[Ma cHAO]

Question:
The solids4Foam solver uses the total Lagrangian formulation and the updated Lagrangian formulation to compute large strains and rotations of solids, which is different from the usual solid dynamics that considers linear and angular momentum. I see that the boundary condition implementation takes into account the case of fixed rotation, does this mean that this solver automatically satisfies the conservation of angular momentum, i.e. the nonlinear geometric method solver can also be applied to rotational problems, such as the rotation of 3D beams (rotation)？
This problem comes from comparing the solids4Foam toolbox with the explicit dynamics toolbox -'explicitSolidDynamics', which I saw in the source code has a posteriori angular momentum projection algorithm for angular momentum conservation.
Angular momentum is not necessarily conserved, as the deformation gradient F is no longer 'strongly' obtained as the material gradient of the current geometry, as mentioned in "A first-order hyperbolic framework for the computation of dynamics of solids with large strains: a total Lagrangian scheme centered on the upwind cell".
I'm not quite sure how this is considered in solids4Foam.

[amuzeshi]

Originally Posted by Ma cHAO

Question:
The solids4Foam solver uses the total Lagrangian formulation and the updated Lagrangian formulation....

As far as I know, in the most general form, the conservation of the angular momentum reduces to the Cauchy stress tensor being symmetric, i.e., reducing the number of unknowns by 3 (it is not true in the presence of body torque, for example in magnetic materials.)
Therefore, like you said, the only equation to be solved is the linear momentum equation.