Testing and fatigue life assessment of timber truck stanchions

Abstract

Components of transport trucks are subjected to dynamic cyclic loads. The magnitude of these loads depends on road conditions and cargo mass. Cyclic loads can cause fatigue failure at stress levels significantly below the yield strength of the material. When calculating fatigue, it is necessary to determine the actual loads acting on the structure under working conditions. In this study, stanchion displacements of overloaded timber trucks were measured under both static and dynamic loads. For the specified mass of timber, a history of dynamic loads acting on the stanchion was obtained. Then, based on the finite element analysis, stress concentration points were determined within the base material and welded joints of the stanchion. The history of maximum stresses at concentration points was determined. Stress ranges and mean stresses for the load history were calculated using the rainflow fatigue cycle counting method. Repeats to failure were determined on the basis of the Palmgren-Miner cumulative damage rule and the modified Goodman correction for the points with the highest stress level. Experimental investigation of the actual load history of the stanchion of significantly overloaded timber truck allowed to determine the mileage to potential failure.