Weibull distribution function was rewritten to relate between failure probability function and axial strain during uniaxial compressive loading. Weibull distribution parameters (shape and scale parameters) were defined by detected acoustic emission (AE) events with a linear regression. It was shown that the shape parameter of Weibull distribution was able to illustrate the effects of the added fibers on increasing or decreasing the specimens’ brittleness. Since both Weibull function and compressive stress are functions of compressive strain, a relation between compressive stress and normalized cumulative AE hits was calculated when the compressive strain was available. By suggested procedures, it was possible to monitor pretested plain or random distributed short fibers reinforced adobe elements (with AE sensor and strain detector) in a masonry building under uniaxial compression loading to predict the situation of element in the compressive stress‒strain curve, hence predicting the time to element collapse by an AE sensor and a strain detector. In the predicted compressive stress‒strain curve, the peak stress and its corresponding strain, the stress and strain point with maximum elastic modulus and the maximum elastic modulus were predicted successfully. With a proposed material model, it was illustrated that the needed parameters for simulating a specimen in Abaqus software with concrete damage plasticity were peak stress and its corresponding strain, the stress and strain point with maximum elastic modulus and the maximum elastic modulus. Findings The AE cumulative hits versus strain plots corresponding to the stress‒strain curves can be divided into four stages: inactivity period, discontinuous growth period, continuous growth period and constant period, which can predict the densifying, linear, non-linear and residual stress part of the stress‒strain relationship. By supposing that the relation between cumulative AE hits and compressive strain complies with a Weibull distribution function, a linear analysis was conducted to calibrate the parameters of Weibull distribution by AE cumulative hits for predicting the failure probability as a function of compressive strain. Parameters of m and θ were able to predict the brittleness of the plain and tire fibers reinforced adobe elements successfully. The calibrated failure probability function showed sufficient representation of the cumulative AE hit curve. A mathematical model for the stress–strain relationship prediction of the specimens after detecting the first AE hit was developed by the relationship between compressive stress versus the Weibull failure probability function, which was validated against the experimental data and gave good predictions for both plain and short fibers reinforced adobe specimens. Then, the authors were able to monitor and predict the situation of an element in the compressive stress‒strain curve, hence predicting the time to its collapse for pretested plain or random distributed short fibers reinforced adobe (with AE sensor and strain detector) in a masonry building under uniaxial compression loading by an AE sensor and a strain detector. The proposed model was successfully able to predict the main mechanical properties of different adobe specimens which are necessary for material modeling with concrete damage plasticity in Abaqus. These properties include peak compressive strength and its corresponding axial strain, the compressive strength and its corresponding axial strain at the point with maximum compressive Young’s modulus and the maximum compressive Young’s modulus. Research limitations/implications The authors were not able to decide about the effects of the specimens’ shape, as only cubic specimens were chosen; by testing different shape and different size specimens, the authors would be able to generalize the results. Practical implications The paper includes implications for monitoring techniques and predicting the time to the collapse of pretested elements (with AE sensor and strain detector) in a masonry structure. Originality/value This paper proposes a new method to monitor and predict the situation of a loaded element in the compressive stress‒strain curve, hence predicting the time to its collapse for pretested plain or random distributed short fibers reinforced adobe (with AE sensor and strain detector) in a masonry building under uniaxial compression load by an AE sensor and a strain detector.
27
Wang, Huailiang, Min Wei, Yuhui Wu, Jianling Huang, Huihua Chen, and Baoquan Cheng. "Mechanical Behavior of Steel Fiber-Reinforced Lightweight Concrete Exposed to High Temperatures." Applied Sciences 11, no. 1 (December 24, 2020): 116. http://dx.doi.org/10.3390/app11010116.
