Accession Number : AD0920530

Title :   Stability Analysis of Linear and Nonlinear Dynamic Finite Element Method Programs.

Descriptive Note : Final rept. Oct 72-Jun 73,

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS

Personal Author(s) : Tracy, Fred T. ; Kirtland, Jesse L.

Report Date : JUN 1974

Pagination or Media Count : 68

Abstract : Linear and nonlinear dynamic finite element method (FEM) solution schemes are analyzed for stability in this report. Because of the diversity in techniques, representative methods are selected. For the linear case, a stability analysis in a way not heretofore done is performed for the extended Wilson linear acceleration, direct integration type scheme. This method is used in the program commonly known as FEAR. The effect of damping of the form C = alpha M + beta K is also studied. For the nonlinear case, the nonlinear version of FEAR (NOFEAR) is studied. The linear stability analysis techniques are applied to this solution scheme to determine the extent of usefulness of the linear techniques in the nonlinear realm. FEAR and NOFEAR are U. S. Army Engineer Waterways Experiment Station (WES) code names for two computer programs (written by Wilson and modified by WES) that use the direct integration techniques analyzed for stability in this report. The research reported is basic and theoretical in nature.

Descriptors :   (*COMPUTER PROGRAMS, DIFFERENCE EQUATIONS), (*STRUCTURES, BLAST), LINEAR PROGRAMMING, NONLINEAR PROGRAMMING, FINITE DIFFERENCE THEORY, EIGENVECTORS, ENGINEERING, INTEGRATION, ACCELERATION, STABILITY, ERRORS, MATRICES(MATHEMATICS).

Subject Categories : Theoretical Mathematics
      Computer Programming and Software
      Structural Engineering and Building Technology

Distribution Statement : APPROVED FOR PUBLIC RELEASE