نتایج جستجو برای: state creep model

تعداد نتایج: 2779884  

2002
X. Q. Shi Z. P. Wang W. Zhou H. L. J. Pang Q. J. Yang

In this study, a large number of creep tests were carried out to study the effect of stress level and testing temperature on the creep behavior of 63 Sn/37Pb solder in a systematic manner. Based on the dislocation controlled creep mechanism and Gibbs’ free-energy theory, a new creep constitutive model was proposed. The model was found to describe accurately the creep flow of the solder and to b...

Journal: :Bioresource technology 2010
Yanjun Xu Qinglin Wu Yong Lei Fei Yao

The creep behavior of bagasse-based composites with virgin and recycled polyvinyl chloride (B/PVC) and high density polyethylene (B/HDPE) as well as a commercial wood and HDPE composite decking material was investigated. The instantaneous deformation and creep rate of all composites at the same loading level increased at higher temperatures. At a constant load level, B/PVC composites had better...

F. Rahmani, R. Kamgar, R. Rahgozar,

The purpose of this study is to evaluate the long-term vertical deformations of segmented pre-tensioned concrete bridges by a new approach. It provides a practical and reliable method for calculating the amount of long-term deformation based on creep and shrinkage in segmented prestress bridges. There are various relationships for estimating the creep and shrinkage of concrete. The analytical r...

1979
James R. Rice

This paper discusses recent theoretical developments on fracture at elevated temperature in the presence of overall plastic (dislocation) creep. Two topics are considered: 1. Stress fields at tips of macroscopic cracks in creeping solids: Here consideration is given to the transient development of an effectively steady state of creep in a cracked body, following sudden load application for whic...

2012
Vahid Monfared

Two novel mathematical models based on polynomial function (PF) and boundary condition method (BCM) are presented for determination of shear stress in interface in steady state creep in short fiber composites under axial loading. Important novelty of this research is determination of shear stress in interface without using of shear lag and imaginary fiber technique (IFT) theories. In these appr...

Journal: :نشریه مهندسی عمران و نقشه برداری 0
ابوالفضل حسنی دانشگاه تربیت مدرس علی حیدری پناه دانشگاه تربیت مدرس

creep compliance is one of the fundamental tests of mechanistic- empirical flexible pavement design procedure in the aashto 2002 design guide. in this research, a new artificial neural network model for estimating the hma creep compliance with the generalization ability of r=0.949 has been developed successfully using feed forward multi layer perceptron artificial neural networks (anns) with le...

2016
Lili An Qiang Xu Zhongyu Lu Donglai Xu

Creep damage is one of the serious problems for the high temperature industries and computational approach (such as continuum damage mechanics) has been developed and used, complementary to the experimental approach, to assist safe operation. However, there are no ready creep damage constitutive equations to be used for predicting the lifetime for this type of alloy, particularly for low stress...

This study investigates the time-dependent long-term creep strain in a composite cylinder made of glass/vinylester with a unidirectional ply. The cylinder is subjected to an internal pressure and the boundary condition is free–free and acts as thermal insulation. The classical lamination theory (CLT) is used to derive the governing equations as a second-order equation to determine the radial, c...

2011
Matt Pharr Kejie Zhao Zhigang Suo Fan-Yi Ouyang Pilin Liu

When electric current flows in a solder bump, electromigration generates stress, but creep relaxes it. After some time, the bump develops a steady-state stress field. We present a theory to show that the two processes — electromigration and creep — set an intrinsic length. When the intrinsic length is large compared to the height of the bump, electromigration is fast relative to creep and the s...

Journal: :Physical review letters 2002
Dag Kristian Dysthe Yuri Podladchikov Francois Renard Jens Feder Bjørn Jamtveit

We present experimental evidence that pressure solution creep does not establish a steady-state interface microstructure as previously thought. Conversely, pressure solution controlled strain and the characteristic length scale of interface microstructures grow as the cubic root of time. Transient creep with the same scaling is known in metallurgy (Andrade creep). The apparent universal scaling...

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