Hierarchical Domain Decomposition Method for Devices including Moving Bodies

This paper deals with three-dimensional non-steady eddy current analysis of a rotating machine as an example of a parallel finite element analysis including moving bodies. In general, high efficiency in parallel computing with a moving body is difficult to achieve. The hierarchical domain decomposition method (HDDM) is known as an efficient parallel finite element method. However, in cases that involve a moving body, the HDDM with static domain decomposition has not attained sufficient parallel efficiency. Moreover, the cost of dynamic domain decomposition is substantial. In this paper, we propose a new domain decomposition technique for the HDDM that enables us to achieve efficient scalability on massively parallel computers. Our method's parallel efficiency has been 93.3% on 96 computer nodes (1,536 cores) of the Oakleaf-FX supercomputer. Furthermore, an induction motor model with a seven million degrees of freedom mesh whose solution by conventional sequential computation requires more than a month has been successfully solved in approximately 1.60 hours using the proposed method.