Full textAbstract:
The mechanical characteristics of steel fiber-reinforced lightweight concrete (SFLWC) under high temperatures are studied in this paper. Different concrete matrices, including all-lightweight concrete (ALWC) and semi-lightweight concrete (SLWC), and different steel fibers with hooked ends and crimped shapes are considered as objects. In addition, normal-weight limestone aggregates concrete (NWC), no-fiber ALWC, and SLWC were tested after high-temperature treatment as a control group. The temperature effects on the splitting tensile strength, ultrasonic pulse velocity, compressive stress–strain curve, elastic module, peak strain, and axial compressive strength of the SFLWC were investigated. The results showed that, with increasing exposure temperature, both the axial compressive strength and the elastic modulus decreased, while the axial peak strain has a certain increase, and hence the stress–strain curves were gradually flattened. The toughness of all the concretes increased first and then reduced with increasing temperature, while the specific toughness of all the concretes increased with the increase in temperature. Compared with NWC and SLWC, ALWC had a better capacity to resist high temperatures, especially temperatures > 400 °C. Adding steel fibers can improve the capacity of energy absorption, specific toughness, and residual splitting tensile strength of lightweight concrete (LWC) before and after it is exposed to high temperatures. Based on a regression analysis, a segmented constitutive equation for LWC and SFLWC under uniaxial compression was derived from fitting the experimental findings, and the fitting curve agrees well with the test results.
28
Andersen, Glen R., Christopher W. Swan, Charles C. Ladd, and John T. Germaine. "Small-strain behavior of frozen sand in triaxial compression." Canadian Geotechnical Journal 32, no. 3 (June 1, 1995): 428–51. http://dx.doi.org/10.1139/t95-047.
Full textAbstract:
The stress–strain behavior of frozen Manchester fine sand has been measured in a high-pressure low-temperature triaxial compression testing system developed for this purpose. This system incorporates DC servomotor technology, lubricated end platens, and on-specimen axial strain devices. A parametric study has investigated the effects of changes in strain rate, confining pressure, sand density, and temperature on behavior for very small strains (0.001%) to very large (> 20%) axial strains. This paper presents constitutive behavior for strain levels up to 1%. On-specimen axial strain measurements enabled the identification of a distinct upper yield stress (knee on the stress–strain curve) and a study of the behavior in this region with a degree of precision not previously reported in the literature. The Young's modulus is independent of strain rate and temperature, increases slightly with sand density in a manner consistent with Counto's model for composite materials, and decreases slightly with confining pressure. In contrast, the upper yield stress is independent of sand density, slightly dependent on confining pressure (considered a second order effect), but is strongly dependent on strain rate and temperature in a fashion similar to that for polycrystalline ice. Key words : frozen sand, high-pressure triaxial compression, strain rate, temperature, modulus, yield stress.
29
Vincent, Thomas, and Togay Ozbakkloglu. "Influence of FRP-to-Concrete Gap Effect on Axial Strains of FRP-Confined Concrete Columns." Advanced Materials Research 1119 (July 2015): 760–65. http://dx.doi.org/10.4028/www.scientific.net/amr.1119.760.
Full textAbstract:
This paper reports on an experimental investigation on the influence of FRP-to-concrete interface gap, caused by concrete shrinkage, on axial compressive behavior of concrete-filled FRP tube (CFFT) columns. A total of 12 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were manufactured. 3 of these specimens were instrumented to monitor long term shrinkage strain development and the remaining 9 were tested under monotonic axial compression. The influence of concrete shrinkage was examined by applying a gap of up to 0.06 mm thickness at the FRP-to-concrete interface, simulating 800 microstrain of shrinkage in the radial direction. Axial strain recordings were compared on specimens instrumented with two different measurement methods: full-and mid-height linear variable displacement transformers (LVDTs). Results of the experimental study indicate that the influence of interface gap on stress-strain behavior is significant, with an increase in interface gap resulting in a decrease and increase in the compressive strength and ultimate axial strain, respectively. It was also observed that an increase in interface gap leads to a slight loss in axial stress at the transition region of the stress-strain curve. Finally, it is found that an increase in the interface gap results in a significant decrease in the ratio of the ultimate axial strains obtained from mid-section and full-height LVDTs.
30
Leong, Martin, Lars CT Overgaard, Isaac M. Daniel, Erik Lund, and Ole T. Thomsen. "Interlaminar/interfiber failure of unidirectional glass fiber reinforced composites used for wind turbine blades." Journal of Composite Materials 47, no. 3 (March 22, 2012): 353–68. http://dx.doi.org/10.1177/0021998312440132.
