This study deals with the relation between the microstructure of semi-crystalline polymers and their intrinsic deformation and fracture behaviour. For this purpose, the deformation and failure of well-characterised PET, PE and PP samples have been investigated thoroughly. Compression tests on amorphous and cold crystallised PET showed that the strain hardening remained unchanged, despite the de...

conclusions pci was accompanied by some improvement in left atrial deformation indices as assessed by tissue doppler imaging. revascularization can, therefore, improve patient outcome. results regarding changes in left trial functional parameters after pci, those such as the strain of the septal wall and the anterior and inferior walls and the strain rate of the anterior and lateral walls signi...

It is well known that size effects are present in plasticity with the observation that smaller being the stronger. This effect is attributed to the presence of geometrically necessary dislocations (GNDs). The hardening associated to GNDs can be separated in two groups: energetic and dissipative. The fi rst is associated with defect energy and different defi nitions for it are possible. In all c...

the present study assesses the seismic performance of steel moment resisting frames (smfs) retrofitted with different bracing systems. two structural configurations were utilized: ordinary concentrically braces (ocbfs), buckling-restrained braces (brbfs). a 7-story and 18-story steel perimeter smfs were designed with insufficient lateral stiffness to satisfy code drift limitations in high seism...

Linear polypropylene (PP)—composed of long polymer chains devoid of branches or crosslinked structure—and blends of PP with olefinic elastomers are widely used in the automotive and packaging industries. What makes foams produced with these materials of growing interest is their potential to replace the prevalent thermoset polyurethane foams which are not recyclable. However, the production of ...

Neck retardation in stretching of ductile materials is promoted by strain hardening, strain-rate hardening and inertia. Retardation is usually beneficial because necking is often the precursor to ductile failure. The interaction of material behavior and inertia in necking retardation is complicated, in part, because necking is highly nonlinear but also because the mathematical character of the ...

The thermomechanical problem involving simple shearing of a finite slab made of an isotropic and viscoplastic material is studied with the objective of finding the e&t of the strain hardening parameter, strain-rate hardening parameters, thermal softening coeflicient and thermal conductivity on the initiation and growth of adiabatic shear bands. The body is placed in a hard loading device, i.e. ...

Ni 3Al, an L12 structure intermetallic crystal, is the basic composition of the y' precipitates in nickel-based superalloys and is a major strengthening mechanism contributing to the superalloys' outstanding high-temperature mechanical properties. Many L12-structure crystals present unusual macroscopic mechanical properties, including the anomalous temperature-dependence of yield strength and s...

It has been reported for a long time that methane hydrate presents strain hardening, whereas the strength of normal ice weakens with increasing strain after an ultimate strength. However, the microscopic origin of these differences is not known. Here, we investigated the mechanical characteristics of methane hydrate and normal ice by compressive deformation test using molecular dynamics simulat...

Titanium foams of relative density ranging from 0.3 to 0.9 were produced by titanium powder sintering procedures and tested in uniaxial compression at strain rates ranging from 0.01 to 2,000 s. The material microstructure was examined by X-ray tomography and Scanning Electron Microscopy (SEM) observations. The foams investigated are strain rate sensitive, with both the yield stress and the stra...