Application of plastic analysis to the pipe whip problem

The problem of design against pipe whip is briefly reviewed and some methods of calculation applicable to the problem are considered. Emphasis is given to two methods of analysis.The first makes use of the ‘FRUSTA’ programme; this method only considers the moment deflections so that it can only be regarded as a simplified approach leading to approximate results.As an alternative, a fully 3-D plastic element method is considered (the PAPS element), the basic hypotheses being briefly reviewed. Comparisons between the two approaches are provided. Finally, a model including restraint aspects is discussed which allows the consideration of V bars, plastic elements, dampers and friction type restraints.Typical examples are given and discussed.