A conjugate modal force strategy for instability analysis of thin-walled structures: an unconstrained vector positional finite element approach

• Autor(a) principal: Soares,Henrique Barbosa
• Data de Publicação: 2021
• Outros Autores: Paccola,Rodrigo Ribeiro, Coda,Humberto Breves
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Latin American journal of solids and structures (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-78252021000200502
• topic: Conjugate Modal Force; Instability Analysis; Geometrically Exact FEM; Positional FEM

Abstract The importance of knowing critical loads and post-critical behavior of thin-walled structures motivates the development of several scientific and practical studies. Most references are concerned with stability analysis for small displacements (first order approach), or with second order stability analyzes, a less precise geometric nonlinear strategy. However, very flexible structures or ones that present small loss of stiffness after the first critical load need more careful analysis. Here we present a shell numerical formulation capable of carrying out stability analysis of thin-walled structures developing large displacements. This formulation uses generalized unconstrained vectors as nodal parameters instead of rotations. To make possible a complete stability analysis using unconstrained vectors, we present an original strategy that imposes a Conjugate Modal Force at the vicinity of critical points, allowing an accurate choice of post-critical paths. Non-conservative forces are also considered and results are compared with literature benchmarks, demonstrating the accuracy and capacity of the proposed formulation.