Issues with Inspection Hammers for Daily Wheel-Nut Inspections of Heavy-Duty Vehicles and a Fundamental Study on a Novel Impact-Hammer Test

To mitigate wheel-separation accidents involving heavy-duty vehicles, a new impact-hammer technique has been developed that enables rapid, quantitative diagnosis during daily pre-trip inspections. Conventional inspection hammers detect only a 0 % wheel-nut torque ratio, offering no gradation of fastening integrity. In the proposed method, the tip of a stainless-steel rod is struck with an accelerometer-equipped hammer, and the resulting response waveform is analysed; the peak time lag (delay time) between its deformation and recovery phases is used as the diagnostic index. Analysis of this delay time showed that the technique can be applied to evaluating the fastening integrity of wheel nuts.