Nonlinear System Identification with Applications to Durability Testing of Ground Vehicle Components
Presently in ground vehicle industries, conducting durability tests is an essential step to predict the life of full vehicle, subsystem and component designs. The procedure of durability testing includes measuring the data in the test track, generating the accelerated loading profiles and implementing it by using the base excited shaker table. The problem associated with the implementation is the output loading profiles measured from the shaker table deviates from the desired input loading profiles. The engineering problem associated with the implementation is due to the unknown dynamics of the test structure, such as, nonlinear stiffness and damping. A new approach for the nonlinear system identification of continuous lightly damped system from the experimental data is presented. The new approach is based on the theory of force reconstruction, base excitation and nonlinear system identification. The methodology is verified by using the simulation example and is demonstrated by using the cantilever beam as an example. An experimental setup is designed, fabricated and installed in order to demonstrate the proposed methodology. The experimental setup is similar to that of industrial settings but with lower power range. Several experimental case studies are carried out to demonstrate the proposed methodology. The results from the experiments are the identification of viscous damping coefficient dependent upon the displacement amplitudes and the cubic stiffness nonlinearity.