Tensile yield-stress behavior of glassy polymers

1969 ◽  
Vol 7 (4) ◽  
pp. 735-742 ◽  
Author(s):  
C. Bauwens-Crowet ◽  
J. C. Bauwens ◽  
G. Homès
Keyword(s):  
Yield Stress ◽  
Glassy Polymers ◽  
Tensile Yield Stress ◽  
Stress Behavior

scholarly journals Description of Residual Stress and Strain Fields in FGM Hollow Disc Subject to External Pressure

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 440 ◽  
Author(s):  
Stanislav Strashnov ◽  
Sergei Alexandrov ◽  
Lihui Lang
Keyword(s):  
Elastic Modulus ◽  
Plastic Strain ◽  
Yield Stress ◽  
Plastic Region ◽  
External Pressure ◽  
Plastic Strain Rate ◽  
Constant Thickness ◽  
Stress And Strain ◽  
Strain Fields ◽  
Tensile Yield Stress

Elastic/plastic stress and strain fields are obtained in a functionally graded annular disc of constant thickness subject to external pressure, followed by unloading. The elastic modulus and tensile yield stress of the disc are assumed to vary along the radius whereas the Poisson’s ratio is kept constant. The flow theory of plasticity is employed. However, it is shown that the equations of the associated flow rule, which are originally written in terms of plastic strain rate, can be integrated with respect to the time giving the corresponding equations in terms of plastic strain. This feature of the solution significantly facilitates the solution. The general solution is given for arbitrary variations of the elastic modulus and tensile yield stress along the radial coordinate. However, it is assumed that plastic yielding is initiated at the inner radius of the disc and that no other plastic region appears in the course of deformation. The solution in the plastic region at loading reduces to two ordinary differential equations. These equations are solved one by one. Unloading is assumed to be purely elastic. This assumption should be verified a posteriori. An illustrative example demonstrates the effect of the variation of the elastic modulus and tensile yield stress along the radius on the distribution of stresses and strains at the end of loading and after unloading. In this case, it is assumed that the material properties vary according to power-law functions.

Dislocation Structure, Phase Stability and Yield Stress Behavior of Ultra-High Temperature L12 Intermetallics: Combined First Principles-Peierls-Nabarro Approach

2004 ◽  
Vol 842 ◽  
Author(s):  
Oleg Y. Kontsevoi ◽  
Yuri N. Gornostyrev ◽  
Arthur J. Freeman
Keyword(s):  
High Temperature ◽  
Mechanical Behavior ◽  
Yield Stress ◽  
Dislocation Structure ◽  
First Principles ◽  
Platinum Group Metals ◽  
Intermetallic Alloys ◽  
Stress Behavior ◽  
Restoring Forces ◽  
Ultra High Temperature

ABSTRACTWe present results of comparative studies of the dislocation properties and the mechanical behavior for a class of intermetallic alloys based on platinum group metals (PGM) which are being developed for ultra-high temperature applications: Ir3X and Rh3X (where X = Ti, Zr, Hf, V, Nb, Ta). For the analysis of dislocation structure and mobility, we employ a combined approach based on accurate first-principles calculations of the shear energetics and the modified semi-discrete 2D Peierls-Nabarro model with an ab-initio parametrization of the restoring forces. Based on our analysis of dislocation structure and mobility, we provide predictions of temperature yield stress behavior of PGM-based intermetallics, show that their dislocation properties are closely connected with features of the electronic structure and the L12 → D019 structural stability, and demonstrate the dramatic difference in dislocation structure and the mechanical behavior between PGM alloys with IVA and VA group elements.

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