Premium
Imperfection Sensitivity or Insensitivity of Zero‐stiffness Postbuckling … that is the Question
Author(s) -
Jia Xin,
Hoefinger Gerhard,
Mang Herbert A.
Publication year - 2009
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200910094
Subject(s) - stiffness , zero (linguistics) , sensitivity (control systems) , path (computing) , imperfect , structural engineering , displacement (psychology) , control theory (sociology) , mathematics , degrees of freedom (physics and chemistry) , physics , engineering , computer science , thermodynamics , control (management) , psychology , philosophy , linguistics , electronic engineering , artificial intelligence , psychotherapist , programming language
Zero‐stiffness postbuckling of a structure is characterized by a secondary load‐displacement path along which the load remains constant. In sensitivity analysis of the (initial) postbuckling path it is usually considered as a borderline case between imperfection sensitivity and imperfection insensitivity. However, it is unclear whether zero‐stiffness postbuckling as such is imperfection sensitive or insensitive. In this paper, Koiter's initial postbuckling analysis is used as a tool for sensitivity analysis. Distinction between two kinds of imperfections is made on the basis of the behavior of the equilibrium path of the imperfect structure. New definitions of imperfection insensitivity of the postbuckling behavior are provided according to the classification of imperfections. A structure with two degrees of freedom with a zero‐stiffness postbuckling path is studied, considering four different imperfections. The results from this example show that zero‐stiffness postbuckling is a case of transition from imperfection sensitivity to imperfection insensitivity for imperfections of the first kind and that it is imperfection insensitive for imperfections of the second kind. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)