Modeling the curvature and interface shear stress of GaN-sapphire system

2016 ◽  
Vol 30 (08) ◽  
pp. 1650099
Author(s):  
Jia Li ◽  
Junjie Shi ◽  
Jiejun Wu ◽  
Huizhao Liu
Keyword(s):  
Shear Stress ◽  
Sapphire Substrate ◽  
Uniform Thickness ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
Stress Changes ◽  
Circular System ◽  
Gan Film

The curvature and interface shear stress of GaN-sapphire system are studied by establishing the mechanical equations based on two main assumptions: (a) the thickness of GaN film can be compared to the thickness of sapphire substrate, and (b) the thickness of GaN film is non-uniform. Our results show that the curvature of GaN-sapphire system is a variable within the whole circular system. The interface shear stress changes direction around at the middle of radius for the circular system, and the curvature have an important effect on the interface shear stress due to the consideration of non-uniform thickness for GaN film.

Interface Shear Stress of Concrete Beams Strengthened with FRP in Salt Water

2012 ◽  
Vol 446-449 ◽  
pp. 3499-3502
Author(s):  
Chen Zhao ◽  
Pei Yan Huang ◽  
Zhong Song Chen
Keyword(s):  
Shear Stress ◽  
Concrete Beam ◽  
Salt Water ◽  
Interfacial Shear Stress ◽  
Interfacial Properties ◽  
Interfacial Shear ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
Bond Slip ◽  
Relationship Model

Based on existing methods and results of other research, the bond-slip relationship model is given and the distrubition of shear stress of concrete beam strengthened by FRP in salt water is derived. Through a specific example to analyze the distribution of interfacial shear stress, and the different effects caused by different aggressive environment on the interfacial properties. The results show that: 1) Interfacial shear stress will sharply reduce with increasing distance from the end; 2) Different environments have different effects on the interface properties of FRP strengthened beams. Salt water erosion influnce the interfacial properties of FRP strengthened beams significantly.

scholarly journals A Coupled 1D Film Hydrodynamics and Core Gas Flow Model for Air-Oil Flows in Aero-Engine Bearing Chambers

2017 ◽  
Author(s):  
B. Kakimpa ◽  
H. P. Morvan ◽  
S. Hibberd
Keyword(s):  
Shear Stress ◽  
Operating Conditions ◽  
Engine Oil ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
Oil Film ◽  
Film Model ◽  
Aero Engine ◽  
Film Interface ◽  
Engine Bearing

A robust 1D film hydrodynamic model has been sequentially coupled with a 1D core gas model and used to predict the instantaneous mean core gas speed, film interface shear stress and liquid film distribution within an idealised bearing chamber. This novel approach to aero-engine bearing chamber simulation provides a predictive tool that can be used for the fast and reliable exploration of a set of bearing chamber design and operating conditions characterised by the: chamber dimensions, air/oil fluid properties, shaft speed, sealing air flows, oil feed rates and sump scavenge ratios. A preliminary validation of the model against available bearing chamber flow measurements from literature shows good agreement. The model represents a significant step change in predictive capabilities for aero-engine oil system flows compared to previous semi-empirical models. The bearing chamber is idealised as a one-dimensional (2D) domain with a predominantly azimuthal flow in both the rotational oil film and core gas such that axial components may be ignored. A 1D system of depth-averaged film hydrodynamics equations is used to predict oil film thickness and mean speed distributions in the azimuthal direction under the influence of interface shear, gravity, pressure gradient and surface tension forces. The driving shear stress in the film model is obtained from the 1D core-gas model based on an azimuthal gas momentum conservation equation which is coupled to the film model through the interface shear stress and film interface velocity.

Interface Shear Stress Analysis of Concrete Beam Strengthened with CFRP

2011 ◽  
Vol 71-78 ◽  
pp. 1348-1353 ◽  
Author(s):  
Yong Chao Zhou ◽  
Tie Jun Sun
Keyword(s):  
Shear Stress ◽  
Stress Analysis ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Bending Moment ◽  
Failure Model ◽  
Interface Shear ◽  
Concentrated Load ◽  
Interface Shear Stress ◽  
Basic Assumptions

Based on elastic theory, the four basic assumptions and the failure model of concrete beams strengthened with CFRP, deduced the formulae about the concrete beams strengthened with CFRP with concentrated load. Results show the biggest interface shear stress is at the at the anchor end, it not only relate to the material property of CFRP and concrete, but also to the thickness, width and bending moment at the anchor end etc.. Reducing CFRP stiffness and thickness or increasing viscose layer thickness, these can reduce the maximum interface shear stress at the end of anchoring.

scholarly journals CONFIGURATIONAL FORCE EXERTED ON AN INHOMOGENEITY BY A PILEUP OF SCREW DISLOCATIONS

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Vlado A. Lubarda
Keyword(s):  
Shear Stress ◽  
Configurational Forces ◽  
Bimaterial Interface ◽  
Dislocation Pileup ◽  
Configurational Force ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
Screw Dislocations ◽  
Material Inhomogeneity ◽  
Circular Inhomogeneity

Configurational forces exerted by a screw dislocation pileup on a circular inhomogeneity or a bimaterial interface are determined for a given number of dislocations, the level of remotely applied stress, and a specified degree of material inhomogeneity. The interface shear stress is also evaluated and discussed.

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