Temperature-dependence of elastic properties for residual stress computation

[Anonymous]

Dear Moldflow developers,

Are the elastic properties (9 moduli for anisotropic materials) considered as temperature-dependent (E(T) for instance) for residual stress computation? In the material database they are measured at a constant temperature (25 C maybe). However during the calculation of thermally induced residual stresses it's nice to consider them as T-dependent since the temperature should be high before ejection.

[franco.costa · Accepted solution]

Hello Tianyi,

considering the temperature dependence of the elastic modulus would be useful if / when we consider viscoelastic stress relaxation. In the standard commercial release codes we do not have stress relaxation, therefore temperature dependence of modulus would not add any benefit.

The warp deflection solution is based on the accumulation of strain values due to residual stresses(strains) and thermal shrinkage. These thermal stresses are calculated using the coefficient of thermal expansion - which is also quoted in the material database at room temperature - but is modified to account for temperature dependence during the calculation of strains/deflections.

[Anonymous]

Thanks for your reply Franco. I understand better now.