American Institute of Aeronautics and Astronautics 1 Topology Optimization of Passive Shock Isolator Considering Prescribed Load-Displacement Functions Junghwan Kook 1 and Semyung Wang 2 Department of Mechatronics, Gwangju Institute of Science and Technology, Gwangju, 500-712, Korea This paper describes the use of topology optimization as a tool for the design of shock isolator, which is based on cone-type disc spring for prescribed load-displacement functions. The objective function evaluates load-displacement relationship based on the prescribed softening load-displacement function, which improve shock isolation capability. The geometrically nonlinear behavior of the shock isolator is modeled using total Lagrangian finite element formulation. The resulting nonlinear system is solved using a Newton- Raphson iterative scheme. The sensitivity in topology optimization, adjoint variable method is employed. Several examples are presented to demonstrate the capability and effectiveness of the proposed method. Nomenclature F s = force of spring element k = initial slope of the force-deflection curve d = displacement corresponding the spring force near the asymptote with initial stiffness k ߜ= deflection of spring element ݑሶ m = effect of a velocity step of magnitude ݔሷ m = maximum transmitted acceleration ߜ m = maximum isolator deflection K = stiffness matrix t K = tangent stiffness matrix U = displacement vector R = applied load vector t = configurations time ݐ∆= time increment F = nodal point force vector P = residual vector out-of-balance load vector ߖ= performance index ߟ= design variables, in topology optimization the relative density p = penalization power E 0 = Young’s modulus of the original material ߣ= adjoint variable, adjoint load ߚ= volume fraction V 0 = initial volume I. Introduction hock isolators are developed to protect equipments against severe unexpected shock excitations. The common shock isolators are characterized by two main performances; the natural frequencies and the load-bearing capability of the system. These two contradict each other because of their own characteristics; if the natural frequency is lowered to reduce the transmitted shock force, the load-bearing capacity, which is affected by the stiffness of the system, is reduced. Until now, the studies about the theoretical maximum isolation capability of 1 Ph.D Candidate, Mechatronics ,jhkook@gist.ac.kr, AIAA Member. 2 Professor, Mechatronics ,smwang@gist.ac.kr, Senior Member of AIAA. S 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference <br>17th 4 - 7 May 2009, Palm Springs, California AIAA 2009-2525 Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.