Further Revelation on Damage Detection by IAS Computed from the Contact-Point Response of a Moving Vehicle

The instantaneous amplitude squared (IAS) of the driving component of the contact-point response of a moving test vehicle was proposed for the damage detection of the sustaining bridge. As a supplement to the properties previously presented for the IAS, this paper is aimed at unveiling the key feature of the discontinuity amplification inherent in the IAS through the double guarantee of a “square operation” in the definition and a “second derivative” in computing the contact-point response. The capability of the IAS was demonstrated with regard to the effects of the environmental noise, vehicle damping and bridge damping in the numerical simulation. It is confirmed that the IAS can be reliably used in the damage detection of bridges by a moving test vehicle.