Thermo-Mechanical Fatigue of Polymer Matrix Composites
PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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Thermo-mechanical fatigue occurs when a component is exposed to thermal cycling under mechanical constraint and or superimposed mechanical loading. Thermo-mechanical loading is an increasingly common service condition for polymer matrix composite materials. Unfortunately, little or no information is available regarding the behavior of polymer composites subject to this loading condition. The present thesis research program was undertaken to evaluate the effects of mechanical constraint on the response of polymer matrix composites during thermal cycling. Analytical and experimental techniques were used to characterize the response of carbon fiber reinforced cyanate ester IM6 BT3008 and bismaleimide IM75240-4 composites. Cross-ply laminates were subjected to thermal cycles from 24 to 177 deg C in the unconstrained, fully- constrained and over-constrained conditions. Laminate response, damage mechanisms and residual compressive properties were characterized for each material and degree of constraint. Predicted ply stress distributions are significantly different for the various degrees of constraint and are highly sensitive to temperature-dependent lamina properties and laminate stress free temperature. Predictions of laminate response correlate well with experimental results. Deviations are apparent at elevated temperature which are attributed to the effects of time-dependent deformation.
- Polymer Chemistry
- Laminates and Composite Materials