Another problem with the composite testing arises when the loading directions do not coincide with the symmetry axes of the specimen. This situation gives rise to coupling between the normal-shear modes. This results in extraneous forces and deformations in the coupons. For example, a coupon in tension will exhibit the in-plane shear and a coupon in bending will exhibit the additional twisting. Further, if the laminate has layers oriented with respect to each other then there will be mismatch of interface deformation due to different degree of tension-shear coupling of adjacent layers. This may lead to delamination. The severity of the mismatch of interface deformation depends upon various factors like stacking sequence, test modes, degree of asymmetry, end constraints, etc.

Thus, to summarize, the main practical consequences of anisotropy are as follows:

1. There will be severe end-effects, which extend in the direction of higher stiffness. Further, this is a function of both the specimen geometry and the anisotropy.
2. A premature failure in grips or at other loading points may occur.
3. A premature delamination at free edges or other unintended failure modes may take place. These failures emanate from the interactions between the macrostructure of the composite and system of external forces.
4. There can be property imbalances of the lamina. For example, a tensile modulus (or strength) which is dominated by the properties of the fibre and a shear modulus (or strength) which is dominated by the properties of the matrix.