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Journal articles on the topic 'Compressive modulus'
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1
Saud, Abdullah F., Hakim S. Abdelgader, and Ali S. El-Baden. "Compressive and Tensile Strength of Two-Stage Concrete." Advanced Materials Research 893 (February 2014): 585–92. http://dx.doi.org/10.4028/www.scientific.net/amr.893.585.
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An experimental investigation was conducted to evaluate the compressive, tensile strength and modulus of elasticity of two-stage concrete (TSC) at different water-to-cement ratios. The primary objectives were to measure the elastic modulus, compressive strength and splitting tensile strength of TSC and to determine if there is a quantifiable relationship between compressive and tensile strength. Behavior of TSC in compression has been well documented, but there are little published data on its behavior in tension and modulus of elasticity. This paper presents the experimental results of preplaced, crushed granite aggregate concreted with five different mortar mixture proportions. A total of 48 concrete cylinders were tested in unconfined compression modulus of elasticity and splitting tension at 28 and 90 days. It was found that the modulus of elasticity and splitting tensile strength of two-stage concrete is equivalent or higher than that of conventional concrete at the same compressive strength. Splitting tensile strength can be conservatively estimated using the ACI equation for conventional concrete.
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Lu, Jie Qun, Yuan Tian, Jia Geng Chen, Chen Yu Zhu, Fu Yuan Zeng, Jin Cheng Yang, and Wei Wang. "Experimental Study on CFRP-PVC Confined RAC under Axial Compression." Solid State Phenomena 294 (July 2019): 143–49. http://dx.doi.org/10.4028/www.scientific.net/ssp.294.143.
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Compared with natural aggregate concrete (NAC), the cylinder compressive strength and elastic modulus of Recycled aggregate concrete (RAC) are decreased, but the brittleness is increased. The axial compression performance of RAC can be improved by external confinement. In this paper, the effects of Polyvinyl chloride (PVC) pipe confinement and composite confinement of PVC pipe and Carbon Fiber Reinforced Polymer (CFRP) on the axial compression performance of RAC were investigated. The results showed that with the increase of the replacement rate of recycled coarse aggregate, the cylinder compressive strength, peak strain and elastic modulus of RAC were decreased; PVC pipe confinement could significantly improve the cylinder compressive strength, peak strain and elastic modulus of RAC; the CFRP could further improve the cylinder compressive strength and elastic modulus of PVC-RAC to a certain extent, and could significantly enhance the peak strain of PVC-RAC. PVC pipe and CFRP-PVC pipe confinement could improve the axial compression performance of RAC more effectively than NAC. Consequently, PVC pipe and CFRP-PVC pipe confinement could reduce the influence of recycled aggregate (RA) quality on variability of RAC axial compression performance.
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Mantilla, J. N. R., Diego N. Miranda, Jamile Salim Fuina, and E. V. M. Carrasco. "Mechanical Characteristics of Pavers with Iron Ore Tailings." Applied Mechanics and Materials 864 (April 2017): 330–35. http://dx.doi.org/10.4028/www.scientific.net/amm.864.330.
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The objective of this study is to evaluate experimentally the mechanical compressive strength and static modulus of elasticity of concrete pavers for floors made with iron ore tailings as aggregate concrete. Pavers were manufactured with four different concrete mixtures (cement, natural sand, industrial sand, iron ore tailings, crushed stone), and performed simple compression tests to determine the compressive strength and modulus of elasticity. The pavers manufactured with those concrete mixtures showed greater strength specified by the Brazilian standard. It was possible to find a correlation between modulus of elasticity and compressive strength.
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Wang, Ping, Hao Xu, Rong Chen, Jingmang Xu, and Xiaohui Zeng. "Experimental Research on Compression Properties of Cement Asphalt Mortar due to Drying and Wetting Cycle." Advances in Materials Science and Engineering 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/769248.
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Uniaxial compression test of cement asphalt (CA) mortar specimens, due to drying and wetting cycle of 0, 2, 4 and 8 times, is carried out by using the electronic universal test machine, with the strain rate ranging from 1 × 10−5 s−1to 1 × 10−2 s−1. The effects of strain rate and drying and wetting cycle time on the compressive strength, elasticity modulus, and stress-strain full curve are investigated. Experimental results show that the strain-stress full curve of CA mortar is affected obviously by strain rate and drying and wetting cycle time. The compressive strength and elasticity modulus increase with the strain rate under the same drying and wetting cycle time. The compressive strength and elasticity modulus decrease with the increase of drying and wetting cycle time in the same strain rate. The lower the strain rate is, the greater the compressive strength and elasticity modulus of CA mortar decrease. When the strain rate is 1 × 10−5 s−1and drying and wetting cycle time is 8, the largest reduction of average compressive strength of CA mortar is 40.48%, and the largest reduction of elasticity modulus of CA mortar is 35.51%, and the influence of drying and wetting cycle on the compressive strength of CA mortar is greater than its influence on the elasticity modulus.
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Fartini, M. S., M. S. Abdul Majid, Mohd Afendi, R. Daud, and Azizul Mohamad. "Effect of Nano-Clay and their Dispersion Techniques on Compressive Properties of Unsaturated Polyester Resin." Applied Mechanics and Materials 554 (June 2014): 27–31. http://dx.doi.org/10.4028/www.scientific.net/amm.554.27.
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This paper aims to understand the relationship between processing parameters and compressive properties of nanoclay filled polyester resin (dispersion method and wt% of nanoclay particles). Unsaturated polyester resin with 0-5 wt% nanoclay content was prepared by hand mixing and through shears mixing of water bath shaker. Static uniaxial compression tests were conducted to investigate how the unsaturated polyester resins with nanoclay contents and processing will effect on the compressive stress-strain behaviour and compression properties. The experimental results show that the compressive strength and elastic modulus of nanomodified resin are significantly affected by type of mixing methods to prepare the specimens and the ratio of nanoparticles content during mixing. It was found out that the compressive strength and compressive modulus increase with the nanoclay content. The findings also indicate the dispersion of nanoclay by hand-mixed method yield higher compressive strength compared to that dispersed by water shaker bath.
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SELYAEV, V. P., L. I. KUPRIYASHKINA, E. L. KECHUTKINA, N. N. KISELEV, and O. V. LIYASKIN. "Mechanical Characteristics of Vacuum Thermal Insulation Panels: Deformation Diagrams, Strength, Deformation Modules." Stroitel'nye Materialy 785, no. 10 (2020): 44–51. http://dx.doi.org/10.31659/0585-430x-2020-785-10-44-51.
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The results of studying the mechanical properties of vacuum insulation panels are presented. The compressive strength and deformation modules (elastic and secant) under compression and shear are determined. The dependence of the mechanical characteristics of vacuum insulation panels (VIP) on the type and quantitative ratio of fillers is shown. It is established that the diagram of deformation of the VIP under compression can be described by an analytical function. Experimental studies of the properties of VIP have established that the deformation diagram of VIP has the form characteristic for materials that self-strengthen during loading with a compressive load and is adequately described by the function of G. V. Bulfinger. A method is proposed for determining the coefficients α and β that makes it possible to verify the approximating function using experimental data. Polynomial models describing the dependence of the elastic modulus, strength, and thermal conductivity coefficient on the composition and quantitative ratio of fiber and powder fillers are developed. It is established that the numerical values of the strain modulus depend on the type, amount of powder filler, and their ratio to the fibrous filler. The values of strain and strength models increase with increasing content and size of filler particles. A method for determining the shear modulus for VIP has been developed. It has been experimentally established that the value of the shear modulus for VIP depends on both the filler composition and the characteristics of the panel film shell. Keywords: vacuum insulation panel, diatomite, silica fume, thermal conductivity, strength, compression, shear, modulus of deformation.
