Papers by Keyword: Softening Behavior

Abstract: In this paper, firstly we utilize the elastic model, which provides the simplest representation of material behavior in civil engineering. This model is valid for homogeneous, isotropic, continuous materials that exhibit linear stress-strain behavior with no hysteresis on unloading. The elastic models include both isotropic and anisotropic elastic models. Then the Mohr-Coulomb model is used which can represent shear failure in soils and rocks in civil engineering and geotechnical engineering. After that, the strain- softening model is founded, which allows representation of nonlinear material softening and hardening behavior based on prescribed variations of the Mohr-Coulomb model properties (cohesion, friction, dilation, tensile strength) as functions of the deviatoric plastic strain. Finally, a case study is done for the stratified rock mass, the elastic modulus of the rock sample for different surrounding compressive are obtained, to exhibit the anisotropy characteristic of this type of rock material

Abstract: Softening behavior of deformed austenite zone of E36 ship plate in hot continuous rolling process was studied with double passes compression experiments, including cases in different deformation temperature and time span. Analyzing the influence of different factors on the softening ratio of static recrystallization. The results show that deformation temperature is the main factor to influence the recrystallization. When the deformation temperature being achieved, static recystallization ratio increases step by step with time span extending. The best time span was got and the softening ratio curve was verified through metallographic analysis, and the activation energy was obtained. Dynamic model of static recystallization was built at the end.

Abstract: Finish rolling in the two-phase region may offer new possibilities for improving the properties of the FeSi steels with phase transformation. Therefore a deeper understanding of the effects by hot rolling in the two phase region or mixed rolling: multistep hot rolling in the two phase region and in the ferrite region on the evolution of the microstructure is desirable. In this paper we will present the results of our experimental studies on the effect of hot rolling in the intercritical state on the hardening and softening in the ferrite state. It will be demonstrated that depending on the process conditions at hot rolling the austenite ferrite transformation affects the stress strain behaviour in the ferrite state at multistep hot rolling remarkable.

Abstract: In the study, thermal efficiency in MIG welding of aluminum alloy with longitudinal magnetic field was analyzed, as well as softening behavior of heat-affected zone (HAZ) and base metal were investigated. The results showed that welding current decreased and resultingly total heat input reduced as the exciting current increased, meanwhile arc thermal efficiency increased and melting efficiency decreased. As a result of action of the magnetic field, the trend of grain growth of HAZ slowed down and the influence on base metal of heat input decreased. When the exciting current was 20A, microhardness of HAZ and base metal improved evidently. However, as the exciting current continued to increase, the effect of magnetic field on softening behavior did not change significantly.

Abstract: In this paper, a novel constitutive model of concrete has been proposed by introducing a new parameter, namely, cracking Poisson’s ratio (νcr), to account for the effect of localization due to cracking. By fitting the curve between the dimensionless strain (ε/εpr) and cracking Poisson’s ratio (νcr), νcr can be expressed as an 3rd order polynomial function of dimensionless longitudinal strain (ε/εpr). The constitutive model for the softening regime can then be proposed with the parameters of dimensionless strain and cracking Poisson’s ratio. Finally, Validity of the proposed model is verified by the test results of cylinder specimens of C30.