Collapse of SDOF system to harmonic excitation

The investigation of the dynamic collapse behavior of structures during strong wind disturbances provides a rational foundation for estimating the safety factor of structures. In order to discuss the essential features of dynamic collapse behavior, the analyric and numerical studies are carried out on the dynamic behavior of single‐degree‐of‐freedom (SDOF) inelastic systems, also taking into consideration the effect of gravity under harmonic perturbation conditions with a mean static force. This model disturbance, which may be applied to wind disturbances, will be briefly called the harmonic excitation. The dynamic collapse condition of a system with respect to a harmonic excitation can be given by considering the elastic steady‐state response of the system. If an allowable displacement of a system is specified, the harmonic excitation which induces the system to collapse can be found. Inversely, if a harmonic excitation is specified, the tolerable displacement of the system can also be found.