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Although the Efficient Global Optimization (EGO) algorithm has been widely used in multi-disciplinary optimization, it is still difficult to handle multiple constraint problems. In this study, to increase the accuracy of approximation, the Least Squares Support Vector Regression (LSSVR) is suggested to replace the kriging model for approximating both objective and constrained functions while the variances of these surrogate models are still obtained by kriging. To enhance the ability to search the feasible region, two criteria are suggested. First, a Maximize Probability of Feasibility (MPF) strategy to handle the infeasible initial sample points is suggested to generate feasible points. Second, a Multi-Constraint Parallel (MCP) criterion is suggested for multiple constraints handling, parallel computation and validation, respectively. To illustrate the efficiency of the suggested EGO-based method, several deterministic benchmarks are tested and the suggested methods demonstrate a superior performance compared with two other constrained algorithms. Finally, the suggested algorithm is successfully utilized to optimize the fiber path of variable-stiffness beam and lightweight B-pillar to demonstrate the performance for engineering applications. [ABSTRACT FROM AUTHOR]

Summary: A new equivalent circuit model (ECM) of a Li‐ion battery is developed in this study. The developed model is utilized to obtain the dynamic electrical response of the battery when it is deformed under external force. Compared with other models, this model is developed based on a modified Thevenin model, and the parameters of the developed model are relevant to state of charge, the battery surface temperature, and the deformation. In this study, to obtain the real electrical response of the battery when it deformed under external force, batteries that are compressed by different deformations from 0 to 5 mm are studied with pulse discharging tests. Then, the parameters of the circuit elements are identified by a differential evolution algorithm based on the data obtained from these tests. Moreover, the data from the pulse discharging tests of batteries compressed by 3.5, 4.25, and 4.5 mm and the data from the pulse charging tests of batteries compressed by 0 and 1 mm are used to verify the parameters. The results illustrate that the battery capacity should drop significantly when the battery is severely deformed, but the battery still can be charged and discharged. Most importantly, the discharging curves of these tested deformed batteries are similar to those of undeformed ones. Moreover, the developed new ECM can predict the dynamic electrical response of a deformed battery accurately. [ABSTRACT FROM AUTHOR]

A new thin-walled honeycomb structure for Li-ion battery packaging is designed and optimized in this study. Compared with other battery packaging structures, the designed honeycomb structure described here uses a grid to reinforce its strength. At the same time, the weight is reduced to improve the energy density of the entire package. Moreover, the new thin-walled structure can better protect the internal battery and improve the safety of an electric vehicle (EV). A space mapping (SM) algorithm is used to efficiently optimize the thin-walled honeycomb structure due to the expensive computational cost of each evaluation of a fine FE model. Compared with other SM algorithms, the coarse model of SM is based on a pseudo-plane-strain model. The result shows that the magnitude of stress and the distribution of stress are significantly improved compared with the initial structure. Moreover, the computational cost of optimization for the problem is also decreased significantly due to importing the coarse model. [ABSTRACT FROM AUTHOR]

This paper presents an alternative reanalysis algorithm based on the block matrix to address problems with local modifications. In this method, the modified stiffness can be classified as three parts: influenced region, stationary region and an interface region between them. The main computation cost concentrates on the influenced region by this specific blocked strategy. Compared with popular reanalysis methods, the proposed method can achieve an accurate response for large modification with lower computation cost. Several practical engineering problems are analyzed and the results are exactly as that performed by full analysis. [ABSTRACT FROM AUTHOR]