Thermal ageing of polymer-matrix composite materials of any long-life spacecraft in LEO involves evolution of mechanical, thermophysical and morphological properties, especially if the structure operates under external mechanical stress like bending. Behavior of KMU-4l carbon/epoxy composite material under combined effect of thermal profiles and static mechanical loading has been studied in a simulated LEO space environment. Thermal cycling was performed on specimens under bending stress reaching 30.4 % of the material ultimate strength. Specimens subjected to combined thermal and mechanical fatigue were examined in a series of 4 intermediate points with a maximum of 120 cycles. The DMTA technique has been employed to follow the global thermomechanical response of KMU-4l composite. The degradation produced was detected by moisture diffusion analysis, the crack density was estimated at the edges of the specimens using a scanning electron microscope. Effects such as the temperature dependence of material properties and matrix post-curing phenomena are also discussed. The results are compared with the appropriate data obtained on specimens of KMU-4l exposed for up to 1501 days to LEO space environments onboard SALYUT and MIR space stations.
Predictive model for microcracking and mechanical properties of polymer-matrix composite materials for space applications
2003
6 Seiten, 12 Quellen
Aufsatz (Konferenz)
Englisch
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