A Cellular Solid Criterion for Predicting the Axial-Shear Failure Properties of Bovine Trabecular Bone

1999 ◽  
Vol 121 (4) ◽  
pp. 414-422 ◽  
Author(s):  
C. M. Fenech ◽  
T. M. Keaveny
Keyword(s):  
Trabecular Bone ◽  
Shear Failure ◽  
Shear Loading ◽  
Principal Strain ◽  
Failure Behavior ◽  
Linear Superposition ◽  
Cellular Solid ◽  
Axial Shear ◽  
Failure Properties ◽  
Von Mises

In a long-term effort to develop a complete multi-axial failure criterion for human trabecular bone, the overall goal of this study was to compare the ability of a simple cellular solid mechanistic criterion versus the Tsai–Wu, Principal Strain, and von Mises phenomenological criteria—all normalized to minimize effects of interspecimen heterogeneity of strength—to predict the on-axis axial-shear failure properties of bovine trabecular bone. The Cellular Solid criterion that was developed here assumed that vertical trabeculae failed due to a linear superposition of axial compression/tension and bending stresses, induced by the apparent level axial and shear loading, respectively. Twenty-seven bovine tibial trabecular bone specimens were destructively tested on-axis without end artifacts, loaded either in combined tension-torsion (n = 10), compression-torsion (n = 11), or uniaxially (n = 6). For compression-shear, the mean (± S.D.) percentage errors between measured values and criterion predictions were 7.7 ± 12.6 percent, 19.7 ± 23.2 percent, 22.8 ± 18.9 percent, and 82.4 ± 64.5 percent for the Cellular Solid, Tsai–Wu, Principal Strain, and von Mises criteria, respectively; corresponding mean errors for tension-shear were –5.2 ± 11.8 percent, 14.3 ± 12.5 percent, 6.9 ± 7.6 percent, and 57.7 ± 46.3 percent. Statistical analysis indicated that the Cellular Solid criterion was the best performer for compression-shear, and performed as well as the Principal Strain criterion for tension-shear. These data should substantially improve the ability to predict axial-shear failure of dense trabecular bone. More importantly, the results firmly establish the importance of cellular solid analysis for understanding and predicting the multiaxial failure behavior of trabecular bone.

Axial-Shear Failure Behavior of Human Femoral Trabecular Bone

1999 ◽  
Author(s):  
Yves P. Arramon ◽  
Oscar C. Yeh ◽  
Elise F. Morgan ◽  
Tony M. Keaveny
Keyword(s):  
Mechanical Behavior ◽  
Trabecular Bone ◽  
Failure Criterion ◽  
Shear Failure ◽  
Computer Models ◽  
Failure Behavior ◽  
Multiaxial Loading ◽  
Bone Implant ◽  
Computer Aided ◽  
Stress States

Abstract An understanding of the failure of trabecular bone subjected to multiaxial loading has relevance in the mechanics of trauma and bone implant interfaces. The development of computer aided tomography-based computer models allow predictions of the mechanical behavior of whole bones when subjected to stress states too complex to be described analytically (Ford et al., 1996; Keyak et al., 1998; Oden et al., 1998). However, these models cannot confidently predict the failure of the trabecular bone without an experimentally validated multiaxial failure criterion.

scholarly journals Compression Shear Properties of Bonded–Bolted Hybrid Single-Lap Joints of C/C Composites at High Temperature

2020 ◽  
Vol 10 (3) ◽  
pp. 1054
Author(s):  
Yanfeng Zhang ◽  
Zhengong Zhou ◽  
Zhiyong Tan
Keyword(s):  
High Temperature ◽  
Failure Modes ◽  
Shear Failure ◽  
Shear Loading ◽  
Lap Joints ◽  
Failure Behavior ◽  
Displacement Curve ◽  
Analysis Model ◽  
Single Lap Joints ◽  
Hybrid Joints

Based on previous research, in this paper, the compressive shear failure behavior and mechanical properties of bonded–bolted hybrid single-lap joints of C/C composites at high temperature were studied. The compression shear test was performed on the joints at 800 °C to obtain the load–displacement curve and failure morphology. The failure modes of joints were observed by digital microscopy and scanning electron microscopy. A numerical analysis model was implemented in finite element code Abaqus/Explicit embedded with the user material subroutine (VUMAT). The numerical results were compared with the test results to verify the correctness of the model. The interrelationship of the compression shear loading mechanism and the variations in stress distribution between bonded joints and bonded–bolted hybrid joints at high temperature were explored. The progressive damage of hybrid joints and the variations in the ratio of the bolt load to the total load with displacement were obtained.

scholarly journals An Experimental Study on Mechanical Behavior of Parallel Joint Specimens under Compression Shear

