Control how temperature changes in a model are handled during an analysis.
The composite materials stored in the Composite Material Database are defaulted to have a stress-free temperature of 0° in the system of units specified by the 3rd argument unless the *CURE STRESS keyword is included in the HIN file. The *CURE STRESS keyword activates the thermal residual stress feature and forces Helius PFA to use the stress-free temperature specified in the material data file. Any initial temperature specified via the TREF command (including the default value of 0°) is used to calculate the residual stresses present in each of constituent and the composite due to the unmatched coefficients of thermal expansion between the fiber and matrix. For details on how the temperature changes imposed in a model affect how residual stresses are calculated, please refer to the Theory Manual.
It is also important to consider the particular values for the initial and final model temperatures as they are dependent on whether the thermal residual stresses are included. If they are included, the initial temperature value must be the actual initial temperature and the final temperature must be the actual final value. This is because Helius PFA calculates the ΔT from the stress-free temperature to the current temperature of the model. If the residual thermal stresses are not included, the initial temperature of the model should be 0° and the final temperature should be the ΔT between the temperature the material was characterized at and the final temperature. For a detailed example on the use of thermal residual stresses, refer to Example Problem 2.