Journal articles: 'Load-transfer curves'

1

Bohn, Cécilia, Alexandre Lopes dos Santos, and Roger Frank. "Development of Axial Pile Load Transfer Curves Based on Instrumented Load Tests." Journal of Geotechnical and Geoenvironmental Engineering 143, no. 1 (January 2017): 04016081. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001579.

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Nanda, S., and N. R. Patra. "Theoretical Load-Transfer Curves along Piles Considering Soil Nonlinearity." Journal of Geotechnical and Geoenvironmental Engineering 140, no. 1 (January 2014): 91–101. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0000997.

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Zhu, Hong, and Ming-Fang Chang. "Load Transfer Curves along Bored Piles Considering Modulus Degradation." Journal of Geotechnical and Geoenvironmental Engineering 128, no. 9 (September 2002): 764–74. http://dx.doi.org/10.1061/(asce)1090-0241(2002)128:9(764).

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Kataoka, L. T., and T. N. Bittencourt. "Numerical and experimental analysis of time-dependent load transfer in reinforced concrete columns." Revista IBRACON de Estruturas e Materiais 7, no. 5 (October 2014): 747–74. http://dx.doi.org/10.1590/s1983-41952014000500003.

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A study was conducted to assess the influence of the steel reinforcement ratio in concrete columns on their properties of creep and shrinkage. Experimental tests and three-dimensional finite element-based simulations of the experimental curves from plain concrete cylinders and plain concrete columns derived by curve fitting were performed using the ACI 209 model available in DIANA 9.3. Columns with longitudinal reinforcement ratios of 0%, 1.4% and 2.8%, loaded to 30% and 40% of their 7-day compressive strength, were investigated. The results indicated that numerical simulation does not predict experimental data for a long period. However, simulations fitted with experimental curves derived from plain concrete columns presented values close to those of experimental data for 91 days.

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Pereira Fernandes, David Jorge, and
António Viana da Fonseca. "Definition of load transfer curves of piles in granitic residual soil." Geotecnia 130 (March 2014): 79–99. http://dx.doi.org/10.24849/j.geot.2014.130.04.

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Zheng, Ying Jie, Xue Dai, and Lian Xiang Li. "Analysis of an O-Cell Pile Test in Jinan with FEM." Applied Mechanics and Materials 170-173 (May 2012): 33–36. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.33.

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In order to promote the experience of applying O-cell pile test to determine the behaviors of integral pile in Jinan, a case of O-cell pile test in Jinan was analyzed with proposed approach. The pile-soil system was simulated with FEM. The resistance parameters of piles, the load-displacement curves and the ultimate bearing capacity of integral pile were determined. Comparing with results obtained from load transfer method, it is found that the p-s curve of integral pile obtained from load transfer method is conservative.

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7

Mostafa, Yasser E., and M. Hesham El Naggar. "Dynamic analysis of laterally loaded pile groups in sand and clay." Canadian Geotechnical Journal 39, no. 6 (December 1, 2002): 1358–83. http://dx.doi.org/10.1139/t02-102.

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Pile foundations supporting bridge piers, offshore platforms, and marine structures are required to resist not only static loading but also lateral dynamic loading. The static py curves are widely used to relate pile deflections to nonlinear soil reactions. The p-multiplier concept is used to account for the group effect by relating the load transfer curves of a pile in a group to the load transfer curves of a single pile. Some studies have examined the validity of the p-multiplier concept for the static and cyclic loading cases. However, the concept of the p-multiplier has not yet been considered for the dynamic loading case, and hence it is undertaken in the current study. An analysis of the dynamic lateral response of pile groups is described. The proposed analysis incorporates the static py curve approach and the plane strain assumptions to represent the soil reactions within the framework of a Winkler model. The model accounts for the nonlinear behaviour of the soil, the energy dissipation through the soil, and the pile group effect. The model was validated by analyzing the response of pile groups subjected to lateral Statnamic loading and comparing the results with field measured values. An intensive parametric study was performed employing the proposed analysis, and the results were used to establish dynamic soil reactions for single piles and pile groups for different types of sand and clay under harmonic loading with varying frequencies applied at the pile head. "Dynamic" p-multipliers were established to relate the dynamic load transfer curves of a pile in a group to the dynamic load transfer curves for a single pile. The dynamic p-multipliers were found to vary with the spacing between piles, soil type, peak amplitude of loading, and the angle between the line connecting any two piles and the direction of loading. The study indicated the effect of pile material and geometry, pile installation method, and pile head conditions on the p-multipliers. The calculated p-multipliers compared well with p-multipliers back-calculated from full scale field tests.Key words: lateral, transient loading, nonlinear, pilesoilpile interaction, py curves, Statnamic.

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Tak Kim, Byung, Nak-Kyung Kim, Woo Jin Lee, and Young Su Kim. "Experimental Load–Transfer Curves of Laterally Loaded Piles in Nak-Dong River Sand." Journal of Geotechnical and Geoenvironmental Engineering 130, no. 4 (April 2004): 416–25. http://dx.doi.org/10.1061/(asce)1090-0241(2004)130:4(416).

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Kim, Hyeong Joo, Jose Leo C. Mission, and Il Sang Park. "Analysis of static axial load capacity of single piles and large diameter shafts using nonlinear load transfer curves." KSCE Journal of Civil Engineering 11, no. 6 (November 2007): 285–92. http://dx.doi.org/10.1007/bf02885899.

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10

Kwon, Oh Sung, Yongkyu Choi, Ohkyun Kwon, and Myoung Mo Kim. "Comparison of the Bidirectional Load Test with the Top-Down Load Test." Transportation Research Record: Journal of the Transportation Research Board 1936, no. 1 (January 2005): 108–16. http://dx.doi.org/10.1177/0361198105193600113.