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Fei Wang ◽  
Ping Cao ◽  
Yu Chen ◽  
Qing-peng Gao ◽  
Zhu Wang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Failure Mode ◽  
Shear Failure ◽  
Strain Curve ◽  
Shear Loading ◽  
Plane Shear ◽  
Joint Spacing ◽  
Dip Angle ◽  
Joint Inclination

In order to investigate the influence of the joint on the failure mode, peak shear strength, and shear stress-strain curve of rock mass, the compression shear test loading on the parallel jointed specimens was carried out, and the acoustic emission system was used to monitor the loading process. The joint spacing and joint overlap were varied to alter the relative positions of parallel joints in geometry. Under compression-shear loading, the failure mode of the joint specimen can be classified into four types: coplanar shear failure, shear failure along the joint plane, shear failure along the shear stress plane, and similar integrity shear failure. The joint dip angle has a decisive effect on the failure mode of the specimen. The joint overlap affects the crack development of the specimen but does not change the failure mode of the specimen. The joint spacing can change the failure mode of the specimen. The shear strength of the specimen firstly increases and then decreases with the increase of the dip angle and reaches the maximum at 45°. The shear strength decreases with the increase of the joint overlap and increases with the increase of the joint spacing. The shear stress-displacement curves of different joint inclination samples have differences which mainly reflect in the postrupture stage. From monitoring results of the AE system, the variation regular of the AE count corresponds to the failure mode, and the peak value of the AE count decreases with the increase of joint overlap and increases with the increase of joint spacing.

scholarly journals Numerical analysis of the compressive and shear failure behavior of rock containing multi-intermittent joints

2019 ◽  
Vol 347 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Xiang Fan ◽  
Hang Lin ◽  
Hongpeng Lai ◽  
Rihong Cao ◽  
Jie Liu
Keyword(s):  
Numerical Analysis ◽  
Shear Failure ◽  
Failure Behavior

scholarly journals Deformation and Failure Behavior of Wooden Sandwich Composites with Taiji Honeycomb Core under a Three-Point Bending Test

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2325 ◽  
Author(s):  
Jingxin Hao ◽  
Xinfeng Wu ◽  
Gloria Oporto ◽  
Jingxin Wang ◽  
Gregory Dahle ◽  
...  
Keyword(s):  
Shear Failure ◽  
Dominant Role ◽  
Honeycomb Structure ◽  
Structure Design ◽  
Bending Test ◽  
Failure Behavior ◽  
Sandwich Composites ◽  
Honeycomb Core ◽  
Deformation And Failure ◽  
Three Point Bending

A new type of Taiji honeycomb structure bonded outside with wood-based laminates was characterized from a mechanical standpoint. Both theoretical and experimental methods were employed to analyze comprehensively the deformation behavior and failure mechanism under a three-point bending test. The analytical analysis reveals that a Taiji honeycomb has 3.5 times higher strength in compression and 3.44 times higher strength in shear compared with a traditional hexagonal honeycomb. Considering the strength-weight issue, the novel structure also displays an increase in compression strength of 1.75 times and shear strength of 1.72 times. Under a three-point bending test, indentation and core shear failure played the dominant role for the total failure of a wooden sandwich with Taiji honeycomb core. Typical face yield was not observed due to limited thickness-span ratio of specimens. Large spans weaken the loading level due to the contribution of global bending stress in the compressive skin to indentation failure. A set of analytical equations between mechanical properties and key structure parameters were developed to accurately predict the threshold stresses corresponding to the onset of those deformation events, which offer critical new knowledge for the rational structure design of wooden sandwich composites.

scholarly journals Failure behavior of woven fiberglass composites under combined compressive and environmental loading

2019 ◽  
Vol 54 (4) ◽  
pp. 519-533
Author(s):  
Ariana Paradiso ◽  
Isabella Mendoza ◽  
Amanda Bellafato ◽  
Leslie Lamberson
Keyword(s):  
High Speed ◽  
Shear Failure ◽  
Resin Composite ◽  
Compressive Loading ◽  
Image Correlation ◽  
Failure Behavior ◽  
High Speed Photography ◽  
Environmental Loading ◽  
Full Field ◽  
Environmental Conditioning

The purpose of this study is to quantitatively characterize the compressive and damage behavior of a woven fiberglass composite under combined environmental loading. Cuboidal samples of a commercially available woven fiberglass epoxy resin composite, garolite G10, are examined under uniaxial compressive loading perpendicular to the plies at quasi-static (10−3 s−1) and dynamic (103 s−1) strain rates using a standard load frame and Kolsky (split-Hopkinson) bar. In order to simulate environmental conditions, a subset of samples were soaked in either distilled or ASTM standard seawater prior to loading. Two time periods of environmental conditioning were investigated: short term at two weeks and long term at four months. Results demonstrate that, on average, the dynamic compressive strength of the fiberglass increased 35% from the quasi-static. Moreover, environmentally treated samples generally experienced a decrease strain to failure, and composites exposed to water for only short periods exhibited signs of the absorbed water sustaining additional load under quasi-static rates. Ultra-high-speed photography combined with digital image correlation, a full-field surface kinematic measurement technique, is used to map 2D strains on the sample during loading. In all cases, a clear shear failure mechanism from local instabilities appears, and a Mohr–Coulomb failure criterion is used to extract a mesoscale cohesive shear stress and coefficient of internal friction.

