We study the performance of the multigrid method applied to spectral element (SE) discretizations of the Poisson and Helmholtz equations. Smoothers based on finite element (FE) discretizations, overlapping Schwarz methods, and point-Jacobi are considered in conjunction with conjugate gradient and GMRES acceleration techniques. It is found that Schwarz methods based on restrictions of the origin...

This research introduces an advanced forging method to produce the door frame of the wind turbine tower. The advantage of the new forging method is the increase of raw material utilization ratio and the energy saving. In the conventional method, the door frame is hot forged with a hydraulic press and machined out lots of material because of the big difference between forging shape and final mac...

this paper presents a method for diagnosis of eccentricity fault in a switched-reluctance motor (srm) during offline and standstill modes. in this method, the fault signature is differential induced voltage (div) achieved by injecting diagnostic pulses to the motor windings. it will be demonstrated by means of results that there is a correlation between differential induced voltage and eccentri...

one of the bellows producing method is hydroforming process .whereas some factor of hydroforming process specially internal pressure affects on final characteristics produced bellows such as bursting, wrinkling and wall thickness distribution. in this paper the effect of internal pressure factor in final quality of produced bellows will be investigated. in simulation of process, abaqus/explicit...

nowadays, one of the main problems encountered in minimally invasive surgery and telesurgery is the detection of arteries in tissue. in this study, for the first time, tactile detection of an artery in tissue and distinguishing it from the tumor has been modeled by finite element method. in this modeling, three 2d models of tissue have been created: tissue, tissue including a tumor, and tissue ...

a new approach is proposed to model a crack in orthotropic composite media using the extended finite element method (xfem). the xfem uses the concept of partition of unity in addition to meshless basic idea of approximating a field variable by its values at a set of surrounding nodes. as a result, higher order approximations can be designed with the same total number of degrees of freedom. in t...

some numerical and experimental investigations are made on the performance of five different hyperelastic constitutive models (second order polynomial, yeoh, arruda-boyce, ogden and marlow) in tension and compressionmodes. first, the results of the tensile and compression tests on a rubber sample were used to determine the parameters of the models by curve fitting methods. next, by using an alg...

.hot metal gas forming of tubes can be used in various industries such as automotive and aerospace industries. in this process tube is formed at elevated temperatures, by using gas instead of fluid pressure. lower required pressure and low power are its advantages in comparison to hydroforming process. in this paper, a hot metal gas bulging process of an aluminum alloy tube has been investigate...

in this article, finite element method and ale formulation were used to numerically simulate impact of low-velocity specific projectiles with water surface. for the simulation, ls-dyna finite element code was used. material models which were used to express behavior of air and water included null material model. for the projectile, plastic-kinematics material model was applied. mie-gruneisen eq...