This paper presents a methodology to determine simultaneously (a) the flow stress at high deformation rates and temperatures that are encountered in the cutting zone, and (b) the friction at the chip–tool interface. This information is necessary to simulate high-speed machining using FEM based programs. A flow stress model based on process dependent parameters such as strain, strain-rate and te...

The hot compression tests were carried on X45CrNiW189 valve steel (X45) in the temperature range of 1000– 1200 °C and the strain rate range of 0.004 – 0.5 s-1 in order to study the high temperature softening behavior of this steel. For the exact prediction of flow stress, the effective stress-effective strain curves were obtained from experiments under various conditions. On the basis of experi...

there are various parameters that affect stability and expansion of failure zones in under pressure tunnels. among the important parameters that affect failure zones around the tunnels are cohesion and internal friction angle of the rock mass. in addition, the cross sectional shape is the considerable point in failure distribution around the tunnels. the stress analysis method is one of the app...

Besides experimental methods, numerical simulations bring benefits and great opportunities to characterize and predict mechanical behaviors of materials especially at nanoscale. In this study, a nano-single crystal aluminum (Al) as a typical face centered cubic (FCC) metal was modeled based on molecular dynamics (MD) method and by applying tensile and compressive strain loadings its mechanical ...

For analysing dynamically loaded structures by means of the finite element method a dynamic constitutive material model is necessary to obtain reliable results. For this purpose dynamic tensile tests were performed with the fine grained steel 20MnMoNi 5 5 (A508 CI. 3) and the austenitic steel X6CrNi 18 11'at different velocities. Smooth round bar specimens of different geometries were used. Dis...

In this paper, we investigate a relatively new method for determining three-dimensional sub-surface residual stress (Ueda, 1975). This hybrid experimental/analytical method determines the source of residual stress by sectioning and strain measurement, and then uses it to deduce residual stress in the original body. When certain assumptions about the spatial distribution of the source of residua...

BACKGROUND The Nuss procedure corrects pectus excavatum using a pre-bent bar that generates stress on the chest wall. To investigate the biomechanical effects after the Nuss procedure, we designed a three-dimensional finite element analysis model to analyze the distribution of stress and strain induced in the chest wall. METHODS Three patients with pectus excavatum aged 8, 7, and 7 years, wer...