EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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3 resultados
Resultados da Pesquisa
Item Comparison between recent implicit time integration methods with frequency dissipation for nonlinear structural applications.(2022) Fernandes, William Luiz; Barbosa, Gustavo Botelho; Greco, Marcelo; Silveira, Ricardo Azoubel da MotaThe present paper aims to test recent (Truly self-starting two sub-step method and three-parameter singlestep implicit method) and classical (Generalized-α, HHT-α, and WBZ-α methods) time integration methods using the geometrically nonlinear Positional Finite Element Method (PFEM). The numerical formulation is based on the total Lagrangian approach and uses the Hessian matrix to obtain the response. The mixed hardening inelastic model applied to PFEM is also presented. Two examples validate the time integration algorithms and the inelastic model. In the first example, the mixed hardening inelastic model is compared with the the bilinear stress-strain model and the elastic-perfectly plastic hinge model, and aspects such as amplitude decay and period elongation are discussed. In the second example, the implemented algorithms are verified in a severe geometrically nonlinear example, considering the influence of numerical dissipation, time interval, and the number of elements in the response. Results show the relevance of numerical damping for numerical stabilization and the good performance of the Generalized-α algorithm.Item Multi-objective topology optimization using the Boundary Element Method.(2019) Simonetti, Hélio Luiz; Almeida, Valério da Silva; Neves, Francisco de Assis das; Greco, MarceloThis article aims to explore the application of an evolutionary optimization technique for multi-objective optimization problems using as criteria the minimization of von Mises maximum stress and minimization of the maximum growth of internal structural strain energy. To evaluate the overall effect on the optimal design configuration, due to the removal of inefficient material from the structure by using these two optimization criteria, a goal weighting scheme is adopted, whereby the weight factors emphasize and balance the stress and strain energy criteria. Also considered in this study was the method of the exponentially weighted criterion for multi-objective optimization and the Pareto optimal concept. Thus, a contribution is made to the study of these two methods in the structural optimization procedure using a linear analysis by the Boundary Element Method. Four examples are presented to demonstrate the ability of the proposed method to solve structural design problems using multi-objective optimization.Item Topology optimization applied to 2D elasticity problems considering the geometrical nonlinearity.(2015) Fernandes, Walliston dos Santos; Almeida, Valério da Silva; Neves, Francisco de Assis das; Greco, MarceloTopological Optimization (TO) of structures in plane stress state with material elastic-linear behavior, buttaking into consideration the geometrical nonlinearities, was performed and the results are presented herein. For this process, an evolutionary heuristic formulation denominated SESO (Smoothing Evolutionary Structural Optimization) associated with a finite element method was applied. SESO is a variant of the classic evolutionary structural optimization (ESO) method, where a smoothing process is applied in the ‘‘hard-kill’’ process of element removal – that is, their removal is done smoothly, reducing the values of the constitutive matrix of the element as if it were in the process of damage. It has been demonstrated that this non-linear geometric phenomenon clearly influences the final optimized topology when compared to an optimum configuration obtained with the equilibrium equations written at an undeformed position. Some numerical examples from literature are presented in order to show the differences in the final optimal topology when linear and non-linear analyses are used, allowing the verification of the importance of correctly analyzing the final optimum topology and as such, demonstrate the advantages of SESO as a structural optimization method.