On the importance of Geometric Nonlinearity in Forced response Analysis of Structures with Friction Contact

The effect of ignoring geometric nonlinearity in a structure with friction contact on the forced response analysis is investigated. Forced response prediction of structures with friction non-linearity is usually performed by assuming geometrically linear structures. Although the dis-sipated energy via friction contact reduces the amplitude of vibrations and avoids large dis-placements, there are cases in which the structure still experiences geometric nonlinearity. In this study, the forced response analysis of a clamped beam with friction contact at its free end is computed by geometrically linear and nonlinear model. The analysis is performed in Fre-quency domain using Alternating Frequency-Time method. Nonlinear contact and elastic forces are obtained using a state of art contact element and nonlinear Finite Element formula-tion, respectively. The amplitude of vibration and hysteresis loop are compared to demon-strate the importance of geometric nonlinearity. The comparison of results shows considera-ble differences even in case of very small amplitude of vibration.

Keywords:

Forced response analysis , Geometric nonlinearity , Friction , Contact.