In this paper the dynamic behaviour of a multi degree of freedom beam model of a solar array structure is investigated both experimentally and numerically. The beam is supported by one nonlinear element, a so-called snubber. This snubber can only take compressive forces. Two types of excitation are applied and compared: sine sweep excitation (with different sweep rates and directions) and steady-state excitation. Emphasis lies on the investigation of the dynamic behaviour of the system under prestress, which implies softening behaviour at the time when snubber and beam loose contact. The system displays rich nonlinear dynamic behaviour: multiple solutions (hysteresis loop), superharmonic resonances and subharmonic, quasi-periodic and chaotic solutions. Good correspondence between experimental and numerical results has been found.