Reanalysis of trusses using modified initial designs

This paper presents a solution procedure for reanalysis using a mixed exact-approximate approach. The procedure, which is based on the reduced basis method, uses an efficient exact reanalysis method to handle a limited number of dominant member area and topological changes. A modified initial design (MID), associated with which is a recalculated inverse of the modified stiffness matrix, is the starting point for the approximate technique. Local geometrical changes may be accounted for within the modified initial design. An approximate technique is then used to handle the rest of the changes. This solution procedure significantly improves the accuracy of the approximation and conveniently accommodates geometrical and topological changes which occur in layout optimization of structures. The main purpose of this paper is to exploit, for a better balance between efficiency and accuracy, the advantages of the exact approach for reanalysis which is efficient for a small number of changes and the approximate approach for reanalysis which is efficient for a large number of changes of small magnitude.