1. A modeling method for a fibrous material to be made into a tampon product, the modeling method comprising: analyzing processes and conditions under which the fibrous material is made into the tampon product; determining that moisture, temperature and rate conditions should be tested according to the analysis of the processes and conditions; testing the fibrous material under at least one of moisture, thermal or rate conditions similar to those under which the fibrous material is made into the tampon product to obtain test results; defining a constitutive model for the fibrous material using test results to identify behaviors and assembling a set of coupled non-linear partial differential equations that describe the behaviors; and providing a computing device to utilize the defined constitutive model for the fibrous material.