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Xu, Minjun, Xiaochuan Chen, Jun Wang, and Yong Li. "Finite element analysis modeling research on the compression process of cotton fiber assembly." Textile Research Journal 90, no. 11-12 (November 7, 2019): 1414–27. http://dx.doi.org/10.1177/0040517519886558.
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In order to analyze the compressive stress state of a cotton fiber assembly in the compression process, a new cotton fiber assembly model, the tetrakaidecahedral porous cotton fiber assembly model, is presented based on the idea of three-dimensional open-cell foam material modeling. Based on the model, the compression process of cotton fiber assembly is analyzed using the finite element method. The change in the compressive stress of the cotton fiber assembly in the compression process is successfully described. The measurement method of compressive modulus of the cotton fiber assembly is also studied, and the relation between compressive modulus and relative density of the cotton fiber assembly is determined. Finally, the effect of different moisture regain on compressive stress of the cotton fiber assembly is analyzed, and the reference value of moisture regain in the cotton baling process is given. The results show that the simulation results are consistent with the actual situation. Therefore, the established model of cotton fiber assembly has validity.
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Wang, Chen, and Wentao Li. "Factors Affecting the Mechanical Properties of Cement-Mixed Gravel." Advances in Materials Science and Engineering 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/8760325.
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A study has been conducted to investigate the mechanical properties of cement-mixed gravel using the unconfined compression test and the tensile test. Basic factors including the curing period, the water-binder ratio, the cement content, and the strain rate were evaluated. Ordinary Portland cement with fly ash was employed as the cementation agent for preparing cemented samples. The results indicate that the unconfined compressive strength, the deformation modulus, and the tensile strength increase with the increase in the curing period. The ratio of tensile strength to unconfined compressive strength has no distinct change after 7 days. An optimum water-binder ratio can be obtained. The unconfined compressive strength and deformation modulus decrease as the water-binder ratio decreases and increase from the optimum water-binder ratio. With the increasing of the cement content, the unconfined compressive strength increases distinctly, the deformation modulus increases significantly when the cement content is less than 4% and then increased slowly, and the failure strain increases to a peak value and then decreases. With the increasing of the strain rate, the unconfined compressive strength increases slightly and the deformation modulus increases slowly. The failure strain decreases with an increase in the strain rate.
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Hou, Yun Fen, and Dong Min Wang. "The Effect of Activators on the Fly Ash-Based Geopolymers." Key Engineering Materials 477 (April 2011): 85–90. http://dx.doi.org/10.4028/www.scientific.net/kem.477.85.
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This paper studies the influences of concentration and modulus of sodium silicate solution (Na activator) and sodium potassium silicate solution (Na-K activator) on the phase composition, microstructure and strength development in the geopolymers prepared using Class F fly ash. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and MAS NMR were utilized. It shows that the compressive strength increases while Na activator solution modulus increases, but when modulus exceeds 1.4, the compressive strength decreases, and it decreases markedly while modulus is greater than 2.0. The compressive strength improves with increase of sodium silicate solution concentration, and when concentration is 32%, compressive strength reaches the maximum, and then it reduces with concentration increment. It shows that the compressive strength increases while Na-K activator solution modulus increases, but when modulus exceeds 1.7, the compressive strength decreases, and it decreases markedly while modulus is greater than 2.0. The compressive strength improves with increase of Na-K activator solution concentration, and when concentration is 36%, compressive strength reaches the maximum. The main product of reaction in the geopolymeric material is amorphous alkali aluminosilicate gel.
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Wang, Min, C. L. Au, P. K. Lai, and William Bonfield. "Tensile and Compressive Behaviours and Properties of a Bone Analogue Biomaterial." Key Engineering Materials 284-286 (April 2005): 693–96. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.693.
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For the purpose of mimicking the structure and matching mechanical properties of human cortical bone, a natural composite material, hydroxyapatite (HA) reinforced high density polyethylene (HDPE) has been developed as a bioactive, analogue material for bone replacement. This synthetic composite material is now in clinical use. To understand the deformation behaviour and determine mechanical properties of HA/HDPE composite under different loading modes and loading conditions, tensile and compression tests were performed in the current investigation. It was observed that under tension, HA/HDPE composite exhibited two types of deformation behaviour: ductile and brittle. Under compression, the composite deformed in a ductile manner and did not fracture at high compressive strains. It was found that an increase in HA content resulted in increases in Young’s modulus, compressive modulus, tensile strength and compressive yield strength of the composite. A higher strain rate led to higher modulus and strength values and lower tensile fracture strains of the composite.
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Zhi, Chao, and Hai Ru Long. "Investigation on Compression Properties of Syntactic Foam Reinforced by Warp Knitted Spacer Fabric." Advanced Materials Research 1095 (March 2015): 531–34. http://dx.doi.org/10.4028/www.scientific.net/amr.1095.531.
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The study aimed to investigate the compression behaviors of syntactic foam reinforced by warp knitted spacer fabric (SF-WKSF). Two kinds of SF-WKSF samples were prepared with warp knitted spacer fabric (WKSF) of different surface layer structures. The compression tests were carried out by MTS 810 material test system and the compression properties of SF-WKSF were analyzed based on its compressive stress–strain curves and modulus values obtained from test results. It is indicated that the surface layer structure of WKSF has significant effects on the compression performance of SF-WKSF, the SF-WKSF made with denser surface layer structure shows higher compressive modulus and yield strength compared to neat syntactic foam (NSF).
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Lim, Seungwook, and Dan G. Zollinger. "Estimation of the Compressive Strength and Modulus of Elasticity of Cement-Treated Aggregate Base Materials." Transportation Research Record: Journal of the Transportation Research Board 1837, no. 1 (January 2003): 30–38. http://dx.doi.org/10.3141/1837-04.
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Experimental study on the development of strength and modulus of elasticity of cement-treated aggregate base (CTAB) materials was undertaken. Unconfined uniaxial compression tests were conducted with 189 samples for 16 CTAB mixtures at different ages. Two different aggregates, conventional crushed limestone base and recycled concrete materials, were used in the test program. Using the test results, equations were proposed to estimate the development of compressive strength and modulus of elasticity of CTAB materials with time. Test results indicated that the relationship between the compressive strength and elastic modulus of CTAB materials could be expressed in a single equation regardless of aggregate type and mixture proportions.
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Hashim, Ali Mudhafar, and Mohammed Mansour Kadhum. "Compressive Strength and Elastic Modulus of Slurry Infiltrated Fiber Concrete (SIFCON) at High Temperature." Civil Engineering Journal 6, no. 2 (February 1, 2020): 265–75. http://dx.doi.org/10.28991/cej-2020-03091469.
