M. Carboni

Defects and in-service fatigue life of truck wheels

Abstract Truck wheels are usually assessed against fatigue by experimental tests based on standardised load sequences (CARLOS load spectra) which reproduce a typical service life of the real component. The present paper deals with the effect of defects, caused by the manufacturing process, on the fatigue life of wheels subjected to block loading tests. The research was prompted by premature service failures of a batch of truck wheels. The investigation firstly dealt with fatigue and crack growth tests for the quality control of the material and then with the detection of defects at the origin of the unexpected failures. The data have been used to assess the acceptability of defects and to estimate life under proof tests using current crack propagation models.

The Influence of Constraint on Fitting Fatigue Crack Growth Data

Fracture mechanics, in terms of crack propagation, is one of the most popular approaches for life prediction of components and structures subjected to fatigue loads. Experimental tests (as an example for a structural steel see Fig. 1) are carried out in order to quantify crack growth rates and thresholds.