Full textAbstract:
A unidirectional glass fiber/epoxy composite was characterized under multi-axial loading by testing off-axis specimens under uniaxial tension and compression at various angles relative to the fiber direction. Iosipescu shear tests were performed with both symmetric and asymmetric specimens. Tests were performed on both 1-2 and 1-3 material coordinate planes. Strain gauges and Digital Image Correlation were used to record the stress–strain responses. A new approach was used to define a ‘failure initiation strength’ by analyzing the recorded stress–strain curves. The experimentally determined failure stresses were compared with the predictions of the maximum stress, Tsai-Wu and Northwestern University failure criteria. It was found that using the approach of analyzing the stress–strain curve to define a point of material failure initiation, it was possible to obtain good correlation between the experimental data and predictions by both the Tsai-Wu and the NU failure criteria.
31
Müller, Wolfgang H., Holger Worrack, and Jens Sterthaus. "Experimental Setup for the Determination of Mechanical Solder Materials Properties at Elevated Temperatures." Materials Science Forum 638-642 (January 2010): 3793–98. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.3793.
Full textAbstract:
The fabrication of microelectronic and micromechanical devices leads to the use of only very small amounts of matter, which can behave quite differently than the corresponding bulk. Clearly, the materials will age and it is important to gather information on the (changing) material characteristics. In particular, Young’s modulus, yield stress, and hardness are of great interest. Moreover, a complete stress-strain curve is desirable for a detailed material characterization and simulation of a component, e.g., by Finite Elements (FE). However, since the amount of matter is so small and it is the intention to describe its behavior as realistic as possible, miniature tests are used for measuring the mechanical properties. In this paper two miniature tests are presented for this purpose, a mini-uniaxial-tension-test and a nanoindenter experiment. In the tensile test the axial load is prescribed and the corresponding extension of the specimen length is recorded, both of which determines the stress-strain- curve directly. The stress-strain curves are analyzed by assuming a non-linear relationship between stress and strain of the Ramberg-Osgood type and by fitting the corresponding parameters to the experimental data (obtained for various microelectronic solders) by means of a non-linear optimization routine. For a detailed analysis of very local mechanical properties nanoindentation is used, resulting primarily in load vs. indentation-depth data. According to the procedure of Oliver and Pharr this data can be used to obtain hardness and Young’s modulus but not a complete stress-strain curve, at least not directly. In order to obtain such a stress-strain-curve, the nanoindentation experiment is combined with FE and the coefficients involved in the corresponding constitutive equations for stress and strain are obtained by means of the inverse method. The stress-strain curves from nanoindentation and tensile tests are compared for two mate-rials (aluminum and steel). Differences are explained in terms of the locality of the measurement. Finally, material properties at elevated temperature are of particular interest in order to characterize the materials even more completely. We describe the setup for hot stage nanoindentation tests in context with first results for selected materials.
32
Cheng, Yanhui, and Weijun Yang. "Influence of Microscopic Parameters on the Stress-Strain Relation in Rocks." Advances in Civil Engineering 2018 (June 25, 2018): 1–7. http://dx.doi.org/10.1155/2018/7050468.
Full textAbstract:
Macromaterial properties should correspond to the mesoscopic parameters simulated in practical engineering problems. Discrete element contains a variety of particle models and its corresponding mesoscopic parameters, and the one-to-one relationship between the mesoscopic parameters and macroscopic parameters is difficult to establish. This paper studies the influence of microscopical characteristic parameters, such as particle contact stiffness ratio, parallel bond stiffness ratio, particle contact modulus, and parallel bond elastic modulus, on the stress-strain relation in rocks, which shows that (1) The range of particle contact stiffness ratio kn/ks largely varies, but the stress-strain relation curve is relatively small. The particle contact stiffness has less influence on the elastic modulus of the simulated specimens than kn/ks. (2) Before the failure of the specimen, the axial strain corresponding to the peak compressive strength increases with the increase in the stiffness ratio kn¯/ks¯ of the parallel bond. (3) The particle contact modulus Ec has a great influence on the elastic modulus of sandstone and is characterized by the increase in the particle contact modulus Ec, corresponding axial strain for the peak compressive strength decreases, and the slope of the stress-strain relationship curves before damage increases. (4) The elastic modulus of the parallel bond greatly influences the uniaxial compressive strength, and the relationship between them is proportional.