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SIFCON is a special type of fiber reinforced concrete (FRC) with an unattached fiber matrix that gives the composite matrix important tensile properties and, due to its high fiber content, SIFCON also has distinctive and unique ductility and energy absorption properties. Higher temperature resistance is one of the most important parameters affecting the durability and service life of the material. In this research, the compression strength and elastic modulus of Slurry Infiltrated Fiber Concrete (SIFCON) were tested both before and after exposure to high temperatures. Two fire exposure durations of 2 and 3 hours are examined. In addition to room temperatures, three temperature ranges of 400 ° C, 600 ° C and 900 ° C have been introduced. The results of the experiment showed that the compressive strength and elastic modulus decreased after exposure to high temperatures. The drastically reduction of compressive strength took place with increasing temperature above 600 °C. While, the reduction in elastic modulus values is more significant than the decrease in compressive strength at the same fire flame temperatures. The residual compressive strength and elastic modulus at 900 °C were in the range of (52.1% to 59.6%) and (30.6% to 34.1%) respectively.
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Voiconi, Tudor, Emanoil Linul, Liviu Marsavina, Jaroslav Kováčik, and Marcin Kneć. "Experimental Determination of Mechanical Properties of Aluminium Foams Using Digital Image Correlation." Key Engineering Materials 601 (March 2014): 254–57. http://dx.doi.org/10.4028/www.scientific.net/kem.601.254.
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This paper presents an experimental characterization of three different types of closed-cell aluminium alloy foams (AlMg1Si0.6, AlSi12Mg0.6 and AlMg0.6Si0.3) under static compressive loading. This study was carried out on half-cylindrical specimens with skin. The influence of foam density on compressive behaviour was investigated for densities ranging from 430 kg/m3 to 935 kg/m3. The compression tests were performed at room temperature (23°C) with a constant crosshead speed of 0.5 mm/min. Strain distribution, yield stress and compressive modulus values were recorded using Digital Image Correlation. Experimental results show that the mechanical properties (Youngs Modulus, yield stress and plateau stress) increase with density.
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Dang, Xu Dan, Meng Wei, Xin Li Wang, and Jun Xiao. "Finite Element Analysis of X-Cor Sandwich’s Compressive Modulus." Advanced Materials Research 228-229 (April 2011): 259–64. http://dx.doi.org/10.4028/www.scientific.net/amr.228-229.259.
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By contrasting the two finite models, a practical finite element computational model of X-cor sandwich’s compressive modulus was proposed. Through numerical analysis the X-cor sandwich’s stress field and compressive modulus were achieved and the effects of changing Z-pin’s radius, density, angle and volume fraction to the X-cor sandwich’s compressive modulus were analyzed. The numerical analysis results indicate that as the Z-pin’s angle increases the X-cor sandwich’s compressive modulus decreases, as the Z-pin’s radius, density and volume fraction increase the X-cor sandwich’s compressive modulus increases. Through the computation of finite model the influencing trends of X-cor sandwich’s parameters are achieved and the rationality of the proposed finite model is verified.
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Fartini, M. S., M. S. Abdul Majid, Mohd Afendi, N. A. M. Amin, and Azizul Mohamad. "Effects of Elevated Temperatures on the Compression Strength of Nanoclay Filled Unsaturated Polyester Resin." Applied Mechanics and Materials 554 (June 2014): 208–12. http://dx.doi.org/10.4028/www.scientific.net/amm.554.208.
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The paper describes the effects of the montmorillonite (MMT) fillers commonly known as nanoclay, on the compression properties of unsaturated polyester resins at different weight percentage of nanoclay. Modified resin specimens with 1, 3 and 5 wt. % of nanoclay contents were prepared and subjected to compressive tests according to ASTM D695. The static uniaxial compression testing were conducted at various temperatures ranging from room temperature (RT) to the temperature closer to its glass transition temperature Tg to study the effect of nanoclay fillers on the compressive stress-strain behaviour at high temperatures (room temperature, 35, 45, and 75°C). The mechanical properties of the nanomodified resin including the elastic modulus, maximum stress and failure strain were determined. The experimental results imply that adding these nanoclay fillers has enhanced the elastic modulus, compressive strength, and toughness without sacrificing the strain to failure and thermal stability of the unsaturated polyester. However it was found that generally, all specimens showed degradation in compressive strength with increases in temperatures.
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Ruan, Fangtao, Zhenzhen Xu, Dayin Hou, Yang Li, and Changliu Chu. "Enhancing Longitudinal Compressive Properties of Unidirectional FRP Based on Microbuckling Compression Failure Mechanism." Journal of Engineered Fibers and Fabrics 13, no. 1 (March 2018): 155892501801300. http://dx.doi.org/10.1177/155892501801300110.
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In this study, a new methodology to improve the longitudinal compressive strength and modulus of ultra-high molecular weight polyethylene (UHMWPE) fiber-reinforced epoxy resin matrix is developed. The proposed method involves wrapping a UHMWPE fiber bundle with a poly-p-phenylene benzobisoxazole fiber filament using a winding method, and using these bundles to fabricate unidirectional UHMWPE fabric. UHMWPE/epoxy composites were fabricated using vacuum-assisted resin-transfer molding (VARTM), and the compression properties of the composite were evaluated and compared to investigate the effect of the filament wrapping. Improvements in the compressive modulus were achieved for filaments wound with applied tension, and when increasing the filament-winding spacing; however, the compressive strength decreased with an increase in the filament-winding spacing. Results obtained confirm that fiber microbuckling failure occurred in the composite under longitudinal compression, and that inhibiting the buckling length of the fiber improved compressive properties. These results may be useful when designing the mechanical properties of fiber-reinforced polymer composites.
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Gao, Danying, Tao Zhang, Yihong Wang, Yiming Kong, Dawei Li, and Yang Meng. "Analysis and Prediction of Compressive Properties for Steel Fiber-and-Nanosilica-Reinforced Crumb Rubber Concrete." Advances in Civil Engineering 2020 (March 5, 2020): 1–15. http://dx.doi.org/10.1155/2020/9693405.
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The disposal of waste tire rubber has gained more attention from the viewpoint of green, environmental protection, and sustainability. Numerous attempts have been stated on the properties of crumb rubber concrete (CRC) and observed that there is a large reduction of compressive strength and elastic modulus of CRC with the increase of the rubber substitution rate. Based on the CRC with the crumb rubber volume content of 5%, the steel fibers and nanosilica were added to CRC to make steel fiber-and-nanosilica-reinforced crumb rubber concrete (SFNS-CRC) in this paper. The effects of the steel fiber volume content and nanosilica content on the compressive properties of SFNS-CRC were studied, including compressive strength, elastic modulus, peak strain, compression toughness, and failure pattern. The test results indicated that the modulus of elasticity and compressive strength of SFNS-CRC have the increasing tendency with the addition of steel fibers and nanosilica. Moreover, the peak strains have a significant increase with the increase of the steel fiber content and nanosilica replacement ratio. The compressive stress-strain curves of SFNS-CRC gradually plump with the increase of the steel fibers and nanosilica. Finally, the prediction formulas for the compressive strength, elastic modulus, and peak strain of SFNS-CRC were set up. A simple predicted model of the stress-strain curve for SFNS-CRC was proposed, which considers the effect of steel fibers and nanosilica.
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Zhang, Yi, Ephraim Suhir, and Yuan Xu. "Effective Young's modulus of carbon nanofiber array." Journal of Materials Research 21, no. 11 (November 2006): 2948–54. http://dx.doi.org/10.1557/jmr.2006.0363.