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For the past decade, the Osterberg testing method (O-cell test) has been proved advantageous over the conventional pile load testing method in many aspects. However, because the O-cell test uses a loading mechanism entirely different from that of the conventional pile loading testing method, many investigators and practicing engineers have been concerned that the O-cell test would give inaccurate results, especially about the pile head settlement behavior. Therefore, a bidirectional load test using the Osterberg method and the conventional top-down load test were executed on 1.5-m diameter cast-in-place concrete piles at the same time and site. Strain gauges were placed on the piles. The two tests gave similar load transfer curves at various depth of piles. However, the top-down equivalent curve constructed from the bidirectional load test results predicted the pile head settlement under the pile design load to be approximately one half of that predicted by the conventional top-down load test. To improve the prediction accuracy of the top-down equivalent curve, a simple method that accounts for the pile compression was proposed. It was also shown that the strain gauge measurement data from the bidirectional load test could reproduce almost the same top-down curve.

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11

Piekarczuk, A. "Test-supported numerical analysis for evaluation of the load capacity of thin-walled corrugated profiles." Bulletin of the Polish Academy of Sciences Technical Sciences 65, no. 6 (December 1, 2017): 791–98. http://dx.doi.org/10.1515/bpasts-2017-0087.

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Abstract The paper concentrates on a quantitative evaluation of the load capacity of thin-walled, curved steel profiles used as arched roofs in building structures. Corrugation of a profile surface formed by cold rolling changes its load capacity as compared to thin-walled profiles. The paper presents a comparative evaluation of the influence of a sample profile corrugation on its ability to transfer internal forces. The results of the study are presented as limit curves describing load capacity at simultaneous bending and compression. The analysis was conducted using a numerical computational method supported by a study of elements in natural scale. The paper presents a methodology of test-supported calculations and guidelines for practical use by designers.

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12

Gomes Filho, Francisco Vladson Cardins, and Alfran Sampaio Moura. "Proposal for considering the group effect in the prediction of settlements in pile groups through load transfer methods." Soils and Rocks 44, no. 2 (June 18, 2021): 1–8. http://dx.doi.org/10.28927/sr.2021.061320.

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When designing a foundation project, it is necessary to ensure that all the elements meet both ultimate and serviceability limit states, which call for predictions of settlement and load capacity. The load transfer methods are a widely used alternative to estimate the load-settlement ratio of piles in the design of foundation projects. However, traditional load transfer methods do not consider the interactive effects between the elements in pile groups. This study proposes changes to the load transfer curves developed by Bohn et al. (2016), aiming to incorporate the group effect in the analysis of load-settlement relationships in pile groups. Comparisons between the predicted settlements obtained using the proposed method and the results of load tests performed by Dai et al. (2012) in Jiangsu, China, showed that the modifications proposed in this study agreed well with the experimental results for most of the analyzed groups.

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13

Xu, Hong-Fa, Ji-Xiang Zhang, Xin Liu, Han-Sheng Geng, Ke-Liang Li, and Yin-Hao Yang. "Analytical Model and Back-Analysis for Pile-Soil System Behavior under Axial Loading." Mathematical Problems in Engineering 2020 (March 19, 2020): 1–15. http://dx.doi.org/10.1155/2020/1369348.

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The interaction mechanism between piles and soils is very complicated. The load transfer function is generally nonlinear and is affected by factors such as pile side roughness, soil characteristics, section depth, and displacement. Therefore, it is difficult to solve the pile-soil system based on load transfer function. This paper presents a new method to study the soil-pile interaction problem with respect to axial loads. First, the shapes of the axial force-displacement curves at different depths and the displacement distribution curves along pile axis at different pile-top displacements were analyzed. A simple exponential function was taken as relationship model to express the relationship curves between two distribution functions of axial force and displacement along pile shaft obtained by using the geometric drawing method. Second, a new analytical model of the pile-soil system was established based on the basic differential equations for pile-soil load transfer theory and the relationship model and was used to derive the mathematical expressions on the distribution functions of the axial force, the lateral friction, and the displacement along pile shaft and the load transfer function of pile-side. We wrote the MATLAB program for the analytical model to analyze the influence laws of the parameters u and m on the pile-soil system characteristics. Third, the back-analysis method and steps of the pile-soil system characteristics were proposed according to the analytical model. The back-analysis results were in good agreement with the experimental results for the examples. The analysis model provides an effective way for the accurate design of piles under axial loading.

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Kim, Young Shin, Yu Jun Song, and Euy Sik Jeon. "Numerical and Experimental Analysis of Torsion Springs Using NURBS Curves." Applied Sciences 10, no. 7 (April 10, 2020): 2629. http://dx.doi.org/10.3390/app10072629.

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Torsion springs, which transfer power through the twisting of their coil, provide advantages such as module simplification and efficient use of space. The design of a torsion spring has been formulated, but it is difficult to determine the local behaviors of torsion springs according to actual load conditions. This study proposes a torsion-spring design method through finite element analysis (FEA) using nonuniform-rational-basis-spline (NURBS) curves. Through experimentation, the angle and displacement values for the actual spring load were converted into useable data. Torsion-spring displacement values were obtained via experimentation and converted into coordinates that may be expressed using NURBS curves. The results of these experiments were then compared to those obtained via FEA, and the validity of this method was thereby verified.

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15

Wang, Jingjing, Lihua Lyu, Jing Guo, Xiaoqing Xiong, Ying Wang, and Fang Ye. "Axial Compression Properties of Special-Shaped 3D Tubular Woven Composites." AATCC Journal of Research 8, no. 2 (March 1, 2021): 18–25. http://dx.doi.org/10.14504/ajr.8.2.3.

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Axial compression properties of special-shaped 3D tubular woven composites with basalt fiber filament tows were studied. Special-shaped 3D tubular woven fabrics composites with three different thicknesses were woven on an ordinary loom and fabricated by the vacuum assisted resin transfer molding (VARTM) process. Load-displacement and energy-displacement curves were obtained from experimental tests. Results showed that for special-shaped 3D tubular woven composites, the load and energy absorption were greater with thickness and the compression property improved. Through the analysis of the mathematical equation and correlation coefficient of the load-displacement and energy-displacement relation, the fitting effect of the curves were good. The mathematical equation of the method could be used to simplify the functional relationship between load, energy, and displacement.

