Effect of initial T-stress on stress intensity factor for a crack in a thin pre-stressed layer

• A double-clamped beam is presented to model a crack in a prestressed elastic layer.
• Stress intensity factors are derived for a cracked layer with initial T-stress.
• The influence of the initial stress on crack growth is discussed.
• Tensile/compressive initial T-stress impedes/promotes crack growth.

Fracture of a pre-stressed thin elastic layer is studied and modelled as bending of double clamped beams with axial force. Using the beam theory, the strain energy in bending state of the beam with an axial force is derived. Explicit expressions for energy release rate and stress intensity factor (SIF) for a crack with initial transverse stress (T-stress) are obtained. Results show that tensile (compressive) initial T-stress decreases (increases) the SIF and impedes (promotes) crack growth. The influence of compressive initial stress is greater than that of tensile initial stress in the same magnitude.