Design and Analysis of Fatigue Testing Machine for Twist Drill

Abstract

Fatigue is the process of progressive localized permanent structural change occurring in a material. It occurs when a material is subjected to repeat loading and unloading. If the loads are above a certain limit, microscopic cracks will begin to form at the stress concentrators such as the surface and at grain interfaces. Eventually a crack will reach a critical size, and finally the material will suddenly fracture. So the shape of the material will significantly affect the fatigue life. Fatigue testing gives much better data to predict the in-service life of materials. Drill is used to create the hole on the work piece. While creating the hole drill has to be undergoes into compression and bending. It should be check for bending. So that the machine set-up has to be designed in CAD software and check the machine set-up for different loading condition. The aim of this thesis work is to discuss a rotating beam type set-up is designed and it is used to estimate the fatigue life of twist drill. The design principle of structure of fatigue test machine set-up was based on the adaptation of the technical theory of bending of beam. Components/materials selection was based on functionality, durability, cost and local availability. The major parts of the machine: the machine main frame, the bearing, the rotating shaft, the bearing housing, sensor, speed counter, dead weights, electric motor. The rotating beam type fatigue testing method can be used, because it's having simple working principle compared to the other principle.