in this paper, we consider an  i.e., multiple step-stress accelerated life testing (alt) experiment with unequal duration of time . it is assumed that the time to failure of a product follows rayleigh distribution with a log-linear relationship between stress and lifetime and also we assume a generalized khamis-higgins model for the effect of changing stress levels. taking into account that the...

PURPOSE The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implan...

physical modeling for study of deep foundations can be performed in simple chambers (1g), calibration chambers (cc), and centrifuge apparatus (ng). these common apparatus face certain limitations and difficulties. recently, frustum confining vessels (fcv) have been evolved for physical modeling of deep foundations and penetrometers. shaped as the frustum of a cone, this device applies steady pr...

In this study, two-dimensional finite element modeling was used to study the simultaneous effect of the cell shape and regular cell distribution on the anisotropy of the elastic properties of 316L stainless steel foam. In this way, the uniaxial compressive stress-strain curve was predicted using a geometric model and fully solid 316L stainless steel. The results showed that the elastic tangent ...

Tubular KT-joints are quite common in offshore structural design and despite the crucial role of stress concentration factors (SCFs) in evaluating the fatigue performance of tubular joints. However, the SCF distribution in internally ring-stiffened KT-joints have not been investigated and no design equation is currently available to determine the SCFs for this type of joint. In the present pape...

This study used particle swarm optimization (PSO) to determine the optimal values of effective design variables acting on the stress distribution around a quasi-triangular hole in an infinite orthotropic plate. These parameters were load angle, hole orientation, bluntness, fiber angle, and material properties, which were ascertained on the basis of an analytical method used by Lekhnitskii [3]. ...

In this paper, layerwise theory (LT) along with the first, second and third-order shear deformation theories (FSDT, SSDT and TSDT) are used to determine the stress distribution in a simply supported square sandwich plate subjected to a uniformly distributed load. Two functionally graded (FG) face sheets encapsulate an elastomeric core while two epoxy adhesive layers adhere the core to the face ...