Based on the visual inspection and metallographic examination it was confirmed that the curvilinear crack growth on the
frame rail was a fatigue failure and crack initiations was due to apoorquality drilled hole on the frame.The crack path
obtained was influenced by mixed-mode stress intensity factors.The simulation results obtained were used to understand
the root cause of failure and can be used to recommend design modifications to prevent such extensive fatigue failure of
heavy duty truck frame.