Deformation of the material during cyclic expansion extrusion (CEE) is investigated using upper-bound theorem. The analytical approximation of forming loads agrees very well with the FEM results for different amounts of chamber diameter, friction factor and also for lower die angles. However, the difference between analytical and numerical solution increases at higher die angles which are expla...

recent developments in nanostructured products draw considerable attention to ultrafine grained materials. these materials are normally manufactured by different severe plastic deformation (spd) methods. in the present study, analytical models and finite element method (fem) are used to calculate strain imposed to a specimen that was deformed by equal channel angular pressing (ecap). in additio...

We report the first measurements of friction angles for a naturally formed gravel streambed. For a given test grain size placed on a bed surface, friction angles varied from 10" to over 100'; friction angle distributions can be expressed as a function of test grain size, median bed grain size, and bed sorting parameter. Friction angles decrease with increasing grain size relative to the median ...

In the present investigation, basic studies were conducted using an inclined pin-on-plate sliding tester to understand the influence of tilt angle and grinding marks direction of the plate on coefficient of friction and transfer layer formation during sliding against soft aluminium (Al) pin. 080 M40 steel plates were ground to attain different surface roughness with unidirectional grinding mark...

In the present investigation, two dimensional elastoplastic finite element analysis was conducted to assess the deformation characteristics of Al 1100 alloy during continuous confined strip shearing (C2S2) process. The results of simulations showed that the plastic strain distribution across the deformed sample is non-uniform irrespective of the amount of friction and C2S2 die angle. The most u...

We analyze two- and three-link planar snakelike locomotion and optimize the motion for efficiency. The locomoting system consists of two or three identical inextensible links connected via hinge joints, and the angles between the links are actuated as prescribed periodic functions of time. An essential feature of snake locomotion is frictional anisotropy: The forward, backward, and transverse c...

Objectives: One of the applications of ergonomics disciplinary is designing driver workstation compatible to users’ characteristics. The aim of this study was evaluation of interior design of Shoka vehicle with respect to the accommodation for Iranian population and proposing suggestions for customizing design of the vehicle. Methods: This study was a descriptive-analytical study conducted a...