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We developed a methodology for the evaluation of the effective Young's modulus (EYM) of the vertically aligned carbon nanofibers array (CNFA). The carbon nanofibers array is treated in this study as a continuous structural element, and, for this reason, the determined EYM might be appreciably different (actually, lower) than the Young's modulus (YM) of the material of an individual carbon nanotube or a nanofiber. The developed methodology is based on the application of a compressive load onto the carbon nanofibers array, so that each individual carbon nanofiber experiences axial compression and is expected to buckle under the compressive load. The relationship between the applied compressive stress and the induced displacement of the carbon nanofiber array is measured using a table version of an Instron tester. It has been found that the carbon nanofiber array exhibits nonlinear behavior and the EYM increases with an increase in the compressive load. The largest measured EYM of the carbon nanofiber array turned out to be about 90 GPa. It has been found also that the fragmentary pieces of lateral graphitic layer in the carbon nanofiber array resulted in substantial worsening of the quality of the carbon nanofibers. This might be one of the possible reasons why the measured EYM turned out to be much lower than the theoretical predictions reported in the literature. The measured EYM is also much lower than the reported in the literature atomic force microscopy (AFM)-based data for the EYM for multiwalled carbon nanotubes (MWCNTs) that possess uniform and straight graphitic wall structure. Our transmission electron microscope (TEM) observations have revealed indeed poor structural qualities of the plasma-enhanced chemical vapor deposition (PECVD) grown CNFs.
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Yang, Shuai, and Wenbai Liu. "The Effect of Changing Fly Ash Content on the Modulus of Compression of Stabilized Soil." Materials 12, no. 18 (September 10, 2019): 2925. http://dx.doi.org/10.3390/ma12182925.
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Adding a curing agent can enhance the mechanical properties of soil including its compressive strength. However, few studies have quantitatively analyzed the compressive strength and microstructure of soils to explore the impact of changes in the microstructure on compressive strength. In addition, the cost of curing agents is too high to be widely used. In this study, curing agents with different proportions of fly ash were added to dredger fill to reduce the amount of curing agents needed. The quantitative analysis of the relationships between the modulus of compression Es and microstructures of stabilized soil samples is presented. The modulus of compression Es was gauged from compression tests. Microscopic images acquired using a scanning electron microscope were processed using the Image-Pro Plus (IPP) image processing software. The microscopic parameters, obtained using IPP, included the average equivalent particle size Dp, the average equivalent aperture size Db, and the plane pore ratio e. This research demonstrated that the fly ash added to the curing agent achieved the same effect as the curing agent, and the amount of curing agent required was reduced. Therefore, the modulus of compression for stabilized soil can be improved. This is due to the hydration products (i.e., calcium silicate hydrate, calcium hydroxide, and ettringite), produced by the hydration reaction, and which adhere to the surface of the particles and fill the spaces among them. Thus, the change in the pore structure and the compactness of the particles helps to increase the modulus of compression. In addition, there was a good linear relationship between the modulus of compression and the microscopic parameters. Using the mathematical relationships between the macroscopic and microscopic parameters, correlations can be built for macro–microscopic research.
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Sun, Ji Shu, Li Jie Ma, Yuan Ming Dou, and Ji Zhou. "Effect of Strain Rate on the Compressive Mechanical Properties of Concrete." Advanced Materials Research 450-451 (January 2012): 244–47. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.244.
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Concrete is one of the most widely used construction material throughout the world. But the properties of concrete under different strain rates differ from each other greatly. In order to investigate the effect of strain rate on concrete compressive mechanical properties, compressive experiments of concrete specimens (C35) are carried out on MTS, with the uniaxial strain rates ranging from 10-5/s to 10-2/s. The compressive mechanical properties of concrete under different stain rates, which include compressive strength, elastic modulus, peak strain and Poisson's ratio are studied systematically. The formulas which can describe the change laws of the compressive properties of concrete under different the strain rates are proposed. The test results show that the compresseive strength and elastic modulus of concrete would increase with the strain rate increasing. The effect of strain rate on peak strain and and Poisson's ratio is not significant. These research achievements can contribute to grasp the dynamic properties and build the dynamic constitutive models of concrete.
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Nica, Irina, Gianina Iovan, Simona Stoleriu, Cristina Angela Ghiorghe, Galina Pancu, Radu Comaneci, and Sorin Andrian. "Comparative Study Regarding the Compressive Strength of Different Composite Resins Used for Direct Restorations." Materiale Plastice 55, no. 3 (September 30, 2018): 447–53. http://dx.doi.org/10.37358/mp.18.3.5049.
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The aim of this study was to evaluate and to compare the compression behavior under identical mechanical tests, of three different composite resins, by determining Young�s modulus for compression, ultimate compressive strength and ultimate compressive strain. The studied materials were: Filtek Z250 Universal Restorative, Filtek Z550 and Filtek Bulk Fill Posterior Restorative (3M ESPE, St. Paul, MN, USA). Fifteen cylindrical samples, having 6 mm in height and 5 mm in diameter, were made from each material, using plastic molds. The samples were subjected to quantitative analysis of the compression behavior after mechanical tests. The fractured fragments of the samples were subjected to qualitative surface evaluation by scanning electron microscopy. Results were statistically analyzed using one-way analysis of variance (ANOVA) with Tukey�s post hoc test. Filtek Z250 had the lowest value of Young�s modulus for compression and the results were statistically significant (p[0.05) when compared to Filtek Bulk Fill Posterior Restorative and Filtek Z550. There were no statistically significant differences between all three materials regarding ultimate compressive strength (p]0.05). The lowest value for ultimate compressive strain was recorded for Filtek Bulk Fill.
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deBotton, G., and K. Schulgasser. "Bifurcation of Orthotropic Solids." Journal of Applied Mechanics 63, no. 2 (June 1, 1996): 317–20. http://dx.doi.org/10.1115/1.2788866.
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We consider a large deformation plane-strain problem involving a compressible orthotropic solid subjected to uniaxial compressive loading along one of the principle directions which is aligned with the boundary of a half-space. An exact solution for the displacement field is obtained and a condition for the smallest compressive load corresponding to the onset of a surface instability is determined. It is shown that when the compression occurs along the stiffest direction this condition is expressible in terms of a cubic polynomial, and that the corresponding critical load is lower than the well-known estimate which determines the critical load to be equal to the inplane shear modulus.
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Kocáb, Dalibor, Libor Topolář, Barbara Kucharczyková, Petr Pőssl, and Michaela Hoduláková. "Observation of the Development of the Elastic Modulus and Strength in a Polymer-Cement Mortar Using the Acoustic Emission Method." Solid State Phenomena 272 (February 2018): 76–81. http://dx.doi.org/10.4028/www.scientific.net/ssp.272.76.
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The paper describes an experiment focused on observing the development of the elastic modulus and compressive strength in a polymer-cement mortar during the first 28 days of aging. The specimens (aged 3 and 28 days) were tested for the static and dynamic modulus of elasticity using two methods – the ultrasonic pulse velocity test and the resonance method. During the test of the modulus of elasticity in compression the mortar’s behaviour was also examined by means of the acoustic emission method, which is based on the recording of mechanical pulses caused by dilation waves generated by microcracks that form during loading. The outcome of the experiment is an evaluation of the polymer-cement mortar’s behaviour in terms of the development of its elastic modulus and compressive strength as well as in terms of the material’s acoustic response during loading.
