Failure criteria for use in the design environment

This paper is concerned with the comparison of composite failure data with the design criteria used for the design of GRP process equipment. This industry sector makes extensive use of composite materials and employs a pragmatic approach to design. Full details were discussed in Part A of this exercise. Examination of the test data yields a number of issues associated with what must be included within a predictive capability, such as the correct interpretation of stress strain behaviour, the use of appropriate material constants, and a thorough understanding of the test methods used to measure material and component responses. Not all of these points are relevant to the design of structures for long-term service as design strains are limited to low values and not all combinations of load apply. Given the relative simplicity of the design methods used it is considered that the correlation between calculation and measurement is satisfactory. Some improvements are possible and these are the subject of consideration in the on-going revision of standards documentation.