Optimization Techniques Applied to Mechanical Design

The present work deals with the application of optimization techniques to mechanical design. After an initial section devoted to a theoretical review of optimization algorithms in common use, the thesis consists of two parts. The first part is about the use of the adjoint method in the framework of aerodynamic shape optimization. After a theoretical review, the discrete adjoint method has been implemented in a research code based on the Discontinuous Galerkin (DG) method. This activity represents a new direction of development within the research group operating at University of Bergamo on DG methods for Computational Fluid Dynamics (CFD). Starting from the simple quasi-1D Euler equations, the implementation of the discrete adjoint method has been validated by comparing the values of computed adjoint variables with results of analytical solutions available in the literature. The method has then been applied to a shape optimization problem, using a gradient based algorithm with an inexact line search approach. The second part of the thesis deals with the application of optimization techniques to an industrial problem. This activity has been carried out at the R&D Centre of TenarisDalmine S.p.A., one of the largest seamless steel pipe producers in the world. This work focuses on the optimization of the thermal cycle of the mandrel of a longitudinal mandrel mill, with the objective of reducing the peak temperature of the mandrel during the rolling phase. The activity for this part of the thesis required the preliminary set up of a number of computational tools for the analysis of the physical aspects involved in the problem. Such tools have then been integrated in a comprehensive optimization approach driven by the optimization tools available in the Optimization Toolbox of the commercial software Matlab. The results of optimization are encouraging, showing the possibility of a considerable increase of the mandrel life cycle.