This text deals with the irreversible deformation of structural elements composed of ductile materials. It is concerned with the mechanics of static and dynamic deformation processes that result from large loads. The aim is to develop analytical models that represent more complex material properties and structural characteristics. The behaviour of these systems is compared with experimental measurements of structural response. Methods of incorporating elastic-plastic deformations and interaction yield surfaces into transient structural dynamics are presented for the first time. These are used to calculate deformations for curved and non-uniform structural members. First published in 1993, this text has established itself for those teaching analytical methods of non-linear structural dynamics. This softcover edition will make an authoritative text more widely available to a variety of students.