Kim D., Han J.

Most practical engineering structures are complicated and may have some nonlinearities such as preload, free-play, asymmetric bilinear stiffness, hysterisis, coulomb damping, and sliding surfaces, etc. These nonlinearities are impossible to be completely eliminated, and they exert significant effects on the static and dynamic characteristics. Therefore, it is necessary to establish an accurate structural dynamic model to predict or control the nonlinear dynamic systems. In the present study, a structural coupling method is developed to be utilized in the dynamic analysis of nonlinear structures with concentrated nonlinear hinge joints or sliding lines. For simplicity of the problem, the nonlinear structures composed of two substructures and the nonlinearities are considered. Component Mode Synthesis method, which is a structural coupling method permitting the representation of a relatively complex structure by a reduced number of degrees of freedoms, is expanded to couple the substructures and the nonlinear models so that iterative problems such as flutter can be efficiently analyzed with a reasonable cost and time. In order to verify the expanded coupling method, the structural model of a deployable missile control fin model, which consists of upper and lower wings and a nonlinear hinge, is established by using the coupling method. The dynamic results are compared with experimental data and show in good agreements. Secondly, the coupling method is applied to a pantograph tilting structure which consists of a pantograph, sledge and base frames. There is structural nonlinearity of sliding lines between the base frame and the sledge which is restricted to follow guide lines on the base frame. The structural model is verified with dynamic results and it shows reasonable agreements. The dynamic characteristics of the nonlinear structural models show that the coupling method is adequate for the structural nonlinear analyses such as the nonlinear hinge and sliding mode condition.