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Park, Seonghun, and Gerard A. Ateshian. "Dynamic Response of Immature Bovine Articular Cartilage in Tension and Compression, and Nonlinear Viscoelastic Modeling of the Tensile Response." Journal of Biomechanical Engineering 128, no. 4 (January 4, 2006): 623–30. http://dx.doi.org/10.1115/1.2206201.
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Very limited information is currently available on the constitutive modeling of the tensile response of articular cartilage and its dynamic modulus at various loading frequencies. The objectives of this study were to (1) formulate and experimentally validate a constitutive model for the intrinsic viscoelasticity of cartilage in tension, (2) confirm the hypothesis that energy dissipation in tension is less than in compression at various loading frequencies, and (3) test the hypothesis that the dynamic modulus of cartilage in unconfined compression is dependent upon the dynamic tensile modulus. Experiment 1: Immature bovine articular cartilage samples were tested in tensile stress relaxation and cyclical loading. A proposed reduced relaxation function was fitted to the stress-relaxation response and the resulting material coefficients were used to predict the response to cyclical loading. Adjoining tissue samples were tested in unconfined compression stress relaxation and cyclical loading. Experiment 2: Tensile stress relaxation experiments were performed at varying strains to explore the strain-dependence of the viscoelastic response. The proposed relaxation function successfully fit the experimental tensile stress-relaxation response, with R2=0.970±0.019 at 1% strain and R2=0.992±0.007 at 2% strain. The predicted cyclical response agreed well with experimental measurements, particularly for the dynamic modulus at various frequencies. The relaxation function, measured from 2% to 10% strain, was found to be strain dependent, indicating that cartilage is nonlinearly viscoelastic in tension. Under dynamic loading, the tensile modulus at 10Hz was ∼2.3 times the value of the equilibrium modulus. In contrast, the dynamic stiffening ratio in unconfined compression was ∼24. The energy dissipation in tension was found to be significantly smaller than in compression (dynamic phase angle of 16.7±7.4deg versus 53.5±12.8deg at 10−3Hz). A very strong linear correlation was observed between the dynamic tensile and dynamic compressive moduli at various frequencies (R2=0.908±0.100). The tensile response of cartilage is nonlinearly viscoelastic, with the relaxation response varying with strain. A proposed constitutive relation for the tensile response was successfully validated. The frequency response of the tensile modulus of cartilage was reported for the first time. Results emphasize that fluid-flow dependent viscoelasticity dominates the compressive response of cartilage, whereas intrinsic solid matrix viscoelasticity dominates the tensile response. Yet the dynamic compressive modulus of cartilage is critically dependent upon elevated values of the dynamic tensile modulus.
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Couto Aguiar, Letícia, Luiz A. Melgaço N. Branco, Eduardo Chahud, Francisco Antonio Rocco Lahr, André L. Christoforo, Rosane A. G. Battistelle, and Tulio Hallak Panzera. "Influence of Time Evolution in the Modulus of Elasticity of Concrete Reinforced by Carbon Fibers." Advanced Materials Research 1088 (February 2015): 640–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.640.
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The modulus of elasticity is an important property for the behavior analysis of concrete structures. This research evaluated the strain difference between concrete specimens with and without the application of laminate carbon fiber composites as well as the variation time, in months, of the axial strength compression and modulus of elasticity. Through the experimental results, it is concluded that increases in compressive strength and modulus of elasticity are more significant in the specimens without reinforcement.
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Adhikary, Partho, Md Arifuzzaman, and Emamul Kabir. "Compressive Properties of Expanded Perlite Based Particulate Composite for the Application in Building Insulation Board." Journal of Engineering Advancements 01, no. 01 (April 2020): 01–05. http://dx.doi.org/10.38032/jea.2020.01.001.
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In this paper, expanded perlite based particulate composites for the application in building insulation board are studied for compressive behaviour. Composites with a density range from 0.452 to 0.640 g/cm3 are manufactured using floatation method by varying binder content (sodium silicate solution and corn starch as binder) and the degree of compaction. Compressive strength and modulus are investigated based on two manufacturing parameters (i.e. Compaction ratio and Water/SSS ratio) and the density of the composites. Compressive strength and modulus were found to be linearly dependent on the density however the trend for compressive strength and modulus were found to be different. The change of compressive modulus with respect to increasing density is found to be different for different compaction ratio which is not significant in the case of compressive strength. The range of specific compressive strength of the composites from 4.27 to 5.08 MPa/(g/cm3) was found to be suitable for the building insulation board application when compared with existing literature.
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Joshi, Abhijeet, Samir Mehta, Edward Vresilovic, Andrew Karduna, and Michele Marcolongo. "Nucleus Implant Parameters Significantly Change the Compressive Stiffness of the Human Lumbar Intervertebral Disc." Journal of Biomechanical Engineering 127, no. 3 (January 31, 2005): 536–40. http://dx.doi.org/10.1115/1.1894369.
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Nucleus replacement by a synthetic material is a recent trend for treatment of lower back pain. Hydrogel nucleus implants were prepared with variations in implant modulus, height, and diameter. Human lumbar intervertebral discs (IVDs) were tested in compression for intact, denucleated, and implanted condition. Implantation of nucleus implants with different material and geometric parameters into a denucleated IVD significantly altered the IVD compressive stiffness. Variations in the nucleus implant parameters significantly change the compressive stiffness of the human lumbar IVD. Implant geometrical variations were more effective than those of implant modulus variations in the range examined.
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Li, Zeng Feng, Chen Wu, Gang Chen, Ping Tan, Shao Yang Zhao, Yuan Ge, and Jin Gou Yin. "Fabrication and Compressive Properties of Titanium Foam for Bone Implant Applications." Key Engineering Materials 770 (May 2018): 126–31. http://dx.doi.org/10.4028/www.scientific.net/kem.770.126.
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In order to meet the requirements for the purpose of biological implant materials, analyzes the matching requirements of the compatibility and mechanical properties of titanium foam biological; by powder metallurgy method, using TiH2 powder as raw material, using ammonium bicarbonate as pore forming agent, preparation of titanium foam. The influences of pore forming agent content and particle size, sintering temperature and holding time on the pore structure, pore distribution, pore size and compressive properties of foam titanium were discussed in detail. The results show that with the increase of the sintering temperature and prolonging holding time, titanium foam compressive yield strength and modulus increased; with the increase of the content of pore forming agent, titanium foam compression yield strength and Young's modulus decreased. The preparation of a porosity of 48% ~ 77%, pore size between 300 ~ 500 m, foam pore structure and pore size in micron level through three-dimensional pore, pore size of bio materials meet the requirements. The compressive strength is 98~186MPa, and the young's modulus is 1.6 ~ 6.8 GPa, which matches the strength and the modulus of elasticity of biological implants.
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Hwang, Jae Jung, Tadaharu Adachi, and Wakako Araki. "Time-Temperature Dependence of Compressive Behavior of Polypropylene Foams." Key Engineering Materials 345-346 (August 2007): 153–56. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.153.
