Experimental component mode systhesis of structures with nonlinear joints

The accuracy of component mode synthesis is investigated experimentally for substructures coupled by non-ideal joints. The work is based upon a segmented experimental beam for which the free-interface frequency response matrices are measured for each segment. These measurements are used directly in component mode synthesis to predict the behavior of the assembled structure; the segments are then physically joined and the resulting frequency response of the superstructure is compared to the prediction. Rotational freeplay is then introduced into the connecting joint and the new superstructure frequency response is compared to the original linear CMS prediction. The level of accuracy to be expected in component mode synthesis is discussed in terms of the degree of nonlinearity in the joints, mode number and mode shapes.