Studies on the Stress-Strain Relationship Bovine Cortical Bone Based on Ramberg–Osgood Equation

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
N. K. Sharma ◽  
M. D. Sarker ◽  
Saman Naghieh ◽  
Daniel X. B. Chen
Keyword(s):  
Cortical Bone ◽  
Linear Regression Analysis ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Loading Conditions ◽  
Stress Strain ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Strain Relationship ◽  
Relationship Of

Bone is a complex material that exhibits an amount of plasticity before bone fracture takes place, where the nonlinear relationship between stress and strain is of importance to understand the mechanism behind the fracture. This brief presents our study on the examination of the stress–strain relationship of bovine femoral cortical bone and the relationship representation by employing the Ramberg–Osgood (R–O) equation. Samples were taken and prepared from different locations (upper, middle, and lower) of bone diaphysis and were then subjected to the uniaxial tensile tests under longitudinal and transverse loading conditions, respectively. The stress–strain curves obtained from tests were analyzed via linear regression analysis based on the R–O equation. Our results illustrated that the R–O equation is appropriate to describe the nonlinear stress–strain behavior of cortical bone, while the values of equation parameters vary with the sample locations (upper, middle, and lower) and loading conditions (longitudinal and transverse).

Inelastic Strain Accumulation in Cortical Bone During Rapid Transient Tensile Loading

1999 ◽  
Vol 121 (6) ◽  
pp. 616-621 ◽  
Author(s):  
M. T. Fondrk ◽  
E. H. Bahniuk ◽  
D. T. Davy
Keyword(s):  
Cortical Bone ◽  
Axial Strain ◽  
Human Bone ◽  
Elastic Behavior ◽  
Transverse Strain ◽  
Bovine Bone ◽  
Stress Strain ◽  
Nonlinear Strain ◽  
Strain Behavior ◽  
Nonlinear Stress

An experimental study examined the tensile stress-strain behavior of cortical bone during rapid load cycles to high strain amplitudes. Machined bovine and human cortical bone samples were subjected to loading cycles at a nominal load/unload rate of ±420 MPa/s. Loads were reversed at pre-selected strain levels such that load cycles were typically completed in 0.5-0.7 seconds. Axial strain behavior demonstrated considerable nonlinearity in the first load cycle, while transverse strain behavior was essentially linear. For the human bone 29.1 percent (S.D. = 4.7 percent), and for the bovine bone 35.1 percent (S.D. = 10.8 percent) of the maximum nonlinear strain accumulated after load reversal, where nonlinear strain was defined as the difference between total strain and strain corresponding to linear elastic behavior. Average residual axial strain on unloading was 35.4 percent (S.D. = 1.2 percent) for human bone and 35.1 percent (S.D. = 2.9 percent) of maximum nonlinear strain. Corresponding significant volumetric strains and residual volumetric strains were found. The results support the conclusions that the nonlinear stress-strain behavior observed during creep loading also occurs during transient loading at physiological rates. The volume increases suggest that damage accumulation, i.e., new internal surfaces and voids, plays a major role in this behavior. The residual volume increases and associated disruptions in the internal structure of bone provide a potential stimulus for a biological repair response.

Analysis of the Mechanic Behavior and Rutting of Asphalt Concrete Using a Sand Model

1999 ◽  
Vol 15 (4) ◽  
pp. 177-184
Author(s):  
Ming-Lou Liu
Keyword(s):  
Asphalt Concrete ◽  
Stress Path ◽  
Plasticity Model ◽  
Test Results ◽  
Research Subjects ◽  
Stress Strain ◽  
Strain Behavior ◽  
Strain Relationship ◽  
Concrete Materials ◽  
Relationship Of

AbstractThe stress-strain relationship of the sand and asphalt concrete materials is one of the most important research subjects in the past, and many conctitutive laws for these materials have been proposed in the last two decades. In this study, the Vermeer plasticity model is modified and used to predict the behavior of the sand and asphalt concrete materials under different stress path conditions. The results show that the predictions and test results agree well under different stress path conditions. However, the orignal Vermeer model can not predict the stress-strain behavior of the asphalt concrete. Finally, the modified Vermeer plasticity model is incorporated with the pavement rutting model to predict the rut depth of pavement structure under traffic loadings.

Establishment of Stress-Strain Relationships of Tailor-Welded Tubes via DIC Method Based on Uniaxial Tensile Tests

2014 ◽  
Vol 611-612 ◽  
pp. 475-482 ◽  
Author(s):  
Hui Ji Jia ◽  
Lian Fa Yang ◽  
Jian Wei Liu
Keyword(s):  
Image Correlation ◽  
Uniaxial Tensile ◽  
Displacement Curve ◽  
Stress Strain ◽  
Material Parameters ◽  
Rule Of Mixtures ◽  
Strain Relationship ◽  
Load Displacement ◽  
Relationship Of ◽  
Strain Method

Tailor-welded tubes are widespread in aircraft and automotive industries due to their advantages of low cost, reduction in part weight and flexibility in mass production. It is necessary to obtain the stress-strain relationship of tailor-welded tubes to study deformation behaviors of tubes and simulate deformation tests of tubes. Then a method via digital image correlation (DIC) method based on uniaxial tensile test (UTT) is proposed in this paper to establish stress-strain relationship of tailor-welded tubes. Material parameters of tailor-welded tubes obtained from three methods, i.e. the method based on UTT, the iso-strain method based on a rule of mixtures and the proposed method, were compared in this paper. To assess the accuracy of material parameters obtained from these three methods, UTTs were simulated, and load-displacement curves and maximal loads obtained from simulations were compared with those obtained from UTTs. In simulations of UTTs, finite element models of specimens of sole parent metal and mixed specimens were established, respectively. The results show that: When HAZ included in the specimen has large proportion of the specimen, the proposed method is more reliable than the iso-strain method based on a rule of mixtures on determining the material parameters of the weld; load-displacement curve and maximal load obtained from the proposed method are more close to those obtained from UTT than those obtained from the method based on UTT.

