the complete 3d nonlinear dynamic problem of extensible, flexible risers conveying fluid is considered. for describing the dynamics of the system, the newtonian derivation procedure is followed. the velocity field inside the pipe formulated using hydrostatic and bernoulli equations. the hydrodynamic effects of external fluids are taken into consideration through the nonlinear drag forces in var...

shape error due to elastic recovery of formed part in unloading known as springback, is one of the most important problems of tool design in sheet metal forming processes. many researches have been performed for proposing an efficient method to decrease or compensate springback error in sheet forming processes. these methods are usually based on iterative finite element algorithms. in this pape...

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...

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...