Shape and topology design sensitivity analysis and optimization of joining mechanism using doubly-curved shell

Methods for shape and topology design sensitivity analysis (DSA) and optimization of joining mechanisms, such as spot welding and adhesive bonding, using doubly-curved shell is presented to study the effect of location of joining mechanisms on structural performances. The material derivative concept of continuum mechanics and the adjoint variable method are employed to derive the shape and topology sensitivity expressions in domain integral form.; Shape design variables are the positions of spot welds and DSA identifies the critical spot-weld locations in the structure. Since spot welds are contained within the domain of the structure, the boundary of the domain is fixed and the design parameters are defined in the interior of the domain. Therefore, only the interior of the domain is allowed to move and the velocity is defined only for the interior of the domain. An optimization is performed to find the optimum spot-weld locations which will minimize or maintain the maximum displacement occurring in the structure.; The topology optimization based on density approach is carried out to study the effects of material distribution on structural performances. Topology design variables are the artificial densities and they are related mathematically to material properties such as Young's modulus. Topology DSA identifies the most critical layout of adhesive bonds and an optimization is performed to find the optimum distribution of these materials which will minimize or maintain the maximum displacement.; Numerical examples, by postprocessing NIKE3D FEA code, involving shape and topology optimization methodologies are given to demonstrate the validity of the methods presented in this research.