임의 형상 멤브레인의 자유 진동 해석을 위한 NDIF법에서의 고유치 추출 기법 개선

A method to overcome the weakness of low-order eigenvalues not being extracted when the number of nodes is increased in the original NDIF method used in the eigenvalue analysis of arbitrarily shaped membranes has been proposed in a recent study. However, there is still the problem that the determinant curve of the system matrix that produces the eigenvalues has a discontinuity. In this study, an effective method to solve this discontinuity problem was proposed, and the validity and accuracy of the proposed method were confirmed through various example verifications. In the verification examples, the eigenvalues obtained from the proposed method were compared to those obtained from the original NDIF method, exact solution, and finite element method (ANSYS).