Inertia Parameter Identification from Base Excitation Test Data

With the purpose to further investigate and improve a method for the identification of inertia parameters, tests with flexible test structures have been carried out. Reference data for the inertia parameters were obtained from a Finite Element model and from conventional weighing and pendulum measurements. For the realization of the base excitation a six-axis vibration simulator was utilized. The base forces were recorded with a special Force Measurement Device (FMD), and the base accelerations of the test structures were measured by accelerometers. Each of the 3 translational and 3 rotational axes of the multi-axial test facility was driven by a sine sweep signal with an appropriate base acceleration input. The application of the identification algorithm to the measured data showed that an acceptable identification of mass and mass moments of inertia is possible. However, a highly accurate identification of the center of gravity location could not be achieved. The results of the analyses are discussed and the advantages and limits of the present method are pointed out. Recommendations for the practical application and improved center of gravity identification are given

Parameter Identification and Validation of Large Order Finite Element Models for Industrial Type Structures

This lecture gives a brief overview of procedures for validating analytical models using experimental data including some exemplary results. The presentation is restricted to current procedures established by experience with large order industrial applications. The basic numerical techniques for updating the parameters of Finite Element (FE) models are described. Sources of modeling and test data uncertainties are addressed together with related requirements concerning the quality of the initial analytical model and the test data. Obstacles to ensure the prediction capability of the updated models to untested situations are discussed. The described applications include an automotive car body and a civil aircraft structure

Identification of Dynamics Modal Parameter for Car Chassis

This paper explores and investigates the dynamic characteristics of car chassis structure by using experimental modal analysis (EMA) method and modal testing. Dynamic characteristics are divided into three parameters include natural frequency, damping factor and mode shape. In this study, modal testing was performed on the car chassis including the impact hammer and shaker test. Data analyzer was used to convert the response signal from the sensor, which was in the time domain to frequency domain. Result obtained from both methods, is compared on each axis (X, Y and Z axis). However, small discrepancy was observed in terms of natural frequency, which is within the range of 5%. Based on the results, interpretation and comparison were made for both methods