Material properties of femoral cancellous bone in axial loading

1980 ◽  
Vol 97 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Antonius Rohlmann ◽  
Hans Zilch ◽  
Georg Bergmann ◽  
Reinhard Kolbel
Keyword(s):  
Cancellous Bone ◽  
Material Properties ◽  
Axial Loading

Material Properties of Cancellous Bone in Repetitive Axial Loading

1985 ◽  
Vol 14 (4) ◽  
pp. 173-177 ◽  
Author(s):  
Frank Linde ◽  
Ivan Hvid ◽  
Niels Chr. Jensen
Keyword(s):  
Cancellous Bone ◽  
Material Properties ◽  
Axial Loading

Material properties of femoral cancellous bone in axial loading

1980 ◽  
Vol 97 (4) ◽  
pp. 257-262 ◽  
Author(s):  
Hans Zilch ◽  
Antonius Rohlmann ◽  
Georg Bergmann ◽  
Reinhard K�lbel
Keyword(s):  
Cancellous Bone ◽  
Material Properties ◽  
Axial Loading

Buckling of Standing Tapered Timoshenko Columns with Varying Flexural Rigidity Under Combined Loadings

2016 ◽  
Vol 16 (06) ◽  
pp. 1550017 ◽  
Author(s):  
D.-L. Sun ◽  
X.-F. Li ◽  
C. Y. Wang
Keyword(s):  
Cross Section ◽  
Timoshenko Beam ◽  
Material Properties ◽  
Flexural Rigidity ◽  
Axial Loading ◽  
Beam Theory ◽  
Shear Rigidity ◽  
Initial Value ◽  
Buckling Loads ◽  
The Stability

The stability of a nonuniform column subjected to a tip force and axially distributed loading is investigated based on the Timoshenko beam theory. An emphasis is placed on buckling of a standing column with varying cross-section and variable material properties under self-weight and tip force. Four kinds of columns with different taper ratios are analyzed. A new initial value method is suggested to determine critical tip force and axial loading at buckling. The effectiveness of the method is confirmed by comparing our results with those for Euler–Bernoulli columns for the case of sufficiently large shear rigidity. The effects of shear rigidity, taper ratio, and gravity loading on the buckling loads of a heavy standing or hanging column are examined.

scholarly journals Transversely Isotropic Elasticity Imaging of Cancellous Bone

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Spencer W. Shore ◽  
Paul E. Barbone ◽  
Assad A. Oberai ◽  
Elise F. Morgan
Keyword(s):  
Mechanical Properties ◽  
Inverse Problem ◽  
Cancellous Bone ◽  
Material Properties ◽  
Transversely Isotropic ◽  
Elasticity Imaging ◽  
Elastic Parameters ◽  
Displacement Fields ◽  
Isotropic Materials ◽  
Isotropic Elasticity

To measure spatial variations in mechanical properties of biological materials, prior studies have typically performed mechanical tests on excised specimens of tissue. Less invasive measurements, however, are preferable in many applications, such as patient-specific modeling, disease diagnosis, and tracking of age- or damage-related degradation of mechanical properties. Elasticity imaging (elastography) is a nondestructive imaging method in which the distribution of elastic properties throughout a specimen can be reconstructed from measured strain or displacement fields. To date, most work in elasticity imaging has concerned incompressible, isotropic materials. This study presents an extension of elasticity imaging to three-dimensional, compressible, transversely isotropic materials. The formulation and solution of an inverse problem for an anisotropic tissue subjected to a combination of quasi-static loads is described, and an optimization and regularization strategy that indirectly obtains the solution to the inverse problem is presented. Several applications of transversely isotropic elasticity imaging to cancellous bone from the human vertebra are then considered. The feasibility of using isotropic elasticity imaging to obtain meaningful reconstructions of the distribution of material properties for vertebral cancellous bone from experiment is established. However, using simulation, it is shown that an isotropic reconstruction is not appropriate for anisotropic materials. It is further shown that the transversely isotropic method identifies a solution that predicts the measured displacements, reveals regions of low stiffness, and recovers all five elastic parameters with approximately 10% error. The recovery of a given elastic parameter is found to require the presence of its corresponding strain (e.g., a deformation that generates ɛ12 is necessary to reconstruct C1212), and the application of regularization is shown to improve accuracy. Finally, the effects of noise on reconstruction quality is demonstrated and a signal-to-noise ratio (SNR) of 40dB is identified as a reasonable threshold for obtaining accurate reconstructions from experimental data. This study demonstrates that given an appropriate set of displacement fields, level of regularization, and signal strength, the transversely isotropic method can recover the relative magnitudes of all five elastic parameters without an independent measurement of stress. The quality of the reconstructions improves with increasing contrast, magnitude of deformation, and asymmetry in the distributions of material properties, indicating that elasticity imaging of cancellous bone could be a useful tool in laboratory studies to monitor the progression of damage and disease in this tissue.

