نتایج جستجو برای: strain softening behavior

تعداد نتایج: 829624  

2007
Athanasios E. Tzavaras

One of the most striking manifestations of instability in solid mechanics is the localiza-tion of shear strain into narrow bands during high speed, plastic deformations of metals. According to one theory, the formation of shear bands is attributed to eeective strain-softening response, which results at high strain rates as the net outcome of the innuence of thermal softening on the, normally, s...

To investigate the hot deformation behavior of 17-7 PH stainless steel, hot compression tests were carried out at the temperatures of 950, 1050 and 1150 oC and strain rates of 0.001 s-1 to 0.1 s-1. Accordingly, the hot working behavior was studied by the analyses of flow stress curves, work hardening rate versus stress curves, exponent- type constitutive equations and deformed microstructures. ...

Journal: :Acta Metallurgica Slovaca 2023

The steel alloy of the current study contains 0.3% carbon with different amounts Cr, and Mo, in addition to W. Single simulation hits were designed as isothermal passes for compressive hot deformation up 0.5 true strain. Each pass was carried out at temperatures, 1050, 950, 850 750 oC, strain rates 0.1 1.0 sec-1. A numerical computational model is used formulation flow behavior specified condit...

Laboratory hot torsion testing technique was carried out on one plain low carbon steel and two plain low carbon Nb and Nb-Ti micro alloyed steels to study the effects of chemical composition, micro alloying addition, on the dynamic softening and grain refinement of ferrite during warm deformation. Deformation schedule was conducted within two phase region (i.e. between Ar3-Ar1). The physical pr...

2011
Eva Gultova Lukas Horny Hynek Chlup Rudolf Zitny

This study compares the capability of two different mathematical forms of the so-called softening variable to describe strain-induced stress softening observed within cyclic uniaxial tension of the human thoracic aorta. Specifically, the softening variable, which serves as the stress reduction factor, was considered to be tangent hyperbolic-based and error function-based. The mechanical respons...

M. Bayatlou S.R. Sabbagh Yazdi,

A constitutive model based on two–dimensional unstructured Galerkin finite volume method (GFVM) is introduced and applied for analyzing nonlinear behavior of cracked concrete structures in equilibrium condition. The developed iterative solver treats concrete as an orthotropic nonlinear material and considers the softening and hardening behavior of concrete under compression and tension by using...

1999
Eric B. Becker

A phenomenological approach is used to represent the nonlinear viscoelastic behavior of solid propellants. A three dimensional nite strain viscoelastic model, modi ed by a strain softening function that accounts for damage e ects, is considered in the research. Some of the signi cant aspects of high-elongation propellants are incorporated into the constitutive model. The resulting stress-strain...

Journal: :international journal of civil engineering 0
r. mahin roosta assistant professor, engineering faculty, tarbiat modares university, tehran, iran a. alizadeh m.sc student, department of civil engineering, zanjan university,zanjan, iran

in the first impounding of rockfill dams, additional settlements occur in upstream side in saturated rockfills due to collapse phenomenon even high rainy seasons can cause additional deformation in the dumped rockfills. unfortunately these displacements are not taken into account in the conventional numerical models which are currently used to predict embankment dam behavior during impounding. ...

A. Shirvani and M. Farzin,

In this paper, shear localization due to strain softening in sidepressed cylinders, is inverstigated. Shear localization causes formation of macroscopic shear bands which can be obsserved in the metallographic cross-section. In this paper, for the first time a method is presented in which a simple two-slice model is used to study the formation of shear bands. The results obtained form this mode...

Journal: :Journal of applied physiology 2007
John E Speich Christopher Dosier Lindsey Borgsmiller Kevin Quintero Harry P Koo Paul H Ratz

Until the 1990s, the passive and active length-tension (L-T) relationships of smooth muscle were believed to be static, with a single passive force value and a single maximum active force value for each muscle length. However, recent studies have demonstrated that the active L-T relationship in airway smooth muscle is dynamic and adapts to length changes over a period of time. Furthermore, our ...

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