Implementation of RankFourTensor member function "contractionIj"

[bbist196]

Hello Everyone,

I am trying to get the strain energy density by using elastic tensor (not using stress and strain) with the following equation

_strain_energy_density = (½) * ((_mechanical_strain) : (_elasticity_tensor) : (_mechanica_strain))
i.e.

For this, first of all, I made the double contraction using member function "contractionIj" of RankFourTensor _elasticity_tensor with the RankTwoTensor _mechanical_strain to get _stresss as follows

And then I computed the _strain_energy_density using double contraction using member function "doubleContraction" of _stresss and _mechanical_strain following the equation given below

For this, my source code snippet is as follows:

With this snippet in the the src code the app compiled well. But on running simulation, produce the RankTwoTensor of _stresss with all element zero as printed below

However, the printed non zero _elasticity_tensor (isotropic linear elastic tensor) and _mechanical_strain are as follows:

Here, no input parameters (_elasticity_tensor and _mechanical_strain) are zero producing zero _stresss.
So, It is suspected to have error in the use "contractionIj" member function in the following src code snippet

Could anyone please help me out whether this is the correct way of using "contractionIj" member function??

Note: You can find the reference for the "contractionIj" member function defined for RankFourTensor here [https://mooseframework.inl.gov/docs/doxygen/moose/classRankFourTensorTempl.html#a2b47567b94f148cc5b30bbb3739e80f1]

Further, files needed to check the module are available here:
[https://github.com/bbist196/bright_star]

Your help will be greatly appreciated.

Thank you.

Thankyou