Concept of Creep and Fatigue Life Prediction for Polymer Composites

Wolfram, Bundeswehr Research Institute for Materials, Fuels, and Lubricants, Germany 

Miyano and Nakada proposed an accelerated method for the prediction of long-term creep and fatigue strength of FRP laminates on the basis of relatively few constant strain rate and fatigue loading tests. The following description of the methodology was first published in [1023]. This method is based on four assumptions  

Hypothesis B states that the same time-temperature superposition principle applies for all three types of strengths (CSR, creep, and fatigue). This means that the shift factors for all three types of strength can be assigned the same value. The first master curve of CSR strength can then be constructed from the test results for various constant strain rates and temperatures. 

Hypothesis D states the linear dependence of fatigue strength on the stress ratio R. Using this hypothesis, fatigue master curves for various stress ratios can be plotted. 

Because of the broad variety of possible composite structures, it cannot be assumed that all hypotheses apply for every particular material. The application of the proposed accelerated prediction method presumes operating experience with composite materials. 

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Concept of Creep and Fatigue Life Prediction for Polymer Composites... 

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