Time-dependent creep stress redistribution analysis of thick-walled FGM spheres subjected to an internal pressure and a uniform temperature field is investigated. The material creep and mechanical properties through the radial graded direction are assumed to obey the simple power-law variation throughout the thickness. Total strains are assumed to be the sum of elastic, thermal and creep strain...

This paper describes high temperature cyclic elastic-plastic testing of XN40F material for application to the life prediction of superplastic forming (SPF) tools. Cyclic plasticity material constitutive constants are identified from the high temperature tests across the range of 20C to 900C for representative predicted die conditions. These material constants are implemented within a transient,...

In this article, the time-dependent stress redistribution analysis of magneto-electro-elastic (MEE) thick-walled sphere subjected to mechanical, electrical, magnetic and uniform temperature gradient as well as moisture concentration gradient is presented. Combining constitutive equations of MEE with stress-strain relations as well as strain-displacement relations results in obtaining a differen...

In this article, the problem of time-dependent stress redistribution of a piezomagnetic rotating thick-walled cylinder under an axisymmetric hygro-thermo-magneto-electro-mechanical loading is analyzed analytically for the condition of plane strain. Using the constitutive equations, a differential equation is found in which there are creep strains. Primarily, eliminating creep strains, an analyt...

The application of the finite element method to the inelastic analysis of structures and continua has received considerable attention over the last fifteen years [ 1-21 ]. To a large extent, this effort has been motivated by the need to safety and economically predict material response under conditions of extreme mechanical and thermal loading. Some examples are the design and analysis of press...

We studied the elastic moduli, ductile creep behavior, and brittle strength of shale-gas reservoir rocks from Barnett, Haynesville, Eagle Ford, and Fort St. John shale in a series of triaxial laboratory experiments. We found a strong correlation between the shale compositions, in particular, the volume of clay plus kerogen and intact rock strength, frictional strength, and viscoplastic creep. V...

For description of the visco-elastic behavior of soft biological tissues, Fung proposed a visco-elastic model formulated in terms of a relaxation function and corresponding relaxation spectrum. For the corresponding creep function, Fung proposed an expression which needs correction to obtain a consistent formulation. This creep function and the corresponding creep spectrum are derived in this n...

Fractional calculus has been proved to be very effective in representing the visco-elastic relaxation response of materials with memory such as polymers. Moreover, modeling temperature dependency material functions thermo-visco-elasticity, standard time–temperature superposition principle is known ineffective most cases (thermo-rheological complexity). In this work, a novel finite element formu...

electro-thermo-elastic stress analysis of piezoelectric polymeric thick-walled cylinder reinforced by boronnitride nanotubes (bnnts) subjected to electro-thermo-mechanical fields is presented in this article. the electro-thermo-elastic properties of piezoelectric fiber reinforced composite (pefrc) was studied by a modified xy micromechanical model capable of exhibiting full coupling relation be...