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The time-temperature dependence of the compressive behavior of polypropylene (PP) foam was investigated to make predictions about what sort of behavior for wide ranges of temperature and strain rate. Compressive stress relaxation tests were conducted at 213 K and 373 K. Compression tests were also conducted. The strain rate was 2×10-3 1/s at 213 K and 373 K. The compressive stress-strain curves were roughly linear and dependent on temperature until the maximum stress was reached. The maximum stress occurred at 5% strain regardless of temperature. The plateau stresses decreased as temperature increased. By plotting compressive behavior of the PP foam at the master curve of the stress relaxation modulus, its temperature dependence could be explained by the thermo-viscoelastic properties. Therefore, the behavior of PP foam at different strain rates could be approximately predicted from the stress relaxation modulus with the timetemperature equivalence principle.
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Feng, Yan Feng, Tian Hong Yang, Hua Wei, Hua Guo Gao, and Zhe Zhang. "Research of Inclination Angle Effect on Joint Rock Macromechanical Parameters." Materials Science Forum 704-705 (December 2011): 1089–94. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.1089.
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The joint of rock mass influences and controls the rock mass intensity, deformation characteristics and instability failure in the rock engineering to a great extent. Using the similar material simulation is of different inclination angle of non-penetration jointing and non-jointing rock mass, through using rigid servo compression machine to carry uniaxial compression test, we get a nearly same trend of joint rock mass stress-strain curve of different angle, the curve of inclination angle of 45 is analyzed, the test result shows that the compressive strength first decreases and then increases gradually with the increase of rock inclination angle. The compression intensity is its minimum when of the inclination angle of 45°, and the deformation modulus first decreases and then increases, but deformation modulus of 30° is its minimum. In addition, through the use of developed RFPA2D system to simulate on trial uniaxial compression value based on microscopic damage mechanics, we get the conclusion that the numerical analysis and test result is fitting approximately, it is validated that the numerical model can simulate joint rock well. Keywords: joint rock mass, inclination angle, uniaxial compression, compressive intensity, deformation modulus
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Wan, Fan, Shixiang Zhao, Rongjun Liu, Changrui Zhang, and Thomas J. Marrow. "In situ Observation of Compression Damage in a Three-Dimensional Braided Carbon Fiber Reinforced Carbon and Silicon Carbide (C/C-SiC) Ceramic Composite." Microscopy and Microanalysis 24, no. 3 (June 2018): 227–37. http://dx.doi.org/10.1017/s1431927618000351.
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AbstractDeformation and mechanical damage in a three-dimensional braided carbon fiber reinforced carbon and silicon carbide ceramic composite, subjected to compressive loading, has been studied in situ by laboratory X-ray computed tomography. Dimensional change was measured and damage visualized by digital volume correlation analysis of tomographs. Cracks nucleated from defects within the fiber bundles and tended to propagate along the fiber bundle/matrix interface. For longitudinal compression, parallel to the fiber bundles, the initial elastic modulus decreased with increasing compressive strain while significant transverse tensile strains developed due to distributed cracking. For transverse compression, perpendicular to the fiber bundles, the compressive elastic modulus was effectively constant; the tensile strains developed along the fiber direction were small, whereas macroscopic fracture between the fiber bundles caused very large bulk tensile strain perpendicular to the loading. The observations suggest that the mechanical strength might be improved through control of pre-existing defects and application of stitch fibers in the transverse direction.
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Chen, Li Shun, Xiao Chen, Jian Tong Xu, and Zhong Yang. "Research on Alkali-Activator and its Effects on Mechanical Properties of Slag-Based Geopolymer at early Age." Applied Mechanics and Materials 556-562 (May 2014): 399–403. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.399.
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This report studied the influence of effects such as type, modulus, dosage of the alkali-activator on mechanical properties of slag-based geopolymer. The analyzing results indicate that compare to the Na2SiO3, K2SiO3has significant activate effects on slag-based geopolymer. The modulus and dosage have obvious significance on early compression strength of slag-based geopolymer. With the increase of modulus, its early compression strength has apparent increase. With the increase of dosage, its early compression strength increase firstly and then decrease. When the dosage is 12%, the compression strength of the material is highest. The change of modulus and dosage of the alkali-activator has little influence on flexural strength of slag-based geopolymer. With the increase of dosage, its ratio of flexural to compressive strength has a downward trend. And the material brittleness addition.
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Allameh-Haery, Haleh, Erich Kisi, and Thomas Fiedler. "Novel cellular perlite–epoxy foams: Effect of density on mechanical properties." Journal of Cellular Plastics 53, no. 4 (June 6, 2016): 425–42. http://dx.doi.org/10.1177/0021955x16652110.
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A novel type of economical lightweight foam with density from 0.15 to 0.45 g/cm3 was made from a high volume fraction of expanded volcanic glass (perlite) in an epoxy matrix. The compressive strength, effective elastic modulus, and modulus of toughness of the foams all increased with the foam density. The strength increased linearly, peaking at 1.7 MPa whereas the effective elastic modulus and modulus of toughness increased at parabolically increasing and decreasing rates, respectively. The specific compressive stress of the newly developed foam in the density range of 0.3–0.44 g/cm3 is comparable with foams made from alumina, aluminium–silicon carbide, closed cell phenolic resin, and closed cell polypropylene. Post-test SEM observations coupled with photogrammetry during the tests revealed three different failure modes: longitudinal splitting, shear failure, and compression failure were present over the whole density range. The material was found to be a good candidate for the stiffening cores within sandwich panels.
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Kaboré, P., H. Jaafar, H. Wang, W. Hamad, and A. P. Wang. "Modelling Radial Compressive Modulus in Wound Rolls." Measurement and Control 40, no. 7 (September 2007): 207–10. http://dx.doi.org/10.1177/002029400704000702.
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MITSUMATA, TETSU, KENTA FURUKAWA, ETIENNE JULIAC, KENJI IWAKURA, and KIYOHITO KOYAMA. "COMPRESSIVE MODULUS OF FERRITE CONTAINING POLYMER GELS." International Journal of Modern Physics B 16, no. 17n18 (July 20, 2002): 2419–25. http://dx.doi.org/10.1142/s0217979202012451.
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The mechanical properties of magnetic gel have been investigated. Magnetic gels, which consist of finely dispersed powder of barium ferrite ( BaFe 12 O 19) and poly vinyl alcohol (PVA), have been synthesized. The diameter of barium ferrite is less than 45 μm. The magnetic gels varying with ferrite concentration, crosslinking densities were prepared by mixing 10 wt.% PVA aqueous solution and barium ferrite using glutaraldehyde as a crosslinking agent in the presence of HCl. The diameter of barium ferrite is large enough to have a permanent magnetic moment. We applied a 10 kOe magnetic field in order to saturate the magnetic moment of barium ferrite. After magnetization, the compressive modulus was estimated with an ultrasonic method in order to find the influence of magnetization. Ultrasonic measurements were carried out using burst waves at 10 MHz and 295.5 K. The modulus of magnetized gel was found to depend on the concentration of magnetic substance, the crosslinking density, and the degree of swelling. It was clear that the modulus of magnetized gel was higher than the gel without magnetization for all samples. The change in modulus to the initial modulus ΔM′/M′o for 10 wt.% and 15 wt.% of ferrite concentration was about 0.28% and 0.4% in a lower density region, respectively. Moreover, the change in modulus ΔM′/M′o was constant in a lower density region however it strongly depends on the density in a higher density region. When the stress direction is perpendicular to the magnetization, the change in modulus increased. On the contrary, the change in modulus decreased when the stress direction is parallel to the magnetization. As increasing the density, the distance between magnetic substances become short and therefore the magnetic interaction is more significant in a higher density region.
