APPLICATIONS OF FRACTURE MECHANICS IN FAILURE ANALYSIS CASE STUDIES.

Concepts of linear elastic fracture mechanics were applied to study failure of an equalizing beam from a tandem rear axle of a highway tractor unit and the main beam of a flat bed trailer. In the first case, a crack initiated by stress corrosion cracking followed by fatigue crack propagation produced stress which was sufficient to produce brittle failure. Calculation of the fatigue life agreed with the number of cycles that the structure experienced before final fracture. In the second case, a combination of low temperature and high loading rate was sufficient to cause brittle fracture.