Determine the number of equations to find out the unknowns for a 3D structural body having 15 unknowns.
1
6 Equilibrium equations, 3 stress strain relations and 6 strain displacement relations
2
6 Equilibrium equations, 6 stress strain relations and 6 strain displacement relations
3
6 Equilibrium equations, 6 stress strain relations and 3 strain displacement relations
4
3 Equilibrium equations, 6 stress strain relations and 6 strain displacement relations