Calculation of the moisture concentration field in a multilayered plate

Thus, we have developed an algorithm and program to calculate fields of moisture concentration in a laminated plate for steady external temperatures and moisture contents. A test calculation and comparison of some of the findings with previous results demonstrated the accuracy of the program for solving a number of diffusion problems. For example, the program can be used to evaluate the life of the moisture-protective properties of polymer products, as well as to model moisture absorption in fiber composites. Curves of moisture concentration were calculated for a unidirectionally reinforced (with organic fibers) plastic at different relative humidities. We also calculated sorption curves and isotherms, which were shown to agree satisfactorily with previous empirical curves. It was shown that it is possible to approximately evaluate the sorption behavior of a unidirectionally reinforced fiber composite by means of a three-layer model and to analyze the stability of the result against an increase in the number of layers. For the two-component composite examined here, sorption behavior deviates from the classical behavior described by Fick's law - although the components of the composite obey this law. The algorithm and program that were developed make it possible to evaluate the kinetics of moisture absorption in complex composite systems and determine the distribution of moisture among and within the components. The study described here was conducted under grant 93.176 from the Latvian Science Council.