many procedures suggest for reduction of responses of riser to vortex induced vibrations (viv). natural frequencies of marine risers is an important parameter that can affect the responses of riser to viv. change of riser properties such as top tension and bending stiffness can alter natural frequencies. in this study effects of riser specifications on the responses and fatigue damage of marine...

rectangular waveguide (wr) is one of the earliest types of transmission lines. rectangular waveguide can be produced by hot extrusion process. in this paper, the hot extrusion process of cuzn5 rectangular waveguide was investigated by finite element method (fem). in addition, genetic algorithm method (ga) was used to optimize the die geometry and process conditions to achieve the lowest magnitu...

drying is an important operational step in pistachio processing. there is a decrease in moisture content of pistachio nuts from 56-57% (d.b.) to 5-6% during the drying process. drying conditions affect the quality of dried pistachio nuts, therefore, this calls for an accurate description of the drying trend in the process. in this study finite element formulation and solution of diffusive moist...

buckle folds are common traps for hydrocarbon in several contractional provinces. buckle folds form where stratified sequences rest a top salt or some other utterly weak rock as a decollemet zone in units with high competency contrasts by a compressive stress which acted along the length of the rock layers. an important parameter affecting buckle folding of a competent zone above a mobile decol...

in this paper, finding dynamic load carrying capacity (dlcc) of flexible link manipulators in point to-point motion was formulated as an optimal control problem. the finite element method was employed for modelling and deriving the dynamic equations of the system. the study employed indirect solution of optimal control for system motion planning. due to offline nature of the method, many diffic...

in this paper, an advanced formulation of the spectral finite element method (sfem) is presented and applied in order to carry out site response analysis of 2d topographic structures subjected to vertically propagating incident in-plane waves in time-domain. the accuracy, efficiency and applicability of the formulation are demonstrated by solving some wave scattering examples. a numerical param...

the purpose of this study is to compare the results of different probabilistic methods such as the perturbation method, stochastic finite element method (sfem) and monte carlo method. these methods were used to study the convergence of direct approach for slope stability analysis and are developed for a linear soil behavior. in this study, two dimensional random fields are used and both the fir...

statement of problem: impacts and accidents are considered as the main fac- tors in losing the teeth, so the analysis and design of the implants that they can be more resistant against impacts is very important. one of the important nu- merical methods having widespread application in various fields of engineering sciences is the finite element method. among its wide applications, the study of ...

a two-dimensional (2d) single particle model for the copolymerization of propylene-ethylene with heterogeneous ziegler-natta catalyst is developed. the model accounts for the effects of the initial shape of the catalyst and carck/ pore patterns on the copolymer composition, polymerization rate and the average molecular weight properties. the spherical and oblate ellipsoidal shapes of catalyst p...

background: the aim of this work was to study the feasibility of constructing a fast thorax model suitable for simulating lung motion due to respiration using only one ct dataset. materials and methods: for each of six patients with different thorax sizes, two sets of ct images were obtained in single-breath-hold inhale and exhale stages in the supine position. the ct images were then analyzed ...