Multicriterial optimization of the test conditions of structures subject to random loads

The forced testing of structures subject to random loads is the important stage of providing reliability and long service life of already produced and design machines. When choosing and validating the regimes of this testing several contradicting criteria should be met.From one hand, we need to load the tested unit in such a way that the loads on dangerous zones are as close as possible to those which take place during service conditions. The same is true for following the service-stress/time history:the sequences of high and low loads in each dangerous cut during service and test rig regimes must be maximally close. From the other hand, the test must be completed in shortest time to provide for operative forecost of the structure service life,i.e. it is necessary to accelerate the process of cumulating the fatigue damages due to forced high loads compared to service conditions.Thus three criteria for estimating the quality of testing regime may be distinquished: validity, service-stress/time history, and f orcing degree. Basing on these criteria, the engineer chooses the regime.