studying the effect of pulse shape on dynamic stress intensity factor at the finite crack tip using displacement fields

In analytical studies, step (heaviside) function is used to simulate an impact load. however, in real behaviour of materials, loading and unloading take a short time. the present study discusses analytically the effects of pulse shape and rising time of an impact load on dynamic stress intensity factor. firstly, a pulse load with positive slip (linear and non-linear) is applied on a cracked plate and the amount of dynamic stress intensity factor on the crack tip is obtained. then the effects of pulse time are discussed. results show that increasing the rise time decreases the stress intensity factor because of reduction of inertia effects. moreover, the duration of rise time plays the main role in dynamic stress intensity factor changes and how the variations are not matter.