Natural fiber-polymer composites are becoming increasingly important for load-bearing application due to their unique benefit of light weight and good mechanical performance. Polymers alone exhibit time dependent mechanical properties influenced by many environmental factors. More significantly, when natural fibres are present in the polymer matrices, the thermo-mechanical properties of such composites are changed by the environmental conditions and exhibit an internal and a global time dependent behavior. While durability analysis of the natural fibre-polymer composites is the main concern in real-life application, development of prediction methods is essential for evaluating their mechanical performance. Both temperature and moisture diffusion are known to influence the time dependent mechanical properties of polymer based composites; however, conventional analysis method considers the temperature factor only. Therefore, an evaluation technique is presented in this paper to describe the nonlinear visco-elastic behavior of natural fibre-polymer composites under concurrent temperature and moisture diffusion effects. Using an analogous approach to the TTSP, time-moisture superposition will be used to identify the moisture-dependent shift factors under an assumption that the effects of temperature and moisture can be decoupled and separately determined, and reassembled later on.
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