DETERMINATION OF THE MOST DAMAGING OPERATIONAL LOADING MODES OF LOAD-BEARING STRUCTURES OF THE DUMP TRUCK BODY BY FATIGUE CRITERION

A procedure is developed for the calculation and experimental assessment of the operatonal modes damaging effect on the load-bearing structure of a dump truck body. The procedure makes it possible to determine the most dangerous zones of the load-bearing structure according to the multicycle fatigue criterion, as well as to assess the damaging effect of individual operatonal modes forming the dump truck working cycle. Analysis of the loading and fatigue damage accumulation of the load carrying structures of the BELAZ 7558 dump truck body was used for the procedure testing. Structure loadings have been determined for eight operating modes, including loading and unloading the body with bulk cargo during field tests. Processes of change of mechanical axial stresses during the tests were registered in eight zones. Experimental data analysis revealed two zones of the structure where the fatigue damage accumulation happens more than twice as fast as in the others. It is established that dump truck movement modes for technological road and the road in the dump area are characterized by the greatest fatigue damage accumulation. For the truck whole working cycle the most damaging movement mode for body is moving on the technological road. At the same time, the greatest unit equivalent fatigue damaging effect is formed by moving on the dump road and is greater than the corresponding value for the technological road by about 1.5 times. This is explained by the fact that the length of the technological road in the considered working cycle of the dump truck is 7 times more than the length of the dump road.