Design of Pressure Hulls Using Nonlinear Finite Element Analysis

Through the use of nonlinear finite element analysis (NLFEA), submarine pressure hull designs could potentially be based on calculated limit states that include the full geometric complexity of the structure, and real-world effects such as build imperfections. In addition, NLFEA could provide a rational means of assessing the effects of in-service damage on structural performance. Analysis of pressure hulls using 3D NLFEA is not currently supported in design codes, primarily because the uncertainty regarding the accuracy of the method has not been quantified. Defence Research and Development Canada (DRDC), the R&D branch of the Canadian Navy, is undertaking work to develop a partial safety factor for 3D NLFEA of pressure hulls, by comparison of numerically calculated collapse pressures to experimental results. Data from experiments previously conducted at various institutions will be augmented by a pressure hull testing program currently being undertaken by a joint project of DRDC and the Ministry of Defence of the Netherlands. The development of NLFEA modeling and analysis guidelines, as well as a revised design/analysis procedure, will be discussed, as well as a history of the DRDC submarine structures research program.