Which of the following about statically indeterminate axial or torsional shaft is NOT correct?
a. The maximum stress in the statically indeterminate structure may be reduced comparing to determinate structure, which is one of the reasons why statically indeterminate member/structure is commonly used in real-life
b. If number of unknowns is greater than the number of independent equilibrium equations, an axial or torsional loaded shaft is statically indeterminate
c. Simply by using equilibrium, we can solve the stress, strains, displacements or reactions of a statically indeterminate axial or torsional shaft problem.
d. Equilibrium, compatibility together with load-displacement relation may be applied to solve unknowns of a statically indeterminate axial or torsional shaft problem