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16

Li, Xiao Bing, Jie Wei, Yi Pin Li, and Bei Zhu. "Normalized Numerical Analysis for Load-Displacement Curve of Uplift Pile in Soft Soil." Advanced Materials Research 446-449 (January 2012): 1462–67. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1462.

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On the basis of Hsiung’s normalization analysis method, the soil is assumed to be in accordance with the elastic-plastic model. Some normalized parameters are selected to normalize different load-displacement curves to a single one, which is obtained by using the parabolic load transfer function. At last, we get a regression formula of the single curve with the regression analysis method. By comparing the results of regression formula with the practical test data of projects, the fact that the calculation results of regression formula coincide well with test data show that this analysis method is correct and it can provide reference for the research and application of uplift pile.

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Li, Jin Hua. "Theory and Experiment Research on P-S Curve of Anchor in Soil." Advanced Materials Research 518-523 (May 2012): 6097–102. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.6097.

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Based on the shear displacement constitutive relationship of the interface between anchorage body and surrounding soil, the load transfer function method is applied to build a elastic-plastic space model. Accordingly the relationship between drawing force and displacement of prestressed anchor is analysed to acquie theoretical formula of P-S curve. The pullout test is carried out on six prestressed anchor in soil to get P-S curves. The experimental results agree quite well on the theoretical results.

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18

Shi, Guo Ping, and Jun Liang. "Total Transfer Capability Calculation Based on Static Load Model Using Real-Time Fault Recording Data." Applied Mechanics and Materials 303-306 (February 2013): 597–600. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.597.

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This paper proposes a method calculating TTC and critical voltage using static power model based on real-time recording data, traditional power system dispatching calculation doesn’t consider load model, which does not agree with the real, this paper compares TTC and critical voltage under different load model and P-V curves, on which load model has a strong influence, so load modeling is necessary based on real-time data and is significant for improving system stability. The simulations show necessity and suitability of the method.

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19

Li, Lin, Jingpei Li, De’an Sun, and Weibing Gong. "Semi-analytical approach for time-dependent load–settlement response of a jacked pile in clay strata." Canadian Geotechnical Journal 54, no. 12 (December 2017): 1682–92. http://dx.doi.org/10.1139/cgj-2016-0561.

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Mechanical behaviour of the soil around a jacked pile changes significantly during pile installation and subsequent consolidation. Hence, an axially loaded jacked pile exhibits apparent time-dependent bearing performance after pile installation. This paper presents a semi-analytical approach to predict the time-dependent bearing performance of an axially loaded jacked pile in saturated clay strata. The effects of pile installation and subsequent consolidation on the changes in mechanical properties of the surrounding soil are modeled by the cavity expansion theory and the radial consolidation theory, respectively. An exponential function–based load-transfer (t–z) curve is employed to describe the nonlinear behaviour of the pile–soil interface during pile loading. The evolutions of the three-dimensional strength and shear modulus of the surrounding soil are subsequently incorporated into the two model parameters of the proposed t–z curve to capture the time-dependent pile–soil interaction behaviour. The time-dependent elastic response of the soil outside the pile–soil interface is also considered in the proposed approach. With the proposed load-transfer curve, an incremental algorithm and a corresponding computational code are developed for assessing the time-dependent load–settlement response of a jacked pile. To verify the proposed semi-analytical approach, predictions of the time-dependent load–settlement curves are compared with the measured values from pile tests at two sites. The good agreement shows that the time-dependent bearing performance can be reasonably predicted by the proposed approach.

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20

Lyu, Lihua, Liming Zhu, Jingrui Cui, Jing Guo, and Fang Ye. "Bending Property of Honeycombed 3D Woven Composites with Quadrilateral Cross Section." AATCC Journal of Research 7, no. 2 (March 1, 2020): 7–12. http://dx.doi.org/10.14504/ajr.7.2.2.

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The delamination resistance and damage tolerance of traditional honeycomb composites are poor. To overcome these defects, 3D (three-dimensional) integrated woven composites of honeycomb structure were designed, and then manufactured using the vacuum assisted resin transfer molding process (VARTM), based on the 3D self-prepared fabrics used as reinforcements. The load-displacement curves, maximum bending load-velocity curves, and bar chart of energy absorption were determined experimentally and calculated by finite element simulation. The results showed good agreement between experimental and finite element simulation data. The correctness of the model was verified, so the model can be used to predict the mechanical properties of 3D integrated woven composites of honeycomb structure with quadrilateral cross section.

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21

Qi, Yong, Ci Mian Zhu, Shu Sheng Zhong, Fang Wang, and Yang Xiang. "Seismic Performance of Haunched Beam Transfer Structures of Frame-Supported Short-Leg Shearwall with Varied Ratio of Short-Leg Shearwall Section Height to Thickness." Advanced Materials Research 255-260 (May 2011): 2308–12. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2308.

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This paper deals with an experimental study on the seismic performance of haunched transfer beam structures with varied ratio of section height to thickness of short-leg shearwall (RHT). Based on the seismic tests of three 1:3-scaled specimens under low-frequency cyclic lateral load with constant vertical actions, the failure pattern, the hysteresis curves, the skeleton curves, the energy dissipation capacity, and the stiffness degradation laws of haunched transfer beam structures are investigated. The effects of different RHT (i.e., 5, 6 and 7) on the seismic performance of haunched transfer beam structures are emphasized and analyzed in detail. It is concluded that the rigidity of the structure is noticeable enhanced, the endogen force becomes more evenly distributed and the bearing is more rational with an increase of the RHT; the rationally designed haunched transfer beam structure has a good seismic behavior.

