Upper-Bound Plastic Collapse Analysis of Frameworks

摘要

An efficient and general, yet physically understandable, scheme was developed to obtain the collapse load factor of an arbitrary framed structure using an upper-bound approach. The most general mechanism of collapse is expressed by a linear combination of the elementary mechanisms, and the corresponding load multiplier lambda is obtained by equating work done by the applied loads to the plastic energy dissipated. The minimum of lambda is the required collapse load. Having examined the properties of lambda, a new matrix method to find its minimum is devised; a simple example illustrates the calculations. The method of minimization does not require non-negative variables as in previous schemes based on the Simplex method, and thus results in an algorithm which reduces computer storage and time requirements.