Response spectrum methods in tank-vehicle design

Existing design rules for tank vehicles have proved insufficient, because vibrations often cause fatigue cracks. Measurements have been performed on the tank to provide a picture of the influence of different road types and filling ratios. Shock response spectrum analysis (SRS) was used to obtain a measure of single-dynamic events. To get a basis for dimensioning against fatigue a calculation of fatigue-damage response spectra (FDRS) has been performed. This relates the vibrations in the tank to the risk of fatigue damage. In lieu of cycle counting by rain-flow count techniques, which has certain disadvantages, a new model, the so called HdM model, for fatigue-life assessment based on level crossing has been used. Further development of the results of the analysis can be used to improve design criteria in transport tank regulations, as well as to determine optimum inspection intervals for, in particular, tanks for hazardous materials.