33
Wang, Zhong Xian, Xiang Li, and Rui Feng Zhang. "Reliability Assessment on Pipeline with Axial Surface Crack." Applied Mechanics and Materials 166-169 (May 2012): 1879–82. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.1879.
Full textAbstract:
Stress constraints have a significant impact on the stress-strain fields of the crack front. In this paper, the weight function method is used to calculate the stress intensity factor K and constraint parameter T-stress at the crack front of pressure pipeline with a axial semi-elliptical surface crack. Based on the R6 procedure and considering the influence of stress constraint on fracture toughness, a modified failure assessment curve(FAC) and a computational formula are proposed to predict the fracture probability. In the end, a typical numerical example is presented to illustrate the proposed methodology and analyze the influences of crack geometry and axial stress on the failure probability of pipeline,where the crack size, material property parameter and load follow certain probability distribution.
34
Banerjee, J. K. "Barreling of Solid Cylinders Under Axial Compression." Journal of Engineering Materials and Technology 107, no. 2 (April 1, 1985): 138–44. http://dx.doi.org/10.1115/1.3225789.
Full textAbstract:
Axisymmetric compression tests of solid aluminum cylinders, over a wide range of “aspect ratios” (length/diameter) and both under dry as well as lubricated conditions, suggest that the resulting curvature of the “barrel” formed fits closely a circular arc and its radius follows a power law with the true axial compressive stress. The true compressive stress-strain curve, extrapolated from the experimental data in each test, shows that within the variety of lubricants used the Specific Forming Energy is minimum with teflon sheets as dry lubricant, and increases successively with silicon spray, motor oil, and dry friction.
35
Munir, Muhammad Junaid, Syed Minhaj Saleem Kazmi, Yu-Fei Wu, Xiaoshan Lin, and Muhammad Riaz Ahmad. "Axial Stress-Strain Performance of Recycled Aggregate Concrete Reinforced with Macro-Polypropylene Fibres." Sustainability 13, no. 10 (May 20, 2021): 5741. http://dx.doi.org/10.3390/su13105741.
Full textAbstract:
The addition of macro-polypropylene fibres improves the stress-strain performance of natural aggregate concrete (NAC). However, limited studies focus on the stress-strain performance of macro-polypropylene fibre-reinforced recycled aggregate concrete (RAC). Considering the variability of coarse recycled aggregates (CRA), more studies are needed to investigate the stress-strain performance of macro-polypropylene fibre-reinforced RAC. In this study, a new type of 48 mm long BarChip macro-polypropylene fibre with a continuously embossed surface texture is used to produce BarChip fibre-reinforced NAC (BFNAC) and RAC (BFRAC). The stress-strain performance of BFNAC and BFRAC is studied for varying dosages of BarChip fibres. Results show that the increase in energy dissipation capacity (i.e., area under the curve), peak stress, and peak strain of samples is observed with an increase in fibre dosage, indicating the positive effect of fibre addition on the stress-strain performance of concrete. The strength enhancement due to the addition of fibres is higher for BFRAC samples than BFNAC samples. The reduction in peak stress, ultimate strain, toughness and specific toughness of concrete samples due to the utilisation of CRA also reduces with the addition of fibres. Hence, the negative effect of CRA on the properties of concrete samples can be minimised by adding BarChip macro-polypropylene fibres. The applicability of the stress-strain model previously developed for macro-synthetic and steel fibre-reinforced NAC and RAC to BFNAC and BFRAC is also examined.
36
Ju, Yan Zhong, De Hong Wang, and Fei Jiang. "Experimental Investigation on Stress-Strain Curves of Reactive Powder Concrete under Uniaxial Compression." Advanced Materials Research 261-263 (May 2011): 192–96. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.192.