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Zhang, Yan Nian, and Jun Xie. "Compressive Behaviour of Laminated Neoprene Bridge Bearing Pads under Thermal Aging Condition." Materials Science Forum 972 (October 2019): 118–22. http://dx.doi.org/10.4028/www.scientific.net/msf.972.118.
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The present study was conducted to obtain a better understanding of the variation rule of mechanical properties of laminated neoprene bridge bearing pads under thermal aging condition using compression tests. A total of 5 specimens were processed in a high-temperature chamber. After that, the specimens were tested subjected to axial load. The parameter mainly considered time of thermal aging processing for specimens. The results of compression tests show that the specimens after thermal aging processing are more probably brittle failure than the standard specimen. Moreover, the exposure of steel plate, cracks and other failure phenomena are more serious than the standard specimen. The compressive capacity, ultimate compressive strength, compressive elastic modulus of the laminated neoprene bridge bearing pads decreased dramatically with the increasing in the aging time of thermal aging processing. The attenuation trends of ultimate compressive strength, compressive elastic modulus of laminated neoprene bridge bearing pads under thermal aging condition accord with power function. The attenuation models are acquired by regressing data of experiment with the least square method. The attenuation models conform to reality well which shows that this model is applicable and has vast prospect in assessing the performance of laminated neoprene bridge bearing pads under thermal aging condition.
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Urbański, Marek. "Compressive Strength of Modified FRP Hybrid Bars." Materials 13, no. 8 (April 17, 2020): 1898. http://dx.doi.org/10.3390/ma13081898.
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A new type of HFRP hybrid bars (hybrid fiber reinforced polymer) was introduced to increase the rigidity of FRP reinforcement, which was a basic drawback of the FRP bars used so far. Compared to the BFRP (basalt fiber reinforced polymer) bars, modification has been introduced in HFRP bars consisting of swapping basalt fibers with carbon fibers. One of the most important mechanical properties of FRP bars is compressive strength, which determines the scope of reinforcement in compressed reinforced concrete elements (e.g., column). The compression properties of FRP bars are currently ignored in the standards (ACI, CSA). The article presents compression properties for HFRP bars based on the developed compression test method. Thirty HFRP bars were tested for comparison with previously tested BFRP bars. All bars had a nominal diameter of 8 mm and their nonanchored (free) length varied from 50 to 220 mm. Test results showed that the ultimate compressive strength of nonbuckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. In addition, the modulus of elasticity under compression does not change significantly compared to the modulus of elasticity under tension. A linear correlation of buckling load strength was proposed depending on the free length of HFRP bars.
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Huang, Dongmei, Xikun Chang, Yunliang Tan, Kai Fang, and Yanchun Yin. "From rock microstructure to macromechanical properties based on fractal dimensions." Advances in Mechanical Engineering 11, no. 3 (March 2019): 168781401983636. http://dx.doi.org/10.1177/1687814019836363.
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Basic rock mechanical parameters, that is, the uniaxial compressive strength σc and elastic modulus E, have close relationships with the fractal dimension and inhomogeneity. Scanning electronic microscopy and fractal dimension calculations are applied to four different rock types (mudstone, sandstone, limestone, and basalt) in order to investigate the relationships between the rock mechanical properties, fractal dimensions, and homogeneity. The results show that the fractal dimension of each rock type fluctuates as the scanning electronic microscopy magnification increases. Rocks with different uniaxial compressive strength and elastic modulus values possess different self-similarity properties, and when the uniaxial compressive strength or elastic modulus increases, the fractal dimension of the rock microstructure decreases. The rock homogeneity is consistent with the fractal dimension, that is, the higher the homogeneity is, the larger the fractal dimension. Generally, homogeneity refers to the macroscale, and fractal dimension refers to the microscale. Overall, this research provides an innovative and effective approach for researching the mechanical behavior of rocks through a combination of uniaxial compression tests, homogeneity, and fractal dimensions.
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Huang, Jia’ning, Ruiduo Li, Song Yin, and Pengfei Liu. "Experimental Study on the High-Temperature Shear Performance of Asphalt Mixtures." Advances in Materials Science and Engineering 2021 (September 9, 2021): 1–11. http://dx.doi.org/10.1155/2021/6428018.
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The influence of temperature on the shear performance of asphalt mixtures and the feasibility of using the deformation strength as an index of the high-temperature shear performance of these mixtures were explored in this study. Taking AC-13C and AC-20C asphalt mixtures as the research objects, uniaxial compression, rutting, deformation strength, and uniaxial static load creep tests were carried out at temperatures 40°C, 45°C, 50°C, 55°C, and 60°C. The correlations between the deformation strength and modulus of resilience, compressive strength, dynamic stability, and stiffness of the asphalt mixtures were studied. The test results show that the influence of temperature on the compressive strength, resilience modulus, and deformation strength of the asphalt mixtures decreases significantly as the temperature increased, and the rutting deformation of the two kinds of asphalt mixtures increased as the temperature increased. Strong correlations exist between the deformation strength and the modulus of resilience, the compressive strength, and the dynamic stability of asphalt mixtures, so the deformation strength can be used as an evaluation index of the high-temperature shear performance of asphalt mixtures.
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Li, Shuguang, Yanxia Feng, Mengyuan Wang, and Yingcheng Hu. "Mechanical Behavior of Natural Fiber-Based Bi-Directional Corrugated Lattice Sandwich Structure." Materials 11, no. 12 (December 18, 2018): 2578. http://dx.doi.org/10.3390/ma11122578.
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In this study, 11 kinds of composite material were prepared, and the compression behavior of a bi-directional corrugated lattice sandwich structure prepared using jute fiber and epoxy resin was explored. The factors affecting the mechanical behavior of single and double-layer structures were studied separately. The results shows that the fiber angle, length-to-diameter ratio of the struts, and the type of fiber cloth have the most significant influence on the mechanical behavior of the single-layer lattice structure when preparing the core layer. When the fiber angle of the core layer jute/epoxy prepreg is (90/90) the compressive strength and Young’s modulus are 83.3% and 60.0% higher than the fiber angle of (45/45). The configuration of the core and the presence of the intermediate support plate of the double-layer structure have a large influence on the compression performance of the two-layer structure. After the configuration was optimized, the compressive strength and Young’s modulus were increased by 40.0% and 28.9%, respectively. The presence of the intermediate support plate increases the compressive strength, and Young’s modulus of the double-layer structure by 75.0% and 26.6%, respectively. The experimental failure is dominated by the buckling, fracture, and delamination of the core struts.
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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.
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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.
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Cao, Jia Yun, Xiao Min Zhang, Hong Bo Chen, and Yu Jiang. "Simulation Analysis of Influence of Different Parameters on Sliding Failure and Compressive Failure of Carbon Fiber Reinforced Polymer." Advanced Materials Research 1166 (September 27, 2021): 13–24. http://dx.doi.org/10.4028/www.scientific.net/amr.1166.13.
