In this paper, we estimate the reliability of a parallel system with two components. We assume that the strengths of these components follow bivariate pareto (BVP) distribution proposed by Veenus and Nair(1994). These two components are subjected to either two independent stresses or common stress which are ( is ) independent of strengths of two components. We assume that the distribution of st...

In this paper, a simple cracked beam under vertical pressure is considered. Stress intensity factor, normal, and shear stresses (at the tip of the crack) are calculated with finite element software. Results are compared when there is contact between crack surfaces with different direction of pressure, and when there is no contact. Results show that stress intensity factors can be implemented fo...

in this paper, the nonlinear free vibrations of thin symmetric and non-symmetric cross-ply composite plates subjected to biaxial initial stresses are investigated. because of their excellent properties such as specific strength and specific stiffness, composite plates have wide applications in aerospace and mechanical structures. based on von-karman's strain-displacement relations and using gal...

A microstructural investigation of stishovite-bearing quartzite from the Vredefort meteorite impact site in South Africa reveals features that are attributed to shock deformation. These include abundant mechanically induced Dauphiné twinning, rhombohedral deformation lamellae and associated residual stresses. Mechanical twins were identified with SEM-EBSD. Residual stresses are derived from equ...

In this study acoustic emission (AE) techniques were investigated to determine in situ rock stress from rock cores. The stresses were estimated from the AE behaviour and compared with the values calculated using conventional Hollow Inclusion (HI) cells. Stresses in three different directions such as normal to bedding and parallel to the strike and dip of bedding were determined from the rock co...

The  ow patterns and stresses on the wall in a moving granular bed with eccentric discharge were investigated experimentally. The  ow pattern histories of granular solids in the moving bed were recorded using a digital camcorder. The image processing system included a frame grabber. A new pressure gauge for simultaneously measuring the normal and shear stresses of granular solids was used. Du...

A two-phase scheme for accurate predictions of interlaminar stresses in laminated plate and shell structures has been addressed in this study. A modified superconvergent patch recovery (MSPR) technique has been utilized to obtain accurate nodal in-plane stresses which are subsequently used with the thickness integration of the three-dimensional equilibrium equations to evaluate the transverse s...

The expression levels of three chitinase genes in Arabidopsis thaliana, AtChiA (class III), AtChiB (class I), and AtChiV (class IV), were examined under various stress conditions by semi-quantitative RT-PCR. Under normal growth conditions, the AtChiB and AtChiV genes were expressed in most organs of Arabidopsis plants at all growth stages, whereas the AtChiA gene was not expressed at all. The c...

in this research, the effect of tension wood formation in populus nigra on its anatomical characteristics was studied. vessel element and ray frequency (n/mm²), vessel diameter and ray dimensions were measured in both normal and tension wood. furthermore, the formation of gelatinous layer (g-layer) in the fibers of tension wood was studied. the results showed that the vessel proportion and diam...