A major concern of the design engineer is how a structure will behave under abnormal but foreseeable loadings imposed when an accident occurs. Although such questions can be answered solely by model testing and experimentation the costs incurred are inevitably prohibitive. This paper demonstrates the power of the finite element method in modelling the response of structures to abnormal loads and showing whether or not the components retain any serviceability after the accident has occurred. Two aspects are considered, one is the response of a structure to an impulsive load that would arise directly as a result of an explosion, the other is the response to an impactive load that might arise directly as a result of some kind of impact or collision or subsequent to an explosion. In considering the former a new approach to investigating the susceptibility to buckling is introduced, one which could be applied to any structure. In the latter the specific case of pipe whipping is examined where both pipes are deformable. This is an extension of recent work carried out in this area at C.A.R.E. The finite element methodology applied is based entirely on the use of commercial software packages and, as has been demonstrated in other recent publications (Kormi and Islam, 1990 and Kormi, 1990), is of general applicability to the study of dynamic loading.
The inspiration for this work came from a recent finite element study of a buoyancy tank partially immersed in water (Kormi and Islam, 1989). Here the loading in the form of a shock wave was generated by detonation of explosive under water causing a spherical front to impinge onto the tank. Although the analysis produced complete information about stress, displacement and reaction forces the question of dynamic buckling was not addressed.