Component Modal Tests to Identify the Dynamic Characteristics of Large Structures - Effect of Modeling Errors

摘要

This paper describes a new test method to obtain the dynamic characteristics of large structures such as satellite antennas and solar paddles. It has become increasingly difficult to perform modal tests for large deployed antennas and solar paddles because they are not strong enough to withstand the force due to gravity. Component modal tests are effective to predict the dynamic characteristics of these structures. In this method, the effect of untested components is considered as additional mass and stiffness attached to a tested component. Modal tests are performed for different tested components, and we consider identical frequencies obtained by component modal tests as frequencies of structures. Additional mass and stiffness, attached to an arbitrary degree of freedom, are found by reducing mass and stiffness matrices of untested components. Therefore, when finite element models have modeling errors, additional mass and stiffness affect significantly on test results. This paper shows the effect of modeling errors on component test results.