A Statistical Constitutive Model for the Strength of Brittle Fiber at Different Strain Rates

2010 ◽  
Vol 152-153 ◽  
pp. 1213-1216
Author(s):  
Wen Huang ◽  
Zhong Wei Huang
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Tensile Tests ◽  
Fiber Bundles ◽  
Strain Rates ◽  
Stress Strain ◽  
Sic Fiber ◽  
Brittle Fiber ◽  
Strain Relationship ◽  
Relationship Of

A statistical constitutive model, which takes account the effect of strain rate, was presented to describe the stress-strain relationship of brittle fiber bundles. To verify its reliability, tensile tests on two kinds of brittle fibers: glass fiber and SiC fiber, were carried out at different strain rates, and the stress-strain curves were obtained. It was found that the modulus E, the strength and the fracture strain of these fiber bundles all increase with increasing strain rate. The simulated stress-strain curves, derived from the constitutive model, fit the tested results well, which indicates that the model is valid and reliable.

Normalized Stress-Strain Behavior of Yingkou Clay

2013 ◽  
Vol 838-841 ◽  
pp. 47-52
Author(s):  
Fu Yi ◽  
Hong Yu Wang
Keyword(s):  
Strain Hardening ◽  
Principal Stress ◽  
Soft Soil ◽  
Confining Pressure ◽  
Stress Strain ◽  
Strain Behavior ◽  
Strain Relationship ◽  
Relationship Of ◽  
Is Strain

In order to systemic study the normalized stress-strain relationship behavior of Yingkou clay. By the consolidated undrained triaxial sherar test of Yingkou clay, obtaining that stress-strain relationship is strain hardening under different confining pressures.A kind of cementation structure in the soil directly affects soft soil strength.And the paper contrast four kinds of normalized factors to study stress-strain characteristics,which are confining pressurethe average consolidation pressureand the ultimate value of principal stress.The results indicate that the normalized degree is more accurate when used value of principal stress and as normalized factor. Meanwhile the normalized stress-strain relationship of Yingkou clay under consolidated undrained condition is established,which can well predict the stress-strain relationship under different confining pressure.

scholarly journals Experimentation of the Bilinear Elastic Behavior of Plain-Woven GFRP Composite with Embedded SMA Wires

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 405 ◽  
Author(s):  
Zhiwei Sun ◽  
Yingjie Xu ◽  
Wenzhi Wang
Keyword(s):  
Tensile Strain ◽  
Tensile Tests ◽  
Elastic Behavior ◽  
Uniaxial Tensile ◽  
Stress Strain ◽  
Strain Behavior ◽  
Reinforced Polymer ◽  
Resin Injection ◽  
Stress Threshold ◽  
Gfrp Composite

In this paper, a plain-woven glass-fabric-reinforced polymer (GFRP) composite with embedded shape memory alloy (SMA) wires is investigated by means of experiments. The vacuum-assisted resin injection (VARI) method is utilized to fabricate the composite specimens. Quasi-static uniaxial tensile tests are then carried out to evaluate the influence of SMA reinforcement on the stress–strain behavior of the composite. Only the elastic behavior of the composite is considered in the present study. The tensile strain in all the experiments is kept below 2.5% to avoid debonding of the SMA-resin interface, which would lead to failure of the composite. Stress–strain curves are obtained and shown to present a bilinear behavior due to phase transformation taking place in the SMA wires beyond a certain stress threshold.

scholarly journals Stress-Strain Relationship of Ca(OH)2-Activated Hwangtoh Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Keun-Hyeok Yang ◽  
Ju-Hyun Mun ◽  
Hey-Zoo Hwang
Keyword(s):  
Compressive Strength ◽  
Strain Curve ◽  
Peak Stress ◽  
Actual Behavior ◽  
Test Results ◽  
Stress Strain ◽  
Strain Behavior ◽  
Strain Relationship ◽  
Relationship Of ◽  
Strain Model

This study examined the stress-strain behavior of 10 calcium hydroxide (Ca(OH)2)-activated Hwangtoh concrete mixes. The volumetric ratio of the coarse aggregate (Vagg) and the water-to-binder (W/B) ratio were selected as the main test variables. TwoW/Bratios (25% and 40%) were used and the value ofVaggvaried between 0% and 40.0%, and 0% and 46.5% forW/Bratios of 25% and 40%, respectively. The test results demonstrated that the slope of the ascending branch of the stress-strain curve of Ca(OH)2-activated Hwangtoh concrete was smaller, and it displayed a steeper drop in stress in the descending branch, compared with those of ordinary Portland cement (OPC) concrete with the same compressive strength. This trend was more pronounced with the increase in theW/Bratio and decrease inVagg. Based on the experimental observations, a simple and rational stress-strain model was established mathematically. Furthermore, the modulus of elasticity and strain at peak stress of the Ca(OH)2-activated Hwangtoh concrete were formulated as a function of its compressive strength andVagg. The proposed stress-strain model predicted the actual behavior accurately, whereas the previous models formulated using OPC concrete data were limited in their applicability to Ca(OH)2-activated Hwangtoh concrete.

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