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Al-Manaseer, A. A., and D. V. Phillips. "Numerical study of some post-cracking material parameters affecting nonlinear solutions in RC deep beams." Canadian Journal of Civil Engineering 14, no. 5 (October 1, 1987): 655–66. http://dx.doi.org/10.1139/l87-096.

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This paper describes a numerical study of some of the quasi-material parameters which are used to define the post-cracking response in smeared crack models for the nonlinear finite element analysis of reinforced concrete. The two major effects studied were interface shear transfer and tension stiffening. The investigation was carried out on a solid deep beam using a nonlinear plane stress formulation. Parabolic isoparametric elements were used with a standard nonlinear solution procedure.The effect of the quasi-material parameters was found to be significant in predicting the behaviour of the deep beam. A sudden drop in the stress at the cracking load was found to be important in the tension stiffening model. Different values can lead to different solutions for load–deflection curves, ultimate loads, and crack patterns. Also it was found that a large reduction in shear modulus to account for interface shear transfer can affect the nonlinear solution and cause numerical problems when used with a gradual release tension stiffening model with no discontinuity at the cracking load. Key words: deep beams, finite element, load deflection, post-cracking, shear transfer, tension stiffening, ultimate load.

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23

Jiang, Jian Qing. "Bearing Capacity and Mechanical Behavior Experiment on Large Diameter-Expanding Pile." Advanced Materials Research 243-249 (May 2011): 457–60. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.457.

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Combined with the pile foundation engineering of a super-large highway bridge, vertical static loading test of pile with expanded diameter was carried out. The pile’s load-settlement curves, axial forces of the different pile’s section and the pile-soil interaction friction were obtained from the test. The load transfer mechanism and bearing behavior of the pile with expanded diameter under vertical load were studied. The results show that the ultimate load of the testing pile is more than 6000kN. The pile-soil interaction of the pile with expanded diameter behaviors as friction pile, and the bearing capacity of the segment with expanded diameter accounts for 40% of the ultimate load. These studies provide important references for similar projects.

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24

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.

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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.

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25

Wang, H., L. Z. Wang, Yi Hong, B. He, and R. H. Zhu. "Quantifying the influence of pile diameter on the load transfer curves of laterally loaded monopile in sand." Applied Ocean Research 101 (August 2020): 102196. http://dx.doi.org/10.1016/j.apor.2020.102196.

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26

Yaldirim, N., and R. G. Munro. "A new type of profile relief for high contact ratio spur gears." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 6 (June 1, 1999): 563–68. http://dx.doi.org/10.1243/0954406991522491.

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The second of a series of papers on the systematic approach to the profile relief design of both low contact ratio (LCR) and high contact ratio (HCR) spur gears and its effects on transmission error (TE) and tooth loads. Basics of the approach are given in the previous paper of the series. Application of the approach to HCR spur gears has produced two promising design cases, namely the short and long reliefs, with advantages and disadvantages. In this paper a new relief type, double relief, is introduced by making use of the two promising cases. Advantages of the two are brought together, with some compromise. The overall performance of the new relief type, however, is superior to the others in terms of peak-to-peak TE value, maximum tooth load value, rate of tooth loading and number of smooth TE curves, and hence in terms of the range of transmitted load with nearly uniform motion transfer. A procedure for compensation for adjacent pitch error (PE) with smooth TE curve at off-design load is also included.

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Mohammadi, Aidin, Alireza Pachenari, and Behnam Sadeghi. "Numerical Study on the Behavior and Bearing Mechanism of Flat Slabs in Column Loss Events." Advances in Civil Engineering 2021 (February 6, 2021): 1–12. http://dx.doi.org/10.1155/2021/8834638.

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This study investigates the behavior and the load-bearing mechanism of a typical flat slab with rectangular panels in several scenarios including the removal of a corner, penultimate, and internal columns. The scenarios are rather similar to those used in the conventional evaluation of the progressive collapse potential; however, application of the uniformly distributed loading over panels adjacent to the removed columns was not limited to twice the value of the initial load. Thus, load-deflection curves were drawn up to the point in which a great number of longitudinal slab bars ruptured. Introducing 5 stages on each curve, finite element outputs on concrete cracking pattern and rebar stress state were presented. A significant increase in the stresses along the diagonals of the slab panels accompanied by bar ruptures around columns adjacent to the removed column proved contribution of an important load-bearing mechanism in addition to the behavior called “quasiframe action.” Consecutive rupture of bars showed formation of a zipper-type collapse mode as well as a great tendency to transfer load share of missing column mainly along shorter direction of slab panels. Moreover, the findings indicated that the slab damaged zone could exceed the panels under uniform overloading.

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Dada, Thais Lucouvicz, and Faiçal Massad. "Interpretation of bi-directional tests on piles with the evaluation of stress relief at the pile toe." Soils and Rocks 44, no. 2 (June 18, 2021): 1–5. http://dx.doi.org/10.28927/sr.2021.062021.

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This paper presents the interpretation of bi-directional load tests performed on three auger piles, in the city of São Paulo, Brazil, using a method based on transfer functions for the shaft and toe. Elastic shortenings of the shaft were directly measured through a displacement indicator at the pile top and two telltales at the upper and bottom plates of the expansive cell. The equivalent top-down load-settlement curves were estimated and compared with two other methods from the literature, one which considers the pile infinitely rigid; and the other, which takes the pile elastic shortening into account. The curves resulted in good agreement considering the pile compressibility. Yet for the infinitely rigid pile, the settlements resulted in up to 75% smaller. Furthermore, the influence of stress relief on the toe behavior due to shaft lifting was investigated. For the cases studied, involving bored and auger piles with the slenderness ratio (Ls/r) greater than 20, the percentage of this effect was generally small, up to 5% of the toe load, being negligible for practical uses.

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Fellenius, Bengt H. "Discussion of “Development of Axial Pile Load Transfer Curves Based on Instrumented Load Tests” by Cécilia Bohn, Alexandre Lopes dos Santos, and Roger Frank." Journal of Geotechnical and Geoenvironmental Engineering 144, no. 4 (April 2018): 07018005. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001867.

