Sensitivity analysis of a class of nearly double bucklings

This paper is concerned with the imperfection-sensitivity of a class of nea rly double bucklings in doubly-Z(2)-symmetric elastic structures. Two types of imperfections are distinguished: the first is the imperfection of an au xiliary parameter, denoted by mu; the second is a geometric imperfection wi th amplitude tau. In the absence of geometric imperfections, such structure s display secondary buckling for values of mu > mu(c) near mu(c), the criti cal value of mu at which a double buckling load is created. Based on the sc aling technique and the implicit function theorem, the explicit asymptotic expressions of imperfection-sensitivity of the first unstable bifurcation p oint are established in terms of mu and tau. The derived formulas apply to finite-degree-of-freedom systems as well as continuous ones. As an example, the imperfection-sensitivity of a hinged-end elastic column with a central elastic support subjected to axial compression load is studied. (C) 1999 E lsevier Science Ltd. All rights reserved.