Parallelized multiobjective efficient global optimization algorithm and its applications
In engineering practice, most optimization problems have multiple objectives, which are usually in a form of expensive black box functions. The multiobjective efficient global optimization (MOEGO) algorithms have been proposed recently to sequentially sample the design space, aiming to seek for optima with a minimum number of sampling points. With the advance in computing resources, it is wise to make optimization parallelizable to shorten the total design cycle further. In this study, two different parallelized multiobjective efficient global optimization algorithms were proposed on the basis of the Kriging modeling technique. With use of the multiobjective expectation improvement, the proposed algorithm is able to balance local exploitation and global exploration. To implement parallel computing, the "Kriging Believer" and "multiple good local optima" strategies were adopted here to develop new sample infill criteria for multiobjective optimization problems. The proposed algorithms were applied to five mathematical benchmark examples first, which demonstrated faster convergence and better accuracy with more uniform distribution of Pareto points, in comparison with the two other conventional algorithms. The best performed "Kriging Believer" strategy approach was then applied to two more sophisticated real life engineering case studies on the tailor rolled blank (TRB) structures for crashworthiness design. After optimization, the TRB hat shaped tube achieved a 3% increase in energy absorption and a 10.7% reduction in mass, and the TRB B pillar attained a 10.1% reduction in mass and a 12.8% decrease in intrusion, simultaneously. These benchmark and engineering examples demonstrated that the proposed methods are fairly promising for being an effective tool for a range of design problems.