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Bohn, Cécilia, Alexandre Lopes dos Santos, and Roger Frank. "Closure to “Development of Axial Pile Load Transfer Curves Based on Instrumented Load Tests” by Cécilia Bohn, Alexandre Lopes dos Santos, and Roger Frank." Journal of Geotechnical and Geoenvironmental Engineering 144, no. 4 (April 2018): 07018006. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001868.

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Naggar, M. Hesham El, and Kevin J. Bentley. "Dynamic analysis for laterally loaded piles and dynamic p-y curves." Canadian Geotechnical Journal 37, no. 6 (December 1, 2000): 1166–83. http://dx.doi.org/10.1139/t00-058.

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Pile foundations are often subjected to lateral dynamic loading due to forces on the supported structure. In this study, a simple two-dimensional analysis was developed to accurately model the pile response to dynamic loads. The proposed model incorporates the static p-y curve approach (where p is the static soil reaction and y is the pile deflection) and the plane strain assumptions to represent the soil reactions within the frame of a Winkler model. The p-y curves are used to relate pile deflections to the nonlinear soil reactions. Wave propagation and energy dissipation are also accounted for along with discontinuity conditions at the pile-soil interface. The inclusion of damping with the static unit transfer curves results in increased soil resistance, thus producing "dynamic p-y curves." The dynamic p-y curves are a function of the static p-y curve and velocity of the soil particles at a given depth and frequency of loading. The proposed model was used to analyze the pile response to the lateral Statnamic load test, and the predicted response compared well with the measured response. Closed-form solutions for dynamic p-y curves were established by curve fitting the dynamic soil reactions for a range of soil types and loading frequencies. These solutions can be used to model soil reactions for pile vibration problems in readily available finite element analysis (FEA) and dynamic structural analysis packages. A simple spring and dashpot model was also proposed to be used in equivalent linear analyses of transient pile response. The proposed models were incorporated into an FEA program (ANSYS) which was used to compute the response of a laterally loaded pile. The computed responses compared well with the predictions of the two-dimensional analysis.Key words: dynamic, transient, lateral, piles, p-y curves, inertial interaction.

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Liu, Kai An, and Qiu Ju Li. "Dynamics Simulation of Beam-Carried Cranes Based on Virtual Prototyping." Applied Mechanics and Materials 130-134 (October 2011): 1105–8. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.1105.

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Firstly this paper introduces the flexibility theory of virtual prototyping. Secondly a virtual prototype of rigid-flexible coupling model for beam-carried cranes is built, based on collaborative simulation platform by using the software of UG, ADAMS and ANSYS. Finally the response curves of the displacement for the girder’s centroid with step load and different frequency sine load were analyzed by virtual prototyping simulation. And the corresponding second-order system transfer function is given through the system identification. The result of simulation provided some theory basis for the structure design and optimization of beam-carried cranes.

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Behbehani, Fatemah, and John S. McCartney. "Impacts of Unsaturated Conditions on The Ultimate Axial Capacity of Energy Piles." E3S Web of Conferences 195 (2020): 04005. http://dx.doi.org/10.1051/e3sconf/202019504005.

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This study uses concepts from unsaturated soil mechanics to explain changes in axial capacity observed in geotechnical centrifuge experiments on semi-floating energy piles in unsaturated silt heated monotonically to different temperatures. Thermally-induced drying of the unsaturated silt surrounding energy piles was observed during heating using temperature-corrected dielectric sensor readings. An effective stress-based equation for estimating the ultimate capacity was calibrated using the load-settlement curves for a pile at room-temperature, which was then used to estimate the ultimate capacities of energy piles under elevated temperatures using measured changes in degree of saturation near the energy pile. The predicted capacity matched well with the capacity from the experimental load-settlement curves, confirming the relevance of the effective stress principle in unsaturated soils in nonisothermal conditions and the importance of considering coupled heat transfer and water flow in unsaturated soils surrounding energy piles.

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Bykov, K. V., N. M. Lazareva, and V. M. Yarov. "Dynamic Conditions for a Three-level LLC Converter with a Phase-Pulse Control." E3S Web of Conferences 124 (2019): 01013. http://dx.doi.org/10.1051/e3sconf/201912401013.

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Usually, parametric synthesis of controllers for a closed control system is carried out for nominal conditions, and then the source performance for other load resistance values is estimated. As a result, the control system may not always provide the sufficient mode stabilization with a changing load resistance value. The paper suggests an alternative version. It deals with estimation of dynamic transient responses for the required mode parameter in an open-circuit system as well as with determination of transfer functions and the controller parameters for the most complicated version of transient response curves. The paper presents the results of simulation modelling of dynamic operating conditions for LLC converter using Simulink Matlab as well as load characteristics for three versions of a closed control system.

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Wang, Xiu Li, and Qiong Li. "Seismic Performance on Dumbbell-Shape Connection between Steel Beams and Rectangular Concrete-Filled Tubular Column." Advanced Materials Research 163-167 (December 2010): 4546–54. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.4546.

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Referancing to the connection characteristic and mechanical behavior as well as the defects in application of joints on concrete-filled steel tube between columns and beams, a new connection type of steel beam throughout joints model is proposed. The inner force transfer mechanism and stress distribution situation of the joint under the monotonous load and hysteretic behavior, ductility, energy dissipation under cyclically lateral load are analyzed using the software ANSYS. The result indicated that the stress of steel pipe is reduced effectively when continious web plate joint is used. Meanwhile, the rigidity of the joint is enhancedand. It is also accord with the seismic design concepts, that is “strong column-weak beam“. During this process of the jiont working, plastic hinge occurs out of joint area on the beam. The hysteretic curves of all the specimens are of a plump shuttle shape .The curves don’t show strength deterioration and stiffness degradation obviously. All these show that this type of joint is effective.