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Carbon Fiber Reinforced Polymer (CFRP) is an anisotropic material with outstanding tensile strength in the direction of axial but low compressive strength in the direction of radial, so the radial compressive failure and sliding failure are easy to occur in the practical application of compression and hanging wires. In this paper, the influence of different parameters on radial compressive failure and sliding failure is studied. The finite element method is used to simulate and analyze the CFRP and wedge clamp to find optimum condition parameters to make the CFRP neither sliding failure nor radial compressive failure. The parameters are as follows: interference between the CFRP and the inner wedge, friction coefficient between the CFRP and the inner wedge, angle of the wedge, inner wedge material elastic modulus. The results show that the most appropriate parameter is: the interference between 0.0236mm and 0.0252mm, the friction coefficient between 0.194 and 0.206, the wedge angle is greater than 1.75° and the elastic modulus of wedge material has little influence on the compressive failure and slippage failure of the CFRP.
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Cui, Hong Zhi, and Feng Xing. "The Study of Mechanical Properties of Structural Lightweight Concrete." Advanced Materials Research 97-101 (March 2010): 1620–23. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1620.
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Many investigations have been conducted on compressive strength of lightweight aggregate concretes (LWAC), but there are few experimental studies on the relationship between compressive strength, bond strength and elastic modulus of LWAC. In this paper, the specimens of twenty kinds of LWACs with different mix proportions were made. Properties of compressive strength, bond strength and modulus of elasticity of the LWACs were tested. Based on the testing resulting, equations for relationship between bond strength and compressive strength of the LWAC were established. For LWAC modulus of elasticity, the experimental results of this study can fit well with predicted equation of ACI 318
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Xie, Nan, Jie Ouyang, Bing Li, and Jing Hui Lu. "Experimental Research on Mechanical Properties of the early-Age Shotcrete." Applied Mechanics and Materials 90-93 (September 2011): 2188–92. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2188.
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Abstract. The compressive strength and elastic modulus of early-age shotcrete have important influence on the safety of tunnel during construction period. In order to investigate the laws of the mechanical properties of early-age shotcrete, experiments on the compressive strength and elastic modulus of early-age shotcrete with two different mixes used frequently on construction sites were carried out. The results show that the compressive strength and elastic modulus of shotcrete develop fairly rapidly and especially the development of elastic modulus of shotcrete is faster than that of ordinary concrete. There is an exponential relationship between the compressive strength and time as well as the elastic modulus development and time. Simultaneously their formulas were derived. The research results of this paper are not only helpful to understand the laws of the mechanical properties of early-age shotcrete, but also provide some reference for the reliability analysis of tunnel under construction.
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Huang, Shiyuan, Junjie Wang, Zhenfeng Qiu, and Kai Kang. "Effects of Cyclic Wetting-Drying Conditions on Elastic Modulus and Compressive Strength of Sandstone and Mudstone." Processes 6, no. 12 (November 22, 2018): 234. http://dx.doi.org/10.3390/pr6120234.
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The influence of water on the mechanical properties of rock is vital for determining the rock stability when subjected to changes of water conditions. In this paper, a series of uniaxial compression tests were conducted to investigate effects of cyclic wetting and drying on the mechanical properties of sandstone and mudstone collected from Chongqing city, China. The results showed that both elastic modulus and uniaxial compressive strength of sandstone and mudstone were reduced by wetting and drying cycles, and that the degradation rate of the two mechanic parameters of mudstone was always larger than sandstone. The parameters, including water adsorption, degradation degree of elastic modulus, degradation degree of uniaxial compressive strength, increase with the increase of the wetting-drying cycles (N). The relationship between these three parameters and the value of N + 1 could be well fitted by logarithmic curves. The average degradation degree was also used to describe the degradation of per time wetting-drying cycles. It is found that the average degradation degree of elastic modulus and uniaxial compressive strength decrease with the increase of wetting-drying cycles. Moreover, the relationships between the mechanical properties and the porosity are presented, which can be fitted by linear curves. In the cyclic wetting-drying process, the elastic modulus and the uniaxial compressive strength decreased with the porosity increasing, and the degradation rates of sandstone mechanic parameters were higher than those of mudstone.
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Hasan, Muttaqin, Saiful Husin, and Cut Nursaniah. "Mechanical Properties of Concrete in Compression Exposed to Sulfuric Acid." Key Engineering Materials 711 (September 2016): 302–9. http://dx.doi.org/10.4028/www.scientific.net/kem.711.302.
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This paper presents the degradation of compressive strength and stiffness of concrete after immersed in 2,5 % sulfuric acid solution. The durations of immersion are 0, 3, 7, 14, and 28 days. After the immersion, ultrasonic pulse velocity and compression tests are performed on the specimens. The relative dynamic elastic modulus, compressive strength and its initial stiffness decrease with increasing the duration of immersion, as a result of the increasing microcracks in the concrete. The strain at peak stress increases with increasing the duration of immersion. The degradation of compressive strength, the degradation of initial stiffness and the value of strain at peak stress of damaged concrete are formulated as a function of relative dynamic elastic modulus. A simple mathematical expression for stress-strain relationship of concrete damaged by sulfuric acid is proposed and stress-strain curves at different level of damage are compared.
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Reiterman, Pavel. "Static Modulus of Elasticity of Concrete." Materials Science Forum 824 (July 2015): 151–54. http://dx.doi.org/10.4028/www.scientific.net/msf.824.151.
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Present paper deals with the experimental investigation of static modulus of elasticity of hardened concrete and its relation to compressive strength of concrete. Based on the number of measurement was derived expression of dependence of modulus of elasticity on compressive strength of concrete which was determined using cubic specimens; modulus of elasticity was measured using prismatic specimens of dimensions 100x100x400 mm. Studied concrete mixtures present commonly used concrete of all established strength classes.
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Shepherd, D. E. T., and B. B. Seedhom. "A technique for measuring the compressive modulus of articular cartilage under physiological loading rates with preliminary results." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 211, no. 2 (February 1, 1997): 155–65. http://dx.doi.org/10.1243/0954411971534278.
Full textAbstract:
This paper describes a technique and apparatus for measuring the compressive modulus of articular cartilage under physiological loading rates. The compressive modulus is the most relevant property to the primary function of articular cartilage i.e. load carriage. It has been determined previously from measurement of cartilage deformation under slow or almost static loading conditions. The modulus was based on deformations occurring 2 s after the initial application of load which greatly reduces its relevance since in physiological conditions joint loading occurs within 10-150 ms. Five human knee joints have been used to test the apparatus before a major study is undertaken. The preliminary results from these joints showed that the compressive modulus of articular cartilage measured within physiological loading time intervals was much greater than previously reported. The compressive modulus at 20 ms was in the range 4.4-27 MPa and was between 32 and 75 per cent greater than its value obtained at 2 s after loading.
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Saheb, Nouari. "Compressive Behavior of Spark Plasma Sintered CNT Reinforced Al2124 and Al6061 Nanocomposites." Advanced Materials Research 652-654 (January 2013): 33–37. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.33.
Full textAbstract:
In the present study, compressive behavior of CNT reinforced Al2124 and Al6061 nanocomposites was investigated. The powders were sonicated for 30 minutes then ball milled at 200 rpm for 1 hour under argon environment. The ball milled slurry was dried and again was milled under same conditions for 15 min to disperse the agglomerated particles. The prepared powders were spark plasma sintered at 35 MPa and 450oC. Sintered specimens with final dimensions of 6 mm diameter and 12 mm length were used as standard specimens for compression tests carried out at a compression rate of 0.5 mm/min. The effect of CNT addition on the compressive modulus, percentage compression, and compressive strength was investigated.