COMPARISON AND EXPERIMENTAL-VERIFICATION OF 2 TECHNIQUES FOR FRICTIONFORCE REPRESENTATION

The numerical estimate of the effectiveness of isolation systems with friction devices implies a correct solution of pertinent nonlinear equ ations of motion. Nowadays, the representation of the relationship fri ction force-displacement by an approximate rigid-perfectly plastic hys teretic model is the most widespread technique in the numerical calcul ations. The paper presents a comparison of this model with the recentl y proposed velocity model of the friction force. The results are verif ied with experimental data in order to ascertain how adequately these two methods describe that dynamic behaviour of systems with friction d evices. It is shown that, in the case of a hysteretic model, ''oscilla tions'' of relative velocity difference can appear at times when the s liding ceases. A correct condition is proposed in order to avoid this inaccuracy of the numerical solution. The results calculated by hyster etic and velocity models are similar and coincide well with experiment al data, when dealing with correct solutions. A conclusion is made, th at the velocity model, because of its simplicity, could be proposed fo r further development and implementation. Copyright (C) 1996 Elsevier Science Ltd