scholarly journals Análise Não Linear Geométrica de Treliças Espaciais Associada às Técnicas de Continuação de Comprimento de Arco/ Geometric Nonlinear Analysis of Space Trusses Associated with Arc-Length Path-Following Techniques

2021 ◽  
Vol 5 (5) ◽  
pp. 2029-2051
Author(s):  
Lucas Dezotti Tolentino ◽  
Luiz Antonio Farani de Souza ◽  
Romel Dias Vanderlei ◽  
Leandro Vanalli

Neste artigo, são desenvolvidos algoritmos baseados no método de Newton-Raphson associado às técnicas de Comprimento de Arco Linear, Comprimento de Arco Esférico e Comprimento de Arco Cilíndrico, com o objetivo de validar a equação proposta para o coeficiente de escala. As análises não lineares são efetuadas por meio do método Corrotacional dos Elementos Finitos considerando problemas de treliças espaciais com não linearidade geométrica, cujas trajetórias de equilíbrio apresentam pontos limites de força e deslocamento. Os resultados numéricos versam sobre o tempo de processamento, números totais de passos de carga e iterações acumuladas até a convergência para a solução, além do número médio de iterações por passo de carga. As técnicas de continuação são comparadas e os resultados evidenciam a eficácia do Comprimento de Arco Linear, decorrente da simplicidade da formulação e boa concordância com os resultados observados na literatura, além da não restrição quanto à aplicação em problemas de maior complexidade.

2017 ◽  
Vol 14 (5) ◽  
pp. 381-405 ◽  
Author(s):  
Mohammad Rezaiee-Pajand ◽  
Hossein Estiri

Purpose Numerical experiences reveal that the performances of the dynamic relaxation (DR) method are related to the structural types. This paper is devoted to compare the DR schemes for geometric nonlinear analysis of shells. To achieve this task, 12 famous approaches are briefly introduced. The differences among these schemes are between the estimation of the time step, the mass and the damping matrices. In this study, several benchmark structures are analyzed by using these 12 techniques. Based on the number of iterations and the analysis duration, their performances are graded. Numerical findings reveal the high efficiency of the kinetic DR (kdDR) approach and Underwood’s strategy. Design/methodology/approach Up to now, the performances of various DR algorithms for geometric nonlinear analysis of thin shells have not been investigated. In this paper, 12 famous DR methods have been used for solving these structures. It should be noted that the difference between these approaches is in the estimation of the fictitious parameters. The aforementioned techniques are used to solve several numerical samples. Then, the performances of all schemes are graded based on the number of iterations and the analysis duration. Findings The final ranking of each strategy will be obtained after studying all numerical examples. It is worth emphasizing that the number of iterations and that of convergence points of the arc length algorithms are dependent on the value of the initial arc length. In other words, a slight change in the magnitude of the arc length may lead to the wrong responses. Contrary to this behavior, the analyzer’s role in the dynamic relaxation techniques is considerably less than the arc length method. In the DR strategies when the answer approaches the limit points, the iteration number increases automatically. As a result, this algorithm can be used to analyze the structures with complex equilibrium paths. Research limitations/implications Numerical experiences reveal that the DR method performances are related to the structural types. This paper is devoted to compare the DR schemes for geometric nonlinear analysis of shells. Practical implications Geometric nonlinear analysis of shells is a sophisticated procedure. Consequently, extensive research studies have been conducted to analyze the shells efficiently. The most important characteristic of these structures is their high resistance against pressure. This study demonstrates the performances of various DR methods in solving shell structures. Originality/value Up to now, the performances of various DR algorithms for geometric nonlinear analysis of thin shells are not investigated.


2021 ◽  
Vol 42 (1) ◽  
pp. 63
Author(s):  
Luiz Antonio Farani de Souza ◽  
Emerson Vitor Castelani ◽  
Wesley Vagner Inês Shirabayashi

In this paper we adapt the Newton-Raphson and Potra-Pták algorithms by combining them with the modified Newton-Raphson method by inserting a condition. Problems of systems of sparse nonlinear equations are solved the algorithms implemented in Matlab® environment. In addition, the methods are adapted and applied to space trusses problems with geometric nonlinear behavior. Structures are discretized by the Finite Element Positional Method, and nonlinear responses are obtained in an incremental and iterative process using the Linear Arc-Length path-following technique. For the studied problems, the proposed algorithms had good computational performance reaching the solution with shorter processing time and fewer iterations until convergence to a given tolerance, when compared to the standard algorithms of the Newton-Raphson and Potra-Pták methods.


Sign in / Sign up

Export Citation Format

Share Document