Prediction of Modulus Changes During Fatigue in HSLA Steels

Stiffness and vibration frequency of automotive structures are shown to be dependent upon an effective modulus. Under typical loading conditions the effective modulus would be much less than the elastic modulus. The concept of the effective modulus ratio is introduced as a dimensionless quantity to describe the change in apparent modulus. It is shown that HSLA steels, specifically HI-FORM 50 and HI-FORM 80, are less affected than AISI 1005 steel.