Extrusion is one of the widest used and the most basic processes of plastic forming, and the metal flow in extrusion is affected by many factors, such as friction, die shape, billet temperature and so on. Among these factors, friction is the key boundary condition to determine the property of the extruded products. In this paper research and measurements of velocity fields and impact of frictio...

One of the great challenges in the processing of materials using Equal Channel Angular Pressing (ECAP) is the high forming forces required to produce large shear deformation in the material. Researchers show that the friction forces between the die and the sample constitute a great part of the total forming forces. Recently, ultrasonic vibrations are successfully implemented into the ECAP proce...

We calculate the translational friction coefficient and the translational diffusion coefficient of a permeable cylinder moving in a sheet of fluid which is embedded on both sides in a fluid of much lower viscosity. The result, which is an asymptotic expression valid in the limit of small ratios of the viscosities, is derived by the method of matched asymptotic expansions.

one of the great challenges in the processing of materials using equal channel angular pressing (ecap) is the high forming forces required to produce large shear deformation in the material. researchers show that the friction forces between the die and the sample constitute a great part of the total forming forces. recently, ultrasonic vibrations are successfully implemented into the ecap proce...

This paper presents a comparison between a number of different failure prediction methods for superplastic forming processes. Attention is limited here to superplastic forming of Ti-6Al-4V at 927C. The failure prediction methods considered include the flow localisation factor approach, forming limit curves based on void growth models, such as the Rice and Tracey model and the Cocks and Ashby mo...

This paper presents a comparison between a number of different failure prediction methods forsuperplastic forming processes. Attention is limited here to superplastic forming of Ti-6Al-4V at 927C. Thefailure prediction methods considered include the flow localisation factor approach, forming limit curvesbased on void growth models, such as the Rice and Tracey model and the Cocks and...

In order to solve the problem that due to the unreasonable parameter Settings when use CAE analysis to produce the cars covering parts mould, such as sheet wrinkling, cracking, and more than an acceptable range of rebound. This article used CAE analysis software to find relatively reasonable parameters to achieve a reasonable analysis in the process of sheet metal forming defects and to put for...

Up to now a large number of models have been developed to measure or predict the damage in equipments. Some of these models have been implemented in ABAQUS software. To implement damage parameters in the software, it is necessary to perform complex and expensive practical tests. One of these damage models is Forming Limit Diagram (FLD).The purpose of this research is deriving required parameter...

The long-time/large-scale, small-friction asymptotic for the one dimensional Langevin equation with a periodic potential is studied in this paper. It is shown that the FreidlinWentzell and central limit theorem (homogenization) limits commute. We prove that, in the combined small friction, long-time/large-scale limit the particle position converges weakly to a Brownian motion with a singular di...