We study the effect of physical aging on the mechanical properties of a model polymer glass using molecular dynamics simulations. The creep compliance is determined simultaneously with the structural relaxation under a constant uniaxial load below yield at constant temperature. The model successfully captures universal features found experimentally in polymer glasses, including signatures of me...

The ultimate objective of this research project is to develop creep damage constitutive equations for low Cr-Mo alloy and its weldment under low stress (0.2-0.4 yield stress, ��). This paper summarizes a critical analysis on the cavity nucleation and growth and the deformation mechanisms and creep damage evolution characteristics at low stress with temperature ranging from 450 °C to 650 °C, in ...

In thermoelectric devices, Bi2Te3 must be able to operate under high temperature gradients for very long times (years) without appreciable deformation, while being subjected to stresses created by internal thermal mismatch and external forces (e.g., vibrations). The deformation rate of cast, coarsegrained Bi2Te3 was measured under uniaxial compressive stresses from 2 to 16 MPa at temperatures b...

Bolted joints are used widely in mechanical design and represent a weak link in a system where loss of joint clamping force can lead to degraded product performance or human injury. To meet current market demands, designers require reliable material data and analysis tools for their industry specific materials. The viscoelastic response of bolted aluminum joints used in the small die-cast engin...

abstract- in this study, texture profile analysis and a creep test were used to determine the textural quality attributes of fish protein isolates and conventional surimi. these isolates were made from raw materials obtained from filleting processes of silver carp (hypophthalmichthys molitrix) using acid and alkaline aided treatments. texture profile analysis was performed in order to obtain ha...

This paper presents a constitutive thermoviscoelastic model for thin films of linear low-density polyethylene subject to strains up to yielding. The model is based on the free volume theory of nonlinear thermoviscoelasticity, extended to orthotropic membranes. An ingredient of the present approach is that the experimentally inaccessible out-of-plane material properties are determined by fitting...

In vivo measurements of the viscoelastic properties of breast tissue are described. Ultrasonic echo frames were recorded from volunteers at 5 fps while applying a uniaxial compressive force (1-20 N) within a 1 s ramp time and holding the force constant for up to 200 s. A time series of strain images was formed from the echo data, spatially averaged viscous creep curves were computed, and viscoe...

When sufficient force is applied to a glassy polymer, it begins to deform through movement of the polymer chains. We used an optical photobleaching technique to quantitatively measure changes in molecular mobility during the active deformation of a polymer glass [poly(methyl methacrylate)]. Segmental mobility increases by up to a factor of 1000 during uniaxial tensile creep. Although the Eyring...

Tests of cylindrical specimens of O. 75 in. diameter up to 300.000 psi axial compression stress have been conducted for hardened portland cement paste as well as concrete with !Is in. aggregate. The specimens tightly fit into a cylindrical cavity in a pressure vessel and are loaded axially by a hard piston. The pressure vessel is very stiff, forcing the lateral expansion of specimens to be so s...