Modeling for suppression of moisture/temperature induced dimensional changes in unbalanced fibrous composite structures with periodic bonding

Suppression of dimensional change induced by moisture and temperature chang e is studied for unbalanced structures composed of at least one hygroscopic component. An unbalanced parallel structure with periodic bonding is model ed, taking into account various parameters such as moisture content and tem perature at the time of assembly, molecular orientation, and bonding length . The results show that two factors play a major role in moisture/temperatu re induced dimensional change: longitudinal swelling/shortening and materia l softening/stiffening. Whether the two factors add their effects to each o ther or compete against each other depends on the moisture content and temp erature at the time of structural. assembly. There is a range of critical a spect ratios over which the structure is dimensionally stable. This range i ncreases with increasing width and thickness ratios, and decreases with inc reasing initial moisture regain, initial temperature, and orientation facto r.