The safety-factor calibration of laminates for long-term applications: behavior model and reliability method

This paper presents a method for determining safety factors which must be taken into account when designing laminates for long-term applications. The method requires two steps: the first is a behavioral model able to predict time-dependent phenomena, and the second is a reliability method. The meso/macro approach is used in the behavioral model. This paper presents a damaged elasto-viscoplastic model able to predict the behavior of a layer made of a polymer reinforced with unidirectional fibers. This model requires a non-linear laminate theory which provides the response of laminate structures. The method for calibrating safety factors is based on the first-order reliability method. A description of the behavioral model in this method is presented. Finally, as a working example, the design of filament-wound pipe for fluid transportation is presented. A functional criterion is introduced to prevent leakage. The effect of material parameters is analyzed.