Optimal design of nonlinear shock isolation for large, locally nonlinear structural systems

Abstract

The method of Time Domain Structural Synthesis is reviewed and examples of linear structural modification and sub-structure coupling are presented. The general formulation for both linear and nonlinear syntheses are compared to highlight the similarities between the two and the difficulties experienced with the introduction of nonlinear elements. Examples of linear and nonlinear sub-structural coupling are presented to emphasize the similarity of the procedures used. Finally, a general approach for the optimal design of nonlinear shock isolation for large structural systems is developed. The repeated solution of arbitrarily large finite element models with localized nonlinear components is made possible through the use of a highly efficient nonlinear transient re-analysis procedure. The method has demonstrated order of magnitude decreases in compute time over traditional direct integration methods and is exact, regardless of the nature of the isolation. An example is included which demonstrates the procedure.