Full textAbstract:
Based on experiments of uniaxial compression and flexural experiments, the basic mechanical properties (compressive strength and flexural strength) of reactive powder concrete (RPC) were investigated, the effect of the steel fiber content on mechanical properties of RPC was studied in this work. The resu1ts indicate that the axial compressive strength of RPC had no obvious change with the change of steel fiber content. When the steel fiber content varied from 1.0% to 2.0%, the flexural strength of RPC had no obvious change.When the steel fiber content varied from 2.0% to 5.0%, the flexural strength of RPC increased dramaticlly with the increase of steel fibers content. According to experiment curves, an equation for the compressive stress-strain curve of RPC was deduced with different stee1 fiber content.
37
Wang, X. B. "Joint Inclination Effect on Strength, Stress-Strain Curve and Strain Localization of Rock in Plane Strain Compression." Materials Science Forum 495-497 (September 2005): 69–76. http://dx.doi.org/10.4028/www.scientific.net/msf.495-497.69.
Full textAbstract:
Peak strength, mechanical behavior, and shear band (SB) of anisotropic jointed rock (JR) were modeled by Fast Lagrangian Analysis of Continua (FLAC). The failure criterion of rock was a composite Mohr-Coulomb criterion with tension cut-off and the post-peak constitutive relation was linear strain-softening. An inclined joint was treated as square elements of ideal plastic material beyond the peak strength. A FISH function was written to find automatically elements in the joint. For the lower or higher joint inclination (JI), the higher peak strength and more apparent strain-softening behavior are observed; the failure of JR is due to the slip along the joint and the new generated SBs initiated at joint’s two ends. For the lower JI, the slope of softening branch of stress-strain curve is not concerned with JI since the new and longer SBs’s inclination is not dependent on JI, as can be qualitatively explained by previous analytical solution of post-peak slope of stress-strain curve for rock specimen subjected to shear failure in uniaxial compression based on gradient-dependent plasticity. For the higher JI, the post-peak stress-strain curve becomes steeper as JI increases since the contribution of the new SBs undergoing strain-softening behavior to axial strain of JR increases with JI. For the moderate JI, the lower strength and ideal plastic behavior beyond the elastic stage are found, reflecting that the inclined joint governs the deformation of JR. The present numerical prediction on anisotropic peak strength in plane strain compression qualitatively agrees with triaxial experimental tests of many kinds of rocks. Comparison of the present numerical prediction on JI corresponding to the minimum peak strength of JR and the oversimplified theoretical result by Jaeger shows that Jaeger’s formula has overestimated the value of JI.
38
Ma, Wei Ha. "The Study on BFRP Binding Force of Secondary Compression Tests of Concrete Short Columns." Advanced Materials Research 418-420 (December 2011): 116–20. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.116.
Full textAbstract:
This article has test researched on the BFRP constraint compression of the concrete short columns secondary stress axial compression , got C20, C25 reinforced concrete specimens of stress-strain curve test, studies show that strengthened specimens of strength and deformation of the increased significantly, and the degree of improve related with the size of initial stress. Through testing the processing and analysis of data, concludes that the calculation formula of peak stress and strain of the strengthening specimens under the secondary stress and can reflect the influence of different condition of initial stress .
39
Ding, Guosheng, Jianfeng Liu, Lu Wang, Zhide Wu, and Zhiwei Zhou. "Discussion on Determination Method of Long-Term Strength of Rock Salt." Energies 13, no. 10 (May 13, 2020): 2460. http://dx.doi.org/10.3390/en13102460.
Full textAbstract:
Due to the extremely low permeability and the excellent creep behavior, rock salt is the optimal surrounding rock of underground energy storage. The long-term safe operation of the rock salt energy storage is closely related to the creep behavior and long-term strength of rock salt, but few researches focus on the long-term strength of rock salt. In order to more accurately predict the long-term strength of rock salt, the isochronous stress–strain curve method and the volume expansion method for determining the long-term strength were analyzed and discussed based on axial compression tests and axial creep tests. The results show that the isochronous stress–strain curve method is intuitive but will greatly increase the test cost and test time to obtain a satisfactory result. The volume expansion method is simple, but the long-term strength obtained according to the inflection point of volumetric strain is much greater than the actual long-term strength of rock salt. Therefore, a new method applicable to rock salt was proposed based on the evolution of damage in rock salt in this paper, which takes the corresponding stress value at the damage initiation point as the long-term strength. The long-term strength determined by this method is consistent with that by the isochronous stress–strain curve method. The method is more economical and convenient and aims to provide a reference for the long-term stability study of underground salt caverns.
