نتایج جستجو برای: آزمون creep

تعداد نتایج: 130273  

2012
Calvin M. Stewart Ali P. Gordon

In the pressure vessel and piping and power industries, creep deformation has continued to be an important design consideration. Directionally solidified components have become commonplace. Creep deformation and damage is a common source of component failure. A considerable effort has gone into the study and development of constitutive models to account for such behavior. Creep deformation can ...

2006
H. K. Ann C. S. Kim Y. H. Shin I. K. Park

The effects of microstructures during creep on the ultrasonic attenuation have been investigated for Ni based superalloy (IN738LC). The cuboidal γ′ precipitates in the virgin material became coarsened preferentially in the direction perpendicular to the applied stress axis as creep time increased. The length of γ′ precipitates increased with creep time, while the width increased slightly. The i...

In this article, the problem of time-dependent stress redistribution of a piezomagnetic rotating thick-walled cylinder under an axisymmetric hygro-thermo-magneto-electro-mechanical loading is analyzed analytically for the condition of plane strain. Using the constitutive equations, a differential equation is found in which there are creep strains. Primarily, eliminating creep strains, an analyt...

2011
M. ZYCZKOWSKI

Optimal structural design of cylindrical shells under overall bending, torsion, tension and internal pressure in creep conditions is considered. The material is assumed to be governed by the Norton-Odqvist nonlinear steady creep law. Minimal weight of the shell is the design objective, radius and wall thickness are design variables, and the constraint refers to brittle creep rupture as describe...

2015
Dezheng Liu Qiang Xu Zhongyu Lu Donglai Xu

This paper reports the development of finite element software for creep damage analysis. Creep damage deformation and failure of high temperature structure is a serious problem for power generation and it is even more technically demanding under the current increasing demand of power and economic and sustainability pressure. This paper primarily consists of three parts: 1) the need and the just...

Journal: :Micromachines 2016
Huei Chu Weng

This study examines how thermal creep affects the mixed convection in a long horizontal parallel-plate microchannel under a pressure drop and a temperature rise. The analytical solutions of the fully developed thermal-flow fields and the corresponding characteristics are derived based on the Maxwell boundary conditions with thermal creep and presented for the physical properties of air at the s...

Creep age forming (CAF) process is a novel metal forming method with major benefits including improved mechanical properties and cost reduction for aviation industry applications. CAF happens due to creep phenomenon and stress-release during the artificial aging of heat-treatable  aluminum alloys. In this work, the creep age forming of 7075 Aluminum alloy at 120, 150 and 180 °C for 6, 24 and 48...

Journal: :journal of biomedical physics and engineering 0
h ashrafi department of mechanical engineering, k. n. toosi university of technology m shariyat department of mechanical engineering, k. n. toosi university of technology

introduction: nano-indentation has recently been employed as a powerful tool for determining the mechanical properties of biological tissues on nano and micro scales. a majority of soft biological tissues such as ligaments and tendons exhibit viscoelastic or time-dependent behaviors. the constitutive characterization of soft tissues is among very important subjects in clinical medicine and espe...

2016
Nicholas J. Martinez NICHOLAS J. MARTINEZ

Time dependent plastic deformation in metals can occur at high temperatures. Typically the creep test is conducted to characterize the deformation features; however, the conventional uniaxial power-law creep test may be impractical for small scale materials. Accordingly, instrumented indentation techniques are frequently employed. This study concerns the employment of instrumented indentation t...

2003
T. A. VENKATESH

The uniaxial compression-creep behavior of unidirectionally reinforced continuous-fiber composite materials was investigated for the case where both the matrix and the fiber underwent plastic deformation by creep. The creep behavior of NiAl composites reinforced with 5 to 20 vol pct tungsten fibers was characterized at 1025 8C. The NiAl-W composites exhibited a three-stage creep behavior, with ...

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