Experimental identification of nonlinearity in bolted beam structure using force-controlled stepped-sine testing and response-controlled stepped-sine testing

Identifying nonlinearities in structural dynamic is important for complex and advanced engineering structures, particularly slender structures with bolted joints which is very common in various engineering fields such as aerospace, automotive and civil constructions. Nonlinear phenomena such as unstable branches, sub- and superharmonic often occur in these structures, which linear modal analysis is invalid for the identification of these nonlinear phenomena. These nonlinearities play an important role in affecting the behaviour and stability under various dynamic loads.