40
Zhu, Guo Liang. "Experimental Research on the Stress - Strain Curve of Regional Confined Concrete under Single Axial Press." Applied Mechanics and Materials 584-586 (July 2014): 1289–92. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1289.
Full textAbstract:
Regional confined concrete is base on confined concrete. It is the theory and application of a new attempt and development on confined concrete. To apply it to the actual project, we need to research mechanical properties and establish constitutive relationship of regional confined concrete. According to the research, we had carried on a series of tests, founded the stress-strain constitutive model of regional confined concrete under single axial press. The accuracy of theoretical analysis were more fully verified , and a theoretical basis for the application was provided.
41
Yang, Yugui, Feng Gao, and Yuanming Lai. "Compressive Mechanical Properties and Micromechanical Characteristics of Warm and Ice-Rich Frozen Silt." Advances in Materials Science and Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/379560.
Full textAbstract:
It is recognized experimentally that the compressibility of warm and ice-rich frozen soil is remarkable under loading, which will cause a significant deformation and affect the stability of infrastructure constructed in cold region. In this paper, the real-time computerized tomography tests of warm and ice-rich frozen silt were carried out. The microstructure characteristics in the process of loading were studied, and the macromechanical behaviors were obtained at the same time. The test results showed that the stress-strain curve of warm and ice-rich frozen silt is sensitive to temperature; the peak stress was greatly enhanced with the decrease of temperature, and the section area increases with the increase of axial strain; the water content mainly decreases with the increase of axial strain at −1°C; the change of water content is not obvious at −2°C in the loading process. The density damage changes little at first and then increases with the further increase of axial strain.
42
Sun, Yidan, Yu Yang, and Min Li. "Dynamic Behavior and Fatigue Damage Evolution of Sandstone under Uniaxial Cyclic Loading." Shock and Vibration 2020 (April 16, 2020): 1–9. http://dx.doi.org/10.1155/2020/1452159.
Full textAbstract:
The mechanical response characteristics of sandstone specimens under different stress amplitudes and loading frequencies were tested by a TAW-2000 rock triaxial testing machine. The characteristics of the stress-strain curve and the evolution process of strain damage under cyclic loading are analyzed. Based on creep theory and the disturbance state concept, a theoretical model between the axial compressive strain, axial compressive stress, and cycle number is established. The results show that there exists an upper threshold value of stress in cyclic loading above which the specimen will be damaged. As peak stress increases, the energy loss and irreversible deformation caused by damage gradually increase. When loading to an unstable peak stress under cyclic loading, the fatigue damage of sandstone under cyclic loading undergoes three characteristic stages: the initial stage; the stable stage; and the accelerated failure stage. The parameters of the strain damage model based on the disturbance state concept of sandstone are identified by test data, and the rationality of the model is validated by comparing theoretical values with experimental measurements.
43
Li, Qiang, Di Tao Niu, and Lei Liu. "The Experimental Study on Reinforced Concrete Short-Columns Restrained by Corroded Stirrups." Advanced Materials Research 446-449 (January 2012): 1376–79. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1376.
Full textAbstract:
The impact of stirrup corrosion on the constraint of corroded reinforced concrete(CRC) column is an pressing problem that needs to be solved. In this paper, 12 corroded CRC short-columns and 3 uncorroded CRC short-columns with dimension of 150mm×150mm×450mm have been prepared for the axial compression experiment. Through the experiment, the total cross-section stress-strain curves of the short-columns were measured under different degrees of stirrups corrosion, and the effects of corrosion rate of stirrups on the shape of the total cross-section stress-strain curves, bearing capacity, deformation and the mechanical parameters of confined concrete have been investigated. According to the results, the corrosion of stirrups has reduced their section, changed the material quality and damaged the concrete cover, which reduces the constraint to the core concrete; the shape changes of stress-strain curve illustrate that the destructive form of short-columns developed form ductility damage to brittle failure gradually.
