CHARACTERIZATION OF AUTOMOTIVE SHOCK-ABSORBERS USING RANDOM-EXCITATION

In a previous paper [see reference (4)], it was shown that the restori ng force surface (RFS) procedure provides a direct and clear method fo r characterizing the dynamic properties of automotive shock absorbers or dampers. The procedure was based on repetitive harmonic testing of the absorbers at fixed frequency but with varying amplitude. The curre nt paper describes how the surfaces can be obtained from tests using r andom excitation. The merits and demerits are discussed relative to th e harmonic test procedure. It is shown that the random excitation appr oach offers a useful alternative but produces force surfaces which are corrupted by small stochastic components; an explanation of the disto rtion is given in terms of the mathematical model proposed in the prev ious paper. The implications for identification of shock absorbers are discussed.