Efficient Simulation of Structural Dynamic Systems with Discrete Nonlinearities

Authors: Kevin M. Roughen (M4), Jinhua Huang (M4), Daniel C. Hammerand (M40, Daniel S. Stuewe (M4), Shawn R. Hertz(USN)

Conference: AIAA 52nd Structures, Structural Dynamics and Materials Conference (2011)

Abstract: Dynamic loading environments often involve complex loading and boundary conditions. For the case of externally mounted aircraft stores, qualification testing involves simulating this environment with relatively simple test fixtures and load application shakers. Simulation using Finite Element Analysis (FEA) is used to ensure that the test conditions are representative of the service environment. In this development, a method for efficiently simulating test and service conditions is presented. The component mode synthesis method is used to significantly reduce the computational requirements of solving nonlinear store vibration problems while retaining a straightforward model structure at user specified boundary locations. While the component mode synthesis method provides an efficient coordinate transformation, the physical meaning of the degrees of freedom at the boundary are preserved. Nonlinear stiffness functions at the boundary degrees of freedom are added after the linear potion of the model has been reduced. The resulting set of nonlinear equations is integrated in time. Accuracy and computational expense are evaluated through comparison to full-order nonlinear solutions from existing commercial software