| Design by analysis methods by means of finite element analysis are being used to establish structural efficient and safe pressure vessels. This research looks at developing a general procedure for pressure vessel design analysis based on full elastic-plastic analysis (including large deformation and strain hardening effects) via a general criterion of plastic collapse named ‘Ratio Plastic Work Curvature’ criterion. The design procedure reduces the level of uncertainty in the design process and safer more economical structurally efficient designs. 
Further research work is being conducted on composite pressure vessels. A series of realistic tests have been conducted to monitor the first ply failure load, strain and volume change progression and ultimate failure. Numerical models that predict the design load of GFRP pressure vessels and pipes have been developed and validated with the experimental test results. The influence of combined loading on the ultimate failure strength of pipes is also being investigated. | 
