Accession Number : ADA180817

Title :   Divisor Structure of Finite Element Eigenproblems Arising From Negative and Zero Masses.

Descriptive Note : Technical summary rept.,

Corporate Author : WISCONSIN UNIV-MADISON MATHEMATICS RESEARCH CENTER

Personal Author(s) : Malkus,David S. ; Xianjun,Qiu

Report Date : FEB 1987

Pagination or Media Count : 7

Abstract : This document explains why and when the divisor structures of finite element eigenproblems is non-pathological even when negative and/or zero masses result from lumping schemes. The only case of concern is when the stiffness matrix is singular due to rigid body modes, as happens, for example, with single elements. It is found that there are no pathologies if the lumping scheme adequately reproduces the kinetic energy of rigid body motion. Keywords: Degree of precision; Mass matrix; Quadrature.

Descriptors :   *MATRICES(MATHEMATICS), KINETIC ENERGY, BODIES, MOTION, RIGIDITY, STIFFNESS, EIGENVECTORS, FINITE ELEMENT ANALYSIS, HEURISTIC METHODS

Subject Categories : Theoretical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE