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Numerical Simulation Of Multi-field Coupling Problem Subjected To Impact Loads

Posted on:2015-05-02Degree:DoctorType:Dissertation
Country:ChinaCandidate:P GuoFull Text:PDF
GTID:1220330467486963Subject:Dynamics and Control
Abstract/Summary:PDF Full Text Request
The coupling problem subjected to impact loads, such as explosion, laser, crash, can be seen in a variety of engineering practices including aerospace, nuclear, laser technology and military etc. Multi-field coupling problems subjected to impact loads appear a number of complicated physical phenomenons in character of discontinuous and sharp gradient. In the recent years, numerical simulations for such problems have attracted a great deal of attentions from many international and domestic researchers. Due to the problems of accurate simulation method of coupling problems, numerical oscillations, data transmit, it still bring many uncerfianties for the solving of coupling problems. In this dissertation, the multi-field coupling problem subjected to impact loads is researched and a program system of solving the multi-field coupling problem is developed. The main work of this paper as bellow:(1) On the focus of characters of strong discontious and high gradient, the present paper develops a new version of modified time discontinuous Galerkin finite element method (MDGFEM) by introducing artificial damping term. Numerical examples illustrate good performance of the present method in eliminating spurious numerical oscillations of wave front and waveafter. Furthermore, the non-Fourier phenomenon with laser source is researched. The non-Fourier heat conducted problems in the semi-infinite body, thin film and biological tissues wtih various laser sources is simulated by using DGFEM. The simulated results show that the DGFEM proposes the good performance in eliminating spurious numerical oscillations and in providing more applicable in heat transfer problems with laser source.(2) By using the MDGFEM and the finite volume method based on the new geometric conservation law, an effective and accurate numerical simulation method for fluid-structure coupling interaction with impact load is developed. In order to reduce the impact of interpolation on accuracy, the gradient method which contained data transmit of pressure and heat flux has been proposed. In the interaction of discontinuous information, Bathe limiter is introduced in the radial basis function to capture the discontinuities and filter out the effects of spurious numerical oscillation. To show the accuracy and reliability of coupling methods, numerical examples such as piston problem, the airfoil aerodynamic flutter problem and aerodynamic heating problem are performed.(3) The MDGFEM for the solution of generalized thermo-elastic coupled problems is presented on the basis of well-known Lord-Shulman theory. To verify the validity of the method, Numerical examples were presented in this dissertation. The simulated results illustrate good performance of present method in eliminating spurious numerical oscillations and in capturing the discontinuous characteristic of wave propagation than classical time integration finite element method and the original DGFEM.(4) A multi-field program framework, which contained the performance of former single and multi-field problems with character of discontinuous and sharp gradient, is developed on the basis of design concept of modular. Three considered problems with complex configurations are studied, that is explosion, an elastic-plastic plate with areo impaction, solid rocket motor with grain defect subjected to shock wave. Based on successful applications of present numerical examples, the program system shows good prospects and good abilities for solving complex engineering applications.
Keywords/Search Tags:Multi-field coupling, Thermal mechanical coupling, fluid-structurecoupling, time discontinuous Galerkin finite element method, Arbitrary Lagrangian-Eulerianmethod, Numerical simulation
PDF Full Text Request
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