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Wang, Jingang, Chen Shen, Pengcheng Zhao, Shucheng Ou, Zhi Xu, Ruiqiang Zhang, and Zhiming Song. "A Design Method for Magnetically Coupled Resonant Coils Considering Transmission Objectives and Dimension Constraints." Energies 13, no. 16 (August 11, 2020): 4144. http://dx.doi.org/10.3390/en13164144.

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This paper proposes a coil design method for the magnetically coupled resonant wireless power transfer (MCR-WPT) system. Based on the Biot–Savart law, the magnetic flux density at the observation point was derived, and the magnetic flux of the observation plane generated by the exciting coil was deduced to build the calculation model of power transfer efficiency (PTE) and power delivered to the load (PDL). The PTE and PDL curves via coil parameters could be fitted in minutes using numerical calculation. The coil was designed according to transmission objectives and dimension constraints. In addition, the calculated PTE and PDL were compared with those from finite element analysis to verify the credibility of the method. Finally, the actual curves of PTE and PDL were achieved, which showed a strong positive correlation with the corresponding curves from the calculation model. The relative average deviations of PDL curves were less than 6.11%. Meanwhile, coils designed with the numerical calculation could realize 309.80 W and 88.51%, which achieved the objectives under the constraints. The results demonstrate that the proposed method can realize a rapid and accurate coil design under constraints. It can also be applied to other coil structures or circuit topologies with strong universality.

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Horvath, Robert G., and K.-J. Chae. "Long-term settlement of model rock-socketed piers." Canadian Geotechnical Journal 26, no. 3 (August 1, 1989): 348–58. http://dx.doi.org/10.1139/t89-049.

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Very little information is available concerning the long-term settlement behaviour of drilled pier foundations socketed into rock. This paper summarizes the results of laboratory investigations of the long-term settlement (creep) behaviour of model socketed pier foundations. The testing program included seven model piers constructed with different materials and different load-support conditions. The primary models were two small-diameter concrete piers constructed in soft shale. For all models tested the results indicated similarly shaped time–displacement curves, having two distinct regions. The initial portion of the curves represents a region of primary creep and the remaining portion represents a zone of secondary creep having a much lower rate of displacement. A comparison of short-term (1 day, which is a normal maximum duration of a full-scale load test) and long-term (200 days) settlements for the model piers showed an 84–245% increase in settlements. In addition, some information concerning load transfer with time in the model piers and available data from loading tests on large-scale socketed piers are included. Key words: socketed pier foundations, long-term settlement, creep model tests, soft rock.

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Xu, Xiangyang, Xing Ai, Renxiang Chen, Guosong Jiang, and Xia Hua. "Research on roll stability of articulated engineering vehicles based on dynamic lateral transfer load." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 9 (April 20, 2020): 2364–76. http://dx.doi.org/10.1177/0954407020909242.

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A 16-degree-of-freedom non-linear roll dynamic model is developed for an articulated engineering vehicle considering non-linear road excitations and non-linear characteristics of vehicle structures. In addition, a variable step-size numerical method is proposed to solve the non-linear dynamic model. The proposed numerical method can improve the calculation accuracy and the computational stability. Through the proposed dynamic model, an equation is derived considering time-varying tire load characteristics to reflect the roll stability of an articulated engineering vehicle. Using the proposed roll stability equation, the driving stability can be effectively evaluated for an articulated engineering vehicle with different system parameters. The analysis results show that the roll stability decreases significantly with the increase in vehicle speed, centroid height of engineering vehicle, or lateral slope angle. The influence of vehicle speed and lateral slope angle on roll stability is greater than that of the centroid height of engineering vehicle. When steering on the road with a lateral slope angle, the roll angle and the lateral load transfer ratio curves fluctuate with time. As the lateral slope angle increases, the fluctuation is stronger. Overall, the proposed model can accurately evaluate the roll stability of a driving articulated engineering vehicle and accurately determine the unstable tilting of an articulated engineering vehicle.

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Yang, Qing Guang, Yi Han Chen, Jie Tian, and Jie Liu. "Model Test Research on Horizontal Bearing Characteristics of Close-Ended Valibale Section Pipe Pile." Applied Mechanics and Materials 638-640 (September 2014): 475–79. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.475.

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Base on indoor model tests of three variable section pipe piles and two constant section pipe piles performed in foundation pit,the load transfer mechanism of two kinds of close-ended pipe piles are studied by comparing horizontal load-displacement curves, critical load and bending moment of piles. Results show that horizontal load-displacement curves change slowly and horizontal bearing capacity of valiable section pipe piles will be higher than constant section pipe piles with equal average diameters.Comparing with constant section pipe piles 1# and 2# with equal average diameters, unit volume horizontal critical bearing capacity of 3# and 4# are improved 8.7% and 34.2% respectively and which have different degrees of increse with improvement of valiable section ratio. Moreover,there are two maximum bending moment to valialble section pipe piles insteard of one to constant section pipe piles.To pipe piles 3#,4# and 5#, maximum bending moment ratio of big diameter pipe to small diameter pipe of valiable section pipe pile are 3.13、2.33 and 1.89 respectively. To pipe piles 3# and 4#, maximum bending moments of big diameter pipe are improved 26.8% and 28.4%.Howeverm,maximum bending moment of small diameter pipe are improved 54.1% and 111.8%.So,it is very clear that valiable section pipe pile is more reasonable than constant section pipe pile in bearing characteristics.

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Lyu, Li-Hua, Wen-Di Liu, Jing Guo, Chun-yan Wei, Yu-ping Zhao, Yong-fang Qian, Xiao-Qing Xiong, Ying Wang, and Yao-Li Huang. "Compression properties of three-dimensional I-shaped woven composites with basalt fiber filament tows." Journal of Engineered Fibers and Fabrics 14 (January 2019): 155892501988468. http://dx.doi.org/10.1177/1558925019884683.

