A Comparison of Deformation and Flow Theories Under Dynamic Loading Conditions

1978 ◽  
Vol 45 (2) ◽  
pp. 431-433
Author(s):  
P. C. Upadhyay ◽  
V. K. Stokes
Keyword(s):  
Deformation Theory ◽  
Numerical Solutions ◽  
Infinite Plate ◽  
Theory Model ◽  
Loading Conditions ◽  
Constant Acceleration ◽  
Stress Strain Relation ◽  
Flow Theories ◽  
Hole Boundary ◽  
Dynamic Loading Conditions

Numerical solutions have been obtained for the problem of the dynamic expansion of a circular hole in an infinite plate, due to the imposition of a constant acceleration at the hole boundary, for a deformation theory model based on the Ramberg-Osgood stress-strain relation. In order to assess the validity of using deformation theories for problems in which dynamic plastic deformations may occur under nonproportional loading conditions, these solutions have been compared with those for the equivalent flow theory model.

The Dynamic Hole Expansion Problem for a Plate of Elastic-Perfectly Plastic Material

1978 ◽  
Vol 45 (4) ◽  
pp. 961-963
Author(s):  
P. C. Upadhyay ◽  
V. K. Stokes
Keyword(s):  
Circular Hole ◽  
Numerical Solutions ◽  
Plastic Material ◽  
Plastic Region ◽  
Infinite Plate ◽  
Tangential Component ◽  
Constant Acceleration ◽  
Perfectly Plastic ◽  
Hole Boundary ◽  
Elastic Perfectly Plastic

Numerical solutions have been obtained for the problem of the dynamic expansion of a circular hole in an infinite plate of elastic-perfectly plastic material, due to the imposition of a constant acceleration at the hole boundary, for three different materials. It has been shown that Freiberger’s assumption, concerning the vanishing of the tangential component of stress in the plastic region, is not valid.

On the Dynamic Expansion of a Circular Hole in an Infinite Plate of Rate-Sensitive Plastic Material

1978 ◽  
Vol 45 (1) ◽  
pp. 67-72 ◽  
Author(s):  
P. C. Upadhyay ◽  
V. K. Stokes
Keyword(s):  
Circular Hole ◽  
Exponential Type ◽  
Material Properties ◽  
Method Of Characteristics ◽  
Numerical Solutions ◽  
Plastic Material ◽  
Infinite Plate ◽  
Constant Acceleration ◽  
Plastic Materials ◽  
Wide Range

The dynamic expansion of a circular hole in an infinite plate has been considered for rate-sensitive plastic materials by using an elastic-visco-perfertly plastic model of the exponential type. Numerical solutions have been obtained, by the method of characteristics, for the case when the hole is subjected to a constant acceleration. Solutions have been presented in the form of nondimensional plots covering a wide range of material properties and accelerations.

Development and Verification of a Dynamic TKR Model

2002 ◽  
Author(s):  
Jason P. Halloran ◽  
Anthony J. Petrella ◽  
Paul J. Rullkoetter
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Dynamic Loading ◽  
Soft Tissues ◽  
Dynamic Models ◽  
Total Joint Replacement ◽  
Fe Model ◽  
Loading Conditions ◽  
Dynamic Loading Conditions

The success of current total knee replacement (TKR) devices is contingent on the kinematics and contact mechanics during in vivo activity. Indicators of potential clinical performance of total joint replacement devices include contact stress and area due to articulations, and tibio-femoral and patello-femoral kinematics. An effective way of evaluating these parameters during the design phase or before clinical use is via computationally efficient computer models. Previous finite element (FE) knee models have generally been used to determine contact stresses and/or areas during static or quasi-static loading conditions. The majority of knee models intended to predict relative kinematics have not been able to determine contact mechanics simultaneously. Recently, however, explicit dynamic finite element methods have been used to develop dynamic models of TKR able to efficiently determine joint and contact mechanics during dynamic loading conditions [1,2]. The objective of this research was to develop and validate an explicit FE model of a TKR which includes tibio-femoral and patello-femoral articulations and surrounding soft tissues. The six degree-of-freedom kinematics, kinetics and polyethylene contact mechanics during dynamic loading conditions were then predicted during gait simulation.

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