A GENERAL CAPABILITY OF DESIGN SENSITIVITY FOR FINITE ELEMENT SYSTEMS

Finite element analysis programs are generally used to analyze s tructural integrity. However, these programs do not normally have a ready made capability of evaluating the e ffects of changing the design (henceforth called sensitivity) on the structural behavior. Such a procedure is desirable for effective utilization of materials and resources and for t imely decisions on design modifications. A computerized procedure for design sensitivity has been developed using a general purpose finite element program EISIIEAL. The procedure is capable of predicting sensitivity of design (requirements namely stiffness, strength, frequency a nd mode shape) to changes in the design parameter.s. The term "design sensitivity" is used to indicate not only the computation of required derivatives but evaluations of appropriate d irection of moves for different design situations and determination of relative i mportance of design parameters f or improving design performance. The design variables can be a combination of the following parameters: sectional, materials, g eometrical and shape-properties pertaining to a generic f inite element model. The procedure is based on efficient derivative c omputations and post processing schemes that reduces the total time and user's involvement. The reliability and effectiveness of the method are examined by applying it t o t he design evaluation of two typical problems, a tapered beam and a composite wheel.