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In order to improve the defect of incompleteness, three-dimensional I-shaped fabrics with basalt fiber filaments tows were woven on the semi-automatic loom by reasonable design. Three-dimensional I-shaped woven composites were prepared by the vacuum-assisted resin transfer molding process. The compressive behaviors of three-dimensional I-shaped woven composites with three different heights and thicknesses were studied. Through the evaluation of load–displacement curves and total energy absorption of the three-dimensional I-shaped woven composites, the results indicated when the thickness was fixed to 2 mm, the maximum compression load with height 20 mm raised 522.72 N as against that with height 60 mm and the maximum compression load with thickness 6 mm raised 2571.81 N as against that with thickness 2 mm. Consequently, the compression properties of three-dimensional I-shaped woven composites decreased with the increasing heights of the composites, while increased with the increasing thickness of the composites. Analyzing morphological characteristics of composites after fracture and load–displacement curves of composites, it was concluded that the compression failure modes had brittle fracture of the fiber bundle, cracking of the matrix, and a typical shear failure in the beam (A2). Despite the above-mentioned failure mechanisms, the three-dimensional I-shaped woven composite still had good integrity without delamination.

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Seefeldt, Marc, Steven Dillien, and Uwe Stuhr. "Neutron Diffraction Analysis of Load Transfer in DP 600 Steel During In Situ Tensile Tests." Materials Science Forum 681 (March 2011): 31–36. http://dx.doi.org/10.4028/www.scientific.net/msf.681.31.

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The load transfer among ferrite orientations and between ferrite and martensite was analysed in DP 600 steel by means of neutron diffraction duringin situtensile tests on the multiple pulse overlap time-of-flight strain scanner POLDI. The material had 0.07 wt% C and a martensite volume fraction of 15%.In situtests were done in “Young” as well as in “Poisson setup”. The martensite phase could not be probed due to its low tetragonality. The curves of the lattice plane strains as a function of the externally applied macroscopic stress reveal (1) plastic relaxations of transformation and intergranular stresses in the compliant <100> oriented grains, and (2) a second inflection point in the fully plastic part indicating the onset of plastic deformation of the hard phase.

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Du, Yong, Yu'e Ma, and Junwu Liu. "Fracture damage of integrated composite joint for fuselage structure under tensile loading." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 39, no. 4 (August 2021): 739–46. http://dx.doi.org/10.1051/jnwpu/20213940739.

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In order to solve the complex load transfer and structural design of the joint structures including skin, longeron and frame in the composite fuselage, the adhesively bonded integrated composite joint was designed. Static tensile test was performed and the strain-load curves and damage modes were obtained. Then the numerical simulation model of integrated composite joint was built. The damage initiation, propagation and failure process of integrated composite joint under tensile load were simulated and analyzed. Results show that: the first load drop and the ultimate failure load of the joint are 120.82 kN and 168.11 kN respectively; the initial damage occurs at the corner bend region of the lower-left corner-shaped preform, and extends across the radius bend region among short flange, long flange and web, and leads to the interface debonding of the upper and lower corner-shaped preform and the delamination of corner-shaped preform and L-shaped preform. Compared with the experimental results, the errors of the first load drop and the ultimate failure load from numerical calculated results are 6.68% and 2.61% respectively, which agree with each other very well.

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Zhao, Xia, Jianfeng Li, Ying Chen, Chunjing Tao, and Run Ji. "Investigation of load transfer process between external fixator and bone model by experimental and finite element methods." Journal of Applied Biomaterials & Functional Materials 17, no. 1 (January 2019): 228080001982651. http://dx.doi.org/10.1177/2280800019826512.

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Introduction: Unilateral external fixators are widely used in orthopedics to stabilize fractured bones and to treat limb deformities. One of the main problems is that it is difficult to detect healing status. In addition, whether load transfer progress between the fixator and bone model are the same under axial, torsional, and bending loads has not been studied. Methods: Therefore the main purpose of this study was to detect the load transfer process between the fixator and a bone model by measuring strains on the fixator–bone system during four healing states using experimental and finite element methods. In the experimental method, 20 strain gauges were used to measure strain on the fixator and bone model under three load conditions. Polyacetal slice models with different material properties were used to simulate the callus model during four growth states. Results: The results indicate that strain on the bone model increased and strain on the fixator parts decreased with maturation of the callus under axial, bending, and torsional loads. Although all curves showed a similar changing trend, they were slightly different under the three loads. Discussion and conclusions: This study provides a useful method to monitor the fracture healing process, and identifies the healing endpoint, detects healing status, and provides useful information for the orthopedist.

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Dai, Guoliang, Rodrigo Salgado, Weiming Gong, and Yanbei Zhang. "Load tests on full-scale bored pile groups." Canadian Geotechnical Journal 49, no. 11 (November 2012): 1293–308. http://dx.doi.org/10.1139/t2012-087.

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The interactions between closely spaced piles in a pile group are complex. Very limited experimental data are available on the loading of full-scale bored pile groups. This paper reports the results of axial static load tests of both full-scale instrumented pile groups and single piles. The load tests aimed to ascertain the influence of number, length, and spacing of the piles on pile group load response. Experiments varied in the number of piles in the group, pile spacing, type of pile groups, and pile length. All piles had a diameter of 400 mm. Two-, four-, and nine-pile groups with pile lengths of 20 and 24 m were tested. As the isolated piles and some piles in the pile groups were instrumented, the load transfer and load–settlement curves of both piles in isolation and individual instrumented piles in the groups were obtained. The interaction coefficient for each pile in the group was back-calculated from the measured data. The interaction coefficients are shown to be dependent on pile proximity, as usually assumed in elastic analyses, but also on settlement and on the size of the group.

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Zhang, Xiao Xia, and Yu Qiang Ma. "The Dynamics Studies of a Four-Axle Bogie of Locomotive." Advanced Materials Research 753-755 (August 2013): 1745–50. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.1745.

