Rigid-lid approximation is usually used to replace the free surface in scour simulation. The influence of the rigid lid assumption on the prediction precision of scour hole in steady flow is studied in this paper. Firstly, a local scour model was constructed based on the open sources Computational Fluid Dynamics (CFD) model OpenFOAM, where both the bed load and suspended load were considered. I...

In order to achieve integrated condition in the girth welding of high pressure natural gas transmission pipelines, the weld zones and its surrounding area should have good mechanical properties. Residual stresses are an important defect especially in the girth welding of the pipeline. In this study, two API X70 steel pipes (with spiral seam weld) of 56 inches outside diameter and 0.780 inch wal...

Gate degradation in high electron mobility transistors (HEMTs) under OFF-state stress results from the high electric field near the gate edge. We investigate the evolution of this field over time in AlGaN/ GaN HEMTs upon OFF-state stress using a combination of electroluminescence (EL) microscopy and spectroscopy. EL analysis suggests that the electric field at the sites of generated surface def...

This paper investigates the free edge effect on the stress field of a carbon fiber, which is embedded into an epoxy matrix. The fiber is assumed to possess cylindrical symmetry and to be transversely isotropic. The matrix is assumed to be of an isotropic material. The stress field is induced by a uniform tension applied on the matrix at points far away from the fiber surface. The displacement a...

Due to high surface-to-volume ratio of nanoscale structures, surface stress effects have a significant influence on their behavior. In this paper, a two-dimensional problem for an elastic layer that is bonded to a rigid substrate and subjected to an inclined concentrated line load acting on the surface of the layer is investigated based on Gurtin-Murdoch continuum model to consider surface stre...

Background and Objective: Skin ulcers and their slow healing are considered as one of the important medical aspects. Nowadays, various antibiotics and materials are used to accelerate the wound healing process. One of the methods taken in the field of wound healing is using ozone. On the other hand, one of the factors that hurt the speed of wound healing is stress. Therefore, the present study ...

The effect of the ultrasonic surface rolling process (USRP) on the rotary bending fretting fatigue (FF) of Ti-6Al-4V alloy was investigated. The reason for the USRP's ability to improve the FF resistance of Ti-6Al-4V alloy was studied. The results revealed that the USRP induced a compressive residual stress field with a depth of 530 μm and a maximum residual stress of -930 MPa. Moreover, the su...

It has been pointed out by some researchers that road pavements are subjected to vertical stress due to vehicles on them as well as shear stress at the time of braking or acceleration of vehicles. In this paper, the results of elastic analysis to obtain the rigorous solution for an elastic two-layer system subjected to surface shear stress are described and it is shown that the effect of shear ...