Rectangular and rhombohedral inclusion reinforcements

Results show that the singular stress field predicted by the linear elastic solution for the rigid inclusion model can be generated in reality, with great accuracy, within a material. In particular, photoelastic experiments:
  • agree with the fact that the singularity is lower for obtuse than for acute inclusion angles;

  • show that the singularity is stronger in Mode II than in Mode I (differently from a notch);

  • validate the model of rigid quadrilateral inclusion;

  • for thin inclusions, show the presence of boundary layers deeply influencing the stress field, so that the limit case of rigid line inclusion is obtained in strong dependence on the inclusion’s shape.

Thin inclusion reinforcement (stiffener)

The presence of a second phase in a matrix material leads to inhomogeneity in the mechanical fields.
The theoretical solution of a zero-thickness, infinitely rigid line inclusion embedded in an elastic material has the following features:
  • Similarly to a fracture, a square-root singularity in the stress/strain fields is present at the tip of the inclusion;

  • In a homogeneous matrix subject to uniform stress at infinity, such singularity only arises when a normal stress acts parallel or orthogonal to the inclusion line, while a stiffener parallel to a simple shear does not disturb the ambient field.
We have confirmed these characteristics through photoelastic transmission experiments.

We have also shown the possibility of the emergence of shear bands at the tip of the stiffener.

Related papers:

Back to main page