High-Resolution Three-Dimensional-pQCT Images Can Be an Adequate Basis for In-Vivo μFE Analysis of Bone

2000 ◽  
Vol 123 (2) ◽  
pp. 176-183 ◽  
Author(s):  
W. Pistoia ◽  
B. van Rietbergen ◽  
A. Laib ◽  
P. Ru¨egsegger
Keyword(s):  
High Resolution ◽  
Trabecular Bone ◽  
Elastic Properties ◽  
Bone Structure ◽  
Reference Model ◽  
Von Mises Stress ◽  
Micro Ct ◽  
Von Mises

Micro-finite element (μFE) models based on high-resolution images have enabled the calculation of elastic properties of trabecular bone in vitro. Recently, techniques have been developed to image trabecular bone structure in vivo, albeit at a lesser resolution. The present work studies the usefulness of such in-vivo images for μFE analyses, by comparing their μFE results to those of models based on high-resolution micro-CT (μCT) images. Fifteen specimens obtained from human femoral heads were imaged first with a 3D-pQCT scanner at 165 μm resolution and a second time with a μCT scanner at 56 μm resolution. A third set of images with a resolution of 165 μm was created by downscaling the μCT measurements. The μFE models were created directly from these images. Orthotropic elastic properties and the average tissue von Mises stress of the specimens were calculated from six FE-analyses per specimen. The results of the 165 μm models were compared to those of the 56 μm model, which was taken as the reference model. The results calculated from the pQCT-based models, correlated excellent with those calculated from the reference model for both moduli R2>0.95 and for the average tissue von Mises stress R2>0.83. Results calculated from the downscaled micro-CT models correlated even better with those of the reference models (R2>0.99 for the moduli and R2>0.96 for the average von Mises stress). In the case of the 3D-pQCT based models, however, the slopes of the regression lines were less than one and had to be corrected. The prediction of the Poisson’s ratios was less accurate (R2>0.45 and R2>0.67) for the models based on 3D-pQCT and downscaled μCT images respectively). The fact that the results from the downscaled and original μCT images were nearly identical indicates that the need for a correction in the case of the 3D-pQCT measurements was not due to the voxel size of the images but due to a higher noise level and a lower contrast in these images, in combination with the application of a filtering procedure at 165 micron images. In summary: the results of μFE models based on in-vivo images of the 3D-pQCT can closely resemble those obtained from μFE models based on higher resolution μCT system.

scholarly journals The Quartic Piecewise-Linear Criterion for the Multiaxial Yield Behavior of Human Trabecular Bone

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Arnav Sanyal ◽  
Joanna Scheffelin ◽  
Tony M. Keaveny
Keyword(s):  
Finite Element ◽  
Trabecular Bone ◽  
Volume Fraction ◽  
Yield Criterion ◽  
Shear Loading ◽  
Bone Volume ◽  
Mechanical Anisotropy ◽  
Bone Volume Fraction ◽  
Human Trabecular Bone ◽  
Strain Space

Prior multiaxial strength studies on trabecular bone have either not addressed large variations in bone volume fraction and microarchitecture, or have not addressed the full range of multiaxial stress states. Addressing these limitations, we utilized micro-computed tomography (μCT) based nonlinear finite element analysis to investigate the complete 3D multiaxial failure behavior of ten specimens (5 mm cube) of human trabecular bone, taken from three anatomic sites and spanning a wide range of bone volume fraction (0.09–0.36), mechanical anisotropy (range of E3/E1 = 3.0–12.0), and microarchitecture. We found that most of the observed variation in multiaxial strength behavior could be accounted for by normalizing the multiaxial strength by specimen-specific values of uniaxial strength (tension, compression in the longitudinal and transverse directions). Scatter between specimens was reduced further when the normalized multiaxial strength was described in strain space. The resulting multiaxial failure envelope in this normalized-strain space had a rectangular boxlike shape for normal–normal loading and either a rhomboidal boxlike shape or a triangular shape for normal-shear loading, depending on the loading direction. The finite element data were well described by a single quartic yield criterion in the 6D normalized-strain space combined with a piecewise linear yield criterion in two planes for normal-shear loading (mean error ± SD: 4.6 ± 0.8% for the finite element data versus the criterion). This multiaxial yield criterion in normalized-strain space can be used to describe the complete 3D multiaxial failure behavior of human trabecular bone across a wide range of bone volume fraction, mechanical anisotropy, and microarchitecture.

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