Statistical variations in the elastic properties of composites are unavoidable. This work is concerned with the assessment of the probabilistic first ply failure of pressure vessel in response to the variations of elastic properties of T700 carbon/epoxy composite among the published literature. Initially, deterministic failure pressure is estimated using Finite Element Analysis software ANSYS. The uncertainties with respect to elastic properties are quantified by using Statistical software MINITAB. Then, the probability design system platform in ANSYS software has been utilized to perform probabilistic failure analysis by Monte Carlo simulations. The statistical results in terms of the mean and standard deviation of first ply failure pressure are computed. The probabilistic first ply failure pressure range determined is within 3 limits with 99.997% confidence level. It is helpful to the designers to assess the factor of safety in the case of anticipated variations in properties.

Metallic and metal-lined polymer composite pressure vessels are extensively used in industries including aerospace. In the absence of unique failure criteria for the structural elements, phenomenological or empirical methodologies always fascinate the researchers. This paper deals with comprehensive methodologies in the prediction of burst pressure of metallic and metal-lined polymer composite pressure vessels for aerospace applications. Metallic pressure vessels are analyzed using Ansys software considering the elastic-plastic nature of materials. The progressive analysis is carried out in metal-lined composite pressure vessels in an explicit mode using Ansys software. The problem of solution convergence is discussed in detail. The extent of degradation in static analysis is suggested after multiple analysis trials. In the unit pressure extrapolation technique, stress components are evaluated using Ansys software, transformed into the local coordinate system and hence failure pressure of the first ply is identified by maximum stress criterion. Then the analysis is continued with degrading of failed layers using Ansys software and successive failures of layers are identified in steps. The results of burst pressure, evaluated through the present analyses show good agreement with the published test results. The procedures described in the paper would be of interest to the designers of pressure vessels.