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A type of bogie structure was proposed for the eight-axle locomotive, of which the middel bogie forme was used to connect the two B0 bogie and support the car body with three suspensions. A single drawbar connect the B0 bogie and car body directly to transfer the longitudinal forces. This structure is simple and feasibility, which can achieve high adhesion availabillity and good dynamic performances. Three suspension can achieve a excellent stability of car body. Comparing with a same speed and axle load class 2C0 locomotive, the wheelset lateral force and wheel rim wear factor are reduced by about 35% at the R300m small radius curves, and the wheelset lateral force is decreased by 15%, and the rim wear factor is reduced by 23% at the R800m curves.

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Doghman, Mirna, Hussein Mroueh, and Sébastien Burlon. "Piles in chalk under axial loading." MATEC Web of Conferences 281 (2019): 01002. http://dx.doi.org/10.1051/matecconf/201928101002.

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Chalk exhibits a viscous behavior depending on time and it presents a noticeable creep under constant load. Consequently, piles founded in chalk media may have their design greatly affected. However, the different standards of the design of deep foundations don’t take into account this viscous behavior and its effect on the pile settlement in the long term. This paper deals with the case of piles under monotonic axial loads in chalk. Two methods of predicting pile settlement are developed: the transfer curves method tz, taking into account the viscosity, and the macroelement technique.

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Ezeruigbo, E. N., A. O. Ekwue, and L. U. Anih. "Voltage Stability Analysis of Nigerian 330kV Power Grid using Static P-V Plots." Nigerian Journal of Technology 40, no. 1 (March 23, 2021): 70–80. http://dx.doi.org/10.4314/njt.v40i1.11.

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Nigeria power system has been experiencing total or partial system failures in recent times and voltage instability is a strong factor. The paper seeks to perform the voltage stability analysis, based on static P-V plots, on buses located around and within the South East zone of Nigeria. An injection group containing generators to serve as the source and a sink group as loads to be monitored are created. The generators are assumed to be within their min/max MW limits. The load is increased in the sink group as well as in the source group to maintain the same generation/load balance. Load power and bus voltages (P-V) curves are plotted on the load busbars and the first busbar to reach the voltage collapse and MW transfer limit are determined. From the results obtained, at a load of 100 MW, Makurdi bus recorded a voltage of 0.9301 pu which is already below the regulatory standards of ±5% of the nominal line voltage. It entered the region of instability at a load of 245 MW. This created a situation of system instability and a possible partial system collapse. Subsequently, at a load of 260 MW, the system clearly entered unstable region giving rise to partial system collapse of the network.

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Ding, Dayi, Meng Wang, Yuanqing Wang, Bin Pan, and Yongjiu Shi. "Experimental and analytical investigations on a large floor truss pinned connection." Advances in Structural Engineering 20, no. 7 (October 7, 2016): 1007–23. http://dx.doi.org/10.1177/1369433216670169.

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The pinned connection method was used to connect the large-span floor truss to the steel column in Zoucheng International Conference Center project, which played a quite important role to achieve the in-plane rotation and transfer heavy loads directly. Four specimens were tested experimentally to investigate the monotonic and cyclic behavior of this connection method, including two independent pinned connections and two assembled truss connections. The load–displacement curves, deformation development, failure mode, ductility, and energy dissipation capacity were discussed in detail. Besides, the nonlinear multi-scale finite element models of the pinned and truss connections were established. The numerical simulations not only captured the global behavior and local limit states observed in tests but also revealed valuable new information that could not be directly obtained from the tests. The experimental and numerical results showed that both the pinned and truss connections had good ductility, load transfer ability, and ideal rotation capacity with large safety margin, indicating these constructions could be used as references for similar projects.

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Lv, Lihua, Yaoli Huang, Jingrui Cui, Yongfang Qian, Fang Ye, and Yuping Zhao. "Bending properties of three-dimensional honeycomb sandwich structure composites: experiment and Finite Element Method simulation." Textile Research Journal 88, no. 17 (April 7, 2017): 2024–31. http://dx.doi.org/10.1177/0040517517703602.

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This paper fabricated three-dimensional (3D) honeycomb sandwich structure fabrics with three different cross-section shapes on an ordinary loom by reasonable design with low cost. The 3D honeycomb sandwich structure composites were fabricated by the vacuum assisted resin transfer molding process. Then, the bending properties of 3D honeycomb sandwich structure composites with different cross-section shapes were tested. The results showed that the 3D honeycomb sandwich structure composite with a hexagonal cross-section shape had the maximum load, the 3D honeycomb sandwich structure composite with a triquetrous cross-section shape had the minimum load and the 3D honeycomb sandwich structure composite with a quadrangular cross-section shape had a load between the two. The bending failure mode showed that the 3D honeycomb sandwich structure composite had a typical bending failure mode with compression failure in the front and tensile failure in the back. Finally, the load–displacement curves and failure mode were obtained by FEM (Finite Element Method) simulation with ABAQUS software. The good agreements of comparisons proved the validity of the FEM.

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Trinh, Chuong Trong. "VOLTAGE STABILITY INVESTIGATION OF GRID CONNECTED WIND FARM." Science and Technology Development Journal 12, no. 8 (April 28, 2009): 38–46. http://dx.doi.org/10.32508/stdj.v12i8.2273.

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At present, it is very common to find renewable energy resources, especially wind power, connected to distribution systems. The impact of this wind power on voltage distribution levels has been addressed in the literature. The majority of this works deals with the determination of the maximum active and reactive power that is possible to be connected on a system load bus, until the voltage at that bus reaches the voltage collapse point. It is done by the traditional methods of P-V curves reported in many references. Theoretical expression of maximum power limited by voltage stability transfer through a grid is formulated using an exact representation of distribution line with ABCD parameters. The expression is used to plot PV curves at various power factors of a radial system. Limited values of reactive power can be obtained. This paper presents a method to study the relationship between the active power and voltage (PV) at the load bus to identify the voltage stability limit. It is a foundation to build a permitted working operation region in complying with the voltage stability limit at the point of common coupling (PCC) connected wind farm.

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Journal articles on the topic 'Load-transfer curves'

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