I am currently trying to run a simulation to predict thermal stress in a matrix & fibre composite with a change in temperature whilst cooling. My analysis runs and gives values but I know from the theory that the inner material should give a negative reading and then as it transitions through to the outside material it will become positive due to the difference in coefficient of thermal expansion of the two materials. Unfortunately I don't get a compressive stress value from the inner material!
If anyone could shed some light on why my model wouldn't show this that would extremely helpful!!
I've attached some pictures for visual explanation.