scholarly journals AVALIAÇÃO DO DESEMPENHO DO MÉTODO CPPM EM ANÁLISES ELASTOPLÁSTICAS

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria Paz Duque Gutiérrez ◽  
William Taylor Matias Silva

RESUMO: O método de projeção do ponto mais próximo (CPPM, closest point projection method) é amplamente utilizado quando se apresentam respostas não lineares no comportamento dos materiais. Este artigo destina-se ao detalhamento e formulação analítica do método e avaliar com exemplos simples seu desempenho utilizando distintas leis de endurecimento não lineares para definir a evolução das deformações plásticas. O método é implementado sob uma cinemática de deformações infinitesimais. É considerado que o material possui propriedades elásticas constantes. O critério de escoamento de von Mises é utilizado com uma regra associativa de fluxo para descrever o comportamento tensão-deformação do material. A principal contribuição deste trabalho é verificar a robustez do método e apresentar explicação completa da formulação analítica. ABSTRACT: The closest point projection method is widely used when nonlinear responses occur in the behavior of the materials. The aim of this work is detailing its analytical formulation with simple examples and evaluates the performance of the method using different nonlinear hardening laws to define the evolution of plastic deformation. The method is implemented under a kinematic of infinitesimal strains, it is considered a material with constant elastic properties, the von Mises yield criterion and an associative flow rule is used to describe the stress - strain behavior of the material. The main contribution of this work is to verify the robustness of the method and the complete explanation of the analytical formulation. RESUMEN. El método de proyección al punto más próximo (CPPM, closest point projection method) es ampliamente utilizado cuando se presentan respuestas no lineales en el comportamiento de los materiales. Se pretende con este trabajo detallar su formulación analítica y evaluar con ejemplos simples el desempeño del método utilizando diferentes leyes de endurecimiento no lineales para definir la evolución de las deformaciones plásticas. El método es implementado bajo una cinemática de deformaciones infinitesimales. Se considera un material con propiedades elásticas constantes, se emplea el criterio de fluencia de von Mises y una regla asociativa de flujo para describir el comportamiento tensión - deformación del material. La principal contribución de este trabajo es la verificación de la robustez del método y la explicación completa de la formulación analítica.

2020 ◽  
pp. 1-32 ◽  
Author(s):  
Elizaveta Vyacheslavovna Zipunova ◽  
Evgeny Borisovich Savenkov

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Nelli Aleksandrova

Displacement field calculations are necessary for many structural steel engineering problems such as cold expansion of holes, embedment of bolts and rivets, and installation and maintenance of external devices. To this end, rigorous closed form analytical displacement solution is obtained for structural steel open-hole plates with in-plane loading. The material of the model is considered to be elastic perfectly plastic obeying the von Mises yield criterion with its associated flow rule. On the basis of this solution, two simplified engineering formulae are proposed and carefully discussed for practical engineering purposes. Graphical representations of results show validity of each formula as compared with rigorous solution and other studies.


1968 ◽  
Vol 10 (2) ◽  
pp. 141-152 ◽  
Author(s):  
B. Fogg

A theory for the redrawing of cylindrical cups through conical dies is presented. In the absence of a pressure sleeve a zone of unconstrained drawing exists prior to the conical zone and the principle of minimum energy is used to establish the extent of the zone and the associated deformation and stresses. A linearization of the von Mises yield criterion for plane stress problems is adopted and use of the flow rule associated with this criterion allows the variation of thickness across an element to be taken into account in the solution of the stress equilibrium equation; the strains can also be determined without resorting to numerical integration. Because the deformation during redrawing takes place in a series of discrete steps, work-hardening can be conveniently included in the analysis. Bending and unbending contribute significantly to the process work and a more detailed examination of the mechanism is justified. The present theory allows the effects of friction, die angle and die intersection radius to be examined but the punch load/redrawing ratio relation has been considered for only one die profile and clearance. The results for the redrawing of 70/30 brass cups with and without interstage annealing are compared with experimental redrawing loads and whilst excellent agreement exists for the near-limiting redrawing ratios, the theory considerably over-estimates the punch loads at the smaller ratios. A possible reason for the difference is discussed.


2021 ◽  
Author(s):  
S. M. Kamal ◽  
Faruque Aziz

Abstract Rotational autofrettage is one of the recently proposed potential methods for eliminating the in-service yielding of thick-walled cylindrical pressure vessels. A few researchers have studied the feasibility of the process theoretically, and asserted certain advantages over the practicing hydraulic and swage autofrettage processes. In the literature, all theoretical analyses on the rotational autofrettage are based on the Tresca yield criterion and its associated flow rule, along with the assumption of different plane end conditions (plane strain and generalized plane strain). In this paper, an analysis of the rotational autofrettage of cylindrical vessel is attempted incorporating von Mises yield criterion. The plane strain condition is used for the analysis. A numerical shooting method is used to solve the governing differential equations providing the elastic-plastic stress distributions in the cylinder during loading. The present procedure is numerically experimented for a typical AH36 pressure vessel. It is found that the achievable level of the maximum stress pressure of the rotationally autofrettaged vessel is 74.46% higher than that of its non-autofrettaged counterpart for an overstrain level of 46.7%.


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