Pressure-impulse (P-I) diagrams are commonly used for assessment on blast resistance capacity of corrugations on offshore cabins for given blast-loading scenarios or in the early design. Current methods such as experimental models, analytical models and Nonlinear Finite Element Analysis (NLFEA) models could be used to generate the P-I diagram. However, each single model has certain shortcomings in despite of its advantages. Based on the convenience of analytical model and the accuracy of numerical model, this study presents a numerical procedure to derive analytical formulae to easily generate P-I diagram for corrugations with NLFEA method. Numerical model of corrugations which considers strain rate effect, buckling and membrane effects and adopts an equivalent plastic strain based failure criterion is built. Parametric studies are performed to investigate the parametric effects on the P-I diagram. Based on the numerical results, analytical formulae to predict the P-I diagram are derived. An experimental case study shows that the proposed analytical formulae can be easily used to generate P-I diagram for corrugations. The results are also compared with those obtained from the SDOF approach. It is shown that the proposed procedure gives better prediction of P-I diagram than the SDOF approach. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All.rights reserved.