The penny-shaped crack problem in micropolar thermoelasticity

The axisymmetry problem of a penny-shaped crack opened out by thermal loads is studied. The linear theory of micropolar elasticity is employed. Two types of thermal loads are considered—prescribed temperature on the crack faces and prescribed heat flux across the faces. It is shown that, in both the cases, the problem is equivalent to the isothermal problem of the crack opened out by suitable normal tractions on the crack faces. The stress intensity factors are found to depend on, in addition to the usual parameters, two parameters N and M; N is a number characterising the coupling of the displacement field with the microtation field and M is the ratio N/τ where τ is a non-dimensional material characteristic length. The classical values of the stress intensity factors are recovered as a limiting case. Numerical results are presented for the case of constant heat flux across the crack faces. These results show that the presence of couple stresses elevates the values of the stress intensity factors.