抄録
This paper presents large-scale structural eigen analyses using lumped mass matrix including negative components. The lumped mass matrix of some of the high order elements (for example 20-node hexahedral element) includes negative components. The authors have previously proposed a solution algorithm of eigen problems with non-positive definite lumped mass matrix. The algorithm was implemented on a parallel eigen analysis system. The accuracy of the eigenfrequency using 20-node hexahedral elements and lumped mass matrix was as high as that by the 20-node hexahedral elements and distributed mass matrix.