44
Tsai, Pei Hsun, Yu Hsiang Liang, and Pei Chun Lin. "Numerical Modeling on the Stress-Strain Behavior of Sand via Disturbed State Concept Model." Key Engineering Materials 748 (August 2017): 328–32. http://dx.doi.org/10.4028/www.scientific.net/kem.748.328.
Full textAbstract:
The disturbed state concept (DSC), proposed by Desai, is a powerful constitutive modeling for the simulation of the material behaviors of strain hardening or softening of soil. These material parameters can be decided by the results of the triaxial compression test of soil. Some triaxial drained test were performed to obtain the deviator stress vs. axial strain behaviors of Ottawa sand with relative densities Dr ＝20% and 90% under three different confining pressures. The result shows that the experimental data and the results of the DSC model showed good correspondence. In study for disturbance parameters to effect on the curve of axial strain vs. deviator stress, it can be found that the deviator stress after peak markedly decreases when the values of disturbance parameters are reduced. The effect of disturbance parameter A on the trend for deviator stress decrease after peak is higher than that of parameter B.
45
Gao, Chong, and Takeshi Iwamoto. "Finite Element Analysis on a Newly-Modified Method for the Taylor Impact Test to Measure the Stress-Strain Curve by the Only Single Test Using Pure Aluminum." Metals 8, no. 8 (August 15, 2018): 642. http://dx.doi.org/10.3390/met8080642.
Full textAbstract:
In this study, finite element analyses are performed to obtain a stress-strain curve for ductile materials by a combination between the distributions of axial stress and strain at a certain time as a result of one single Taylor impact test. In the modified Taylor impact test proposed here, a measurement of the external impact force by the Hopkinson pressure bar placed instead of the rigid wall, and an assumption of bi-linear distribution of an axial internal force, are introduced as well as a measurement of deformed profiles at certain time. In order to obtain the realistic results by computations, at first, the parameters in a nonlinear rate sensitive hardening law are identified from the quasi-static and impact tests of pure aluminum at various strain rates and temperature conducted. In the impact test, a miniaturized testing apparatus based on the split Hopkinson pressure bar (SHPB) technique is introduced to achieve a similar level of strain rate as 104 s−1, to the Taylor test. Then, a finite element simulation of the modified test is performed using a commercial software by using the user-subroutine for the hardening law with the identified parameters. By comparing the stress-strain curves obtained by the proposed method and direct calculation of the hardening law, the validity is discussed. Finally, the feasibility of the proposed method is studied.
46
Zhao, Junliang, Chenhao Xu, Linzhu Sun, and Dongyan Wu. "Behaviour of FRP-confined compound concrete–filled circular thin steel tubes under axial compression." Advances in Structural Engineering 23, no. 9 (January 20, 2020): 1772–84. http://dx.doi.org/10.1177/1369433219900941.
Full textAbstract:
This article presents test results of a recent study on the axial compressive behaviour of fibre-reinforced polymer–confined compound concrete–filled thin steel tubes. The usage of compound concrete, which is a mixture of fresh concrete and large pieces of recycled concrete lumps, can recycle waste concrete in a simple but effective way. Totally, three series of tests were conducted, with the parameters including the relative strength between fresh concrete and recycled concrete lumps, the volumetric percentage (i.e. mix ratio) of recycled concrete lumps, the diameter-to-thickness ratio of the steel tubes, and the thickness of the fibre-reinforced polymer jackets being investigated. The stress–strain curves of the steel tube and compound concrete core were derived and the effects of different parameters were then examined and discussed. An existing stress–strain curve model of fibre-reinforced polymer–confined normal concrete-filled steel tubes was also found performing well in predicting the behaviour of fibre-reinforced polymer–confined compound concrete-filled steel tubes.
47
You, Xiang, Rui Dong Wang, Shi Ming Cui, Yong Jie Liu, and Qing Yuan Wang. "Low Cycle Fatigue Behavior of Q345b Steel under Uniaxial Cycle Loading." Advanced Materials Research 904 (March 2014): 95–98. http://dx.doi.org/10.4028/www.scientific.net/amr.904.95.
