When the state of stress is represented by the ( ), no shear stress will act on the element. Thestate of stress can also be represented in terms of the maximum in-plane shear stress. In this case, ( ) will also act on the element.
A.
the principal stresses, an average normal stress
B.
the maximum in-plane shear stress, an average normal stress
C.
an average normal stress, the principal stresses
D.
the maximum in-plane shear stress, the principal stresses