Hi Oussama,

I assume that you are inverting the theoretical equation for crack flank displacement to determine the Stress Intensity Factor (SIF), assuming that the material is linear elastic.

I also assume that compression loads will tend to cause the crack flanks to contact each other. The SIF will be zero if the crack flanks are pushed together near the crack tip.

However, there are some conditions when the crack flanks might be open even when the external loading is compressive. For example, this might happen if there are tensile residual stresses.

Does that help at all?

Regards,

Simon

Thank you for your answer, yes the material is linear elastic. in some cases, the crack flanks stay open. If the SIF is zero in this case does that mean the crack will not grow?

Hi Oussama,

What material are you analysing and what is the mechanism of crack growth?

I apologise, I have just thought that I was only thinking of Mode I loading. I suppose there may be modes II and III even when the crack flanks press against each other. Is this likely, and if so, are you modelling the frictional resistance to the sliding of the faces over each other?

Regards,

Simon

If stress intensity factor does not exceed a critical value known as the fracture toughness, fracture will not occur.