Influence of stress to mechanical failure of long tail shaft in the power transmission system on local fishing boat

Abstract

This research focuses on a study of failure mechanism of long tail shafts which are major machine
components in mechanical transmission systems of diesel engines in the cut-stern Kolek boats, the important
traditional fishing boats for fishermen in Kaoseng community, located on the Coast of Songkhla Lake. From onsite
data collection of the failure of long tail shafts, it appears that the shaft suddenly fractures into two pieces while
operating. When investigating the failure of shafts by examining on surface cracks, it shows that cracks initiated from
the fillet shoulder of shafts. By analyzing the failure mechanism, it reveals that the weak point of shafts is at the
area which has a high concentration of stresses. In the experimental program for the data above, different loadings
are applied to long tail shafts to evaluate which load that the mechanisms of failure occurred. The conditions of
loadings are No-load, Full-load, and Over-load. The benefit of this research will be used in designing new and
appropriate long tail shafts.