Full textAbstract:
In this paper, the low cycle fatigue (LCF) behavior of Q345b steel was experimentally investigated in fully reversed cyclic axial configurations at room temperature. The strain range of 0.3%, 0.4%, 0.5%, 0.6% and 0.7% at constant strain rate of 0.005 s-1 was adopted. Cyclic stress-strain curve and strain life relationship were analyzed according to the Ramberg-Osgood relationship and Coffin-Manson relationship respectively. Suitable parameters were obtained showing good agreements with the experimental fatigue data.
48
Gao, Jin He, Yan Bin Huang, and Shou Long Zhang. "Mechanic Model of Push-Out Test of Over-Thick CFST." Applied Mechanics and Materials 513-517 (February 2014): 314–18. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.314.
Full textAbstract:
Analyze mechanical behavior of over-thick concrete filled steel tube ( over-thick CFST ) subjected to axial compression and revealed adhesive slip law of steel tube/concrete. Axial symmetry elasticity modeling of the concrete column which is constrained by over-thick steel tube and pushed out under axial compressive load is set up. The push-out test was carried out and axial displacements of concrete column and steel tube were measured. On the base of the test,the adhesive layer between the concrete and the steel tube is introduced and shearing stress-shearing strain curve is set up. The results show that the adhesive stress between steel tube and concrete is uniform along the height,and uniform slipping along the height exists.Therefore the adhesive stress between steel tube and concrete can be precisely measured by push-out test of over-Thick CFST subjected to axial compression. The following conclusions can be drown that axial symmetry elasticity modeling is correct for simulating push-out test of over-thick CFST. There is an adhesive thin player between steel tube and concrete, the slip can be equivalent to shearing deformation of the adhesive layer. The relation of shearing stress-shearing strain can be determined by the push-out test.
49
Bert, C. W., and F. Gordaninejad. "Forced Vibration of Timoshenko Beams Made of Multimodular Materials." Journal of Vibration and Acoustics 107, no. 1 (January 1, 1985): 98–105. http://dx.doi.org/10.1115/1.3274723.
Full textAbstract:
This paper presents a transfer-matrix analysis for determining the sinusoidal vibration response of thick, rectangular cross-section beams made of “multimodular materials” (i.e., materials which have different elastic behavior in tension and compression, with nonlinear stress-strain curves approximated as piecewise linear). An experimentally determined stress-strain curve for aramid-cord rubber is approximated by four straight-line segments (two segments in tension and two segments in compression). To validate the transfer-matrix results, a closed-form solution is also presented for the special case in which the neutral-surface location is uniform along the length of the beam. Also, comparisons are made among multimodular, bimodular (two line segments), and unimodular models. Numerical results for axial displacement, transverse deflection, bending slope, bending moment, transverse shear and axial forces, and the location of the neutral surface are presented for the multimodular model. Effects of translatory and rotatory inertia coefficients on axial force are investigated for a clamped-clamped beam. Moreover, natural frequencies associated with the first three modes of a clamped-free beam are presented. Transfer-matrix results agree very well with the closed-form results for the corresponding material model (one, two, or four segments).
50
Cheng, Tao, Keqin Yan, Huazhi Zhang, Xianfeng Luo, and Shengfang Li. "Uniform Nonlinear Constitutive Model and Parameters for Clay in Different Consolidation Conditions Based on Regression Method." Mathematical Problems in Engineering 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/804586.
Full textAbstract:
The nonlinear constitutive relations of clay are investigated considering different initial conditions. Highly compressible clay is selected as the test sample. Two groups of tri-axial compression tests are performed, respectively, afterK0consolidation and isotropic consolidation. On the basis of the framework ofE~vmodel, a uniform nonlinear constitutive model is proposed by fitting the test data. With the average slope of the unloading-reloading curve selected as the unloading modulus, the unloading function is constructed as the loading-unloading criterion. Moreover, a comparison between the experimental stress-strain curves and the results predicted by the constitutive model is made. It is shown that the prediction is reasonable, which can reflect the stress-strain behavior of the soil under theK0consolidation and isotropic consolidation conditions. The maximum relative error of the two series of curves is not remarkable, less than 6%.