Optimization of hole reinforcements by doublers

Abstract

For various technical reasons, cutouts such as holes in thin-walled structures are inevitable and are of significant technical relevance. Unfortunately holes lead to an undesired stress concentration at the hole vicinity and a reduced strength of the structure. Therefore in practice a local reinforcement is usually applied around the hole. The increasing requirements for modern structures in terms of low weight and high strength lead to the question of an optimal reinforcement design. The present paper addresses the well-approved techniques of mathematical structural optimization to determine the aforementioned optimal design of the reinforcement. Thus it is necessary to set up an optimization model, as well as an appropriate structural model, to obtain the structural response (displacements, stresses ...). In this work, the finite element method has been applied for the structural analysis. The optimization procedure described has been utilized for a number of different reinforcement alternatives under various load cases. The numerical procedure implemented works with good reliability and efficiency and gives optimal reinforcement designs that are very useful for the direct engineering application. The results obtained illustrate the necessity and usefulness of the applied optimization procedure.