a two-dimensional single particle finite element model was used to examine the effects of particle fragmental pattern on the average molecular weights, polymerization rate and particle overheating in heterogeneous ziegler-natta olefin polymerization. a two-site catalyst kinetic mechanism was employed together with a dynamic two-dimensional molecular species in diffusion-reaction equation. the i...

this research work is devoted to experimental and theoretical evaluations of a hybrid constitutive model which was designed to simulate the mechanical behavior of a tread rubber compound. the model is a combination of yeoh hyperelastic model with a strain-rate hysteresis model developed by bergstrom and boyce. the parameters of the yeoh model were calibrated from experimental data of the astm d...

afinite element model of a bias truck tire under static vertical load using a global/local technique is designed in two parts. in the first part a previously created model for radial tires is developed to take the constructional variables of bias tires into account. it is shown that the technique can successfully be used for bias tires. the main challenge here is the selection of the initial la...

electrostatic potential as well as the local volume charge density are computed for a macromolecule by solving the poisson-boltzmann equation (pbe) using the finite element method (fem). as a verification, our numerical results for a one dimensional pbe, which corresponds to an infinite-length macromolecule, are compared with the existing analytical solution and good agreement is found. as a ma...

stability of foundations near slopes is one of the important and complicated problems in geotechnical engineering, which has been investigated by various methods such as limit equilibrium, limit analysis, slip-line, finite element and discrete element. the complexity of this problem is resulted from the combination of two probable failures: foundation failure and overall slope failure. the curr...

superplastic materials show a very high ductility. this is due to both peculiar process conditions and material intrinsic characteristics. however, a number of superplastic materials are subjected to cavitation during superplastic deformation. evidently, extensive cavitation imposes significant limitations on their commercial application. the deformation and failure of superplastic sheet metals...

Flexible rotors are characterized by inherent uncertainties affecting the parameters that influence the dynamic responses of the system. In this context, the handling of variability in rotor dynamics is a natural and necessary extension of the modeling capability of the existing techniques of deterministic analysis. Among the various methods used to model uncertainties, the stochastic finite el...

A finite element method for stochastic dynamic programming is developed. The computational method is valid for a general class of optimal control problems that are nonlinear and perturbed by general Markov noise in continuous time, including jump Poisson noise. Stability and convergence of the method are verified and its storage utilization efficiency over the traditional finite difference meth...

this paper presents an overview of model updating and particularly its application for updating of frame model. in this article a mathematical model of the frame was produced with finite element method. the frame was subjected to hammer modal testing. then the results of the modal testing were compared with those predicted with the model. this comparison revealed discrepancies between these two...

The project focused on the development, analysis, implementation, and application of efficient and high-order accurate methods formulti-scale and stochastic problems. Research focused on three topics: (1) High order weighted essentially non-oscillatory finite difference and finite volume schemes,discontinuous Galerkin finite elementmethod, and related methods, for solving comput...