Homogenization and Stress Analysis of Multilayered Composite Offshore Production Risers

2013 ◽  
Vol 81 (3) ◽  
Author(s):  
X. S. Sun ◽  
Y. Chen ◽  
V. B. C. Tan ◽  
R. K. Jaiman ◽  
T. E. Tay
Keyword(s):  
Stress Analysis ◽  
Elastic Constants ◽  
Material Properties ◽  
Axial Loading ◽  
Stress And Strain ◽  
Multilayered Composite ◽  
External Pressures ◽  
Complex Models ◽  
Composite Cylinders ◽  
Stress Analyses

An approach for stress analysis of multilayered composite cylinders is proposed for the analysis of new composite risers used in deep-water oil production of offshore petroleum industries. Risers essentially comprise long cylindrical sections connected end-to-end. In the formulation, only stresses and strains that are continuous through the thickness of the multilayered composite risers are taken to be equal to reported solutions for homogenous orthotropic hollow cylinders using homogenized material properties. These stress and strain solutions are then used to calculate the remaining discontinuous stresses and strains from the material properties of individual layers of materials. The homogenized elastic constants of cylindrically orthotropic composite risers are derived from force-deformation equivalence, taking into account the stress and strain distributions in each layer. Four typical loading conditions are considered in the stress analysis, namely, internal and external pressures, axial loading, bending, and torsion. Examples of homogenized elastic constants and stress analyses of composite cylindrical structures with different layups and materials are presented to demonstrate the application of the proposed method. The results compared very favorably with those from other solutions. This method provides practical benefits for the design and analysis of composite risers. Because there is no requirement to explicitly enforce interfacial continuity in this method, stress analyses of composite cylinders with many layers of different fiber angles or materials can be carried out efficiently. The homogenized elastic constants can greatly expedite the analysis of entire composite riser systems by replacing complex models of riser sections with homogenized riser sections.

Effects of Tapping on the Holding Strength of Cancellous Bone Screws

1992 ◽  
Vol 05 (01) ◽  
pp. 10-12 ◽  
Author(s):  
J. F. Surowiak ◽  
J. Schatzker ◽  
T. C. Hearn
Keyword(s):  
Cancellous Bone ◽  
Material Properties ◽  
Tensile Force ◽  
Testing Machine ◽  
Bone Screws ◽  
The Other ◽  
Materials Testing ◽  
Host Medium ◽  
Pilot Hole ◽  
Maximum Value

SummaryThe purpose of the study was to determine whether tapping affects the holding strength of cancellous bone screws in soft material. Paired extraction tests were conducted using 6.5 mm cancellous bone screws in porous polyurethane foam. One member of each pair had a pre-tapped pilot hole, the other was inserted in a self-tapping manner. The maximum value of tensile force during extraction with a servohydraulic materials testing machine was recorded as the screw holding strength.Comparison of the holding strengths between the pre-tapped and self-tapping groups revealed a lower mean holding strength for the pre-tapped group (p <0.05). This result contrasts with previous studies which showed that pre-tapping increases the holding strength of bone screws in relatively stronger materials. The effect of tapping on the holding strength of bone screws is therefore dependant on the material properties of the host medium.This study examined the effect of tapping the pilot hole on the extraction strength of 6.5 mm cancellous bone screws in soft, synthetic cancellous material. In contrast with previous studies in stronger materials, it was found that tapping significantly reduces the holding strength of bone screws. The effects of tapping depend on the material properties of the host medium.

Regional Differences in Mechanical and Material Properties of Femoral Head Cancellous Bone in Health and Osteoarthritis

2002 ◽  
Vol 71 (3) ◽  
pp. 227-234 ◽  
Author(s):  
S.J. Brown ◽  
P. Pollintine ◽  
D.E. Powell ◽  
M.W.J. Davie ◽  
C.A. Sharp
Keyword(s):  
Femoral Head ◽  
Cancellous Bone ◽  
Material Properties ◽  
Regional Differences

Orthogonal relationships between ultrasonic velocity and material properties of bovine cancellous bone

1996 ◽  
Vol 18 (5) ◽  
pp. 373-381 ◽  
Author(s):  
C.F. Njeh ◽  
R. Hodgskinson ◽  
J.D. Currey ◽  
C.M. Langton
Keyword(s):  
Ultrasonic Velocity ◽  
Cancellous Bone ◽  
Material Properties
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