“In Vivo” Determination of Macroscopic Biological Material Properties

1975 ◽  
Vol 97 (4) ◽  
pp. 350-356 ◽  
Author(s):  
E. R. Garner ◽  
D. O. Blackketter
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Material Properties ◽  
Biological Material ◽  
Soft Tissues ◽  
Three Dimensional ◽  
Element Model ◽  
Harmonic Excitation ◽  
Analytical Technique

This paper describes an experimental-analytical technique for determining the in-vivo macroscopic biological material properties of the human forearm. The technique utilizes the experimentally determined steady-state response of the forearm to a harmonic excitation in the 100 to 1000 Hertz band and a non-symmetric three-dimensional finite element model of the forearm. The “in-vivo macroscopic material properties” were determined by adjusting the material properties of the finite element model until there was a minimum of difference between the response of the finite element and the response found experimentally in the 100 to 1000 Hertz band. Both the soft tissues and the hard tissues were modeled as viscoelastic materials.

scholarly journals On the Identification of Elastic Moduli of In-Service Rail by Ultrasonic Guided Waves

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1769
Author(s):  
Liqiang Zhu ◽  
Xiangyu Duan ◽  
Zujun Yu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Material Properties ◽  
Guided Waves ◽  
Three Dimensional ◽  
Element Model ◽  
Guided Wave ◽  
Accurate Information ◽  
Profile Changes ◽  
Three Dimensional Finite Element

Non-destructive rail testing and evaluation based on guided waves need accurate information about the mode propagation characteristics, which can be obtained numerically with the exact material properties of the rails. However, for rails in service, it is difficult to accurately obtain their material properties due to temperature fluctuation, material degradation and rail profile changes caused by wear and grinding. In this study, an inverse method is proposed to identify the material elastic constants of in-service rails by minimizing the discrepancy between the phase velocities predicted by a semi-analytical finite element model and those measured using array transducers attached to the rail. By selecting guided wave modes that are sensitive to moduli but not to rail profile changes, the proposed method can make stable estimations for worn rails. Numerical experiments using a three-dimensional finite element model in ABAQUS/Explicit demonstrate that reconstruction accuracies of 0.36% for Young’s modulus and 0.87% for shear modulus can be achieved.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

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