Question

What is meant by endurance strength of a material? How do the size and surface condition of a component and

type of load affect such strength?​

Answer 1

Explanation:

Endurance limit refers to the fatigue strength of a material when subjected to repeated (cyclic) loadings of various types and ranges. Some materials, e.g. steels have a load limit which, if not exceeded will exhibit a capacity to resist such loading, i.e. cracking. Other materials, e.g. aluminum alloys, will have propagating cracks even at low load levels. This branch of materials engineering is called Fracture Mechanics. It is a reason why inspections of aircraft constructed from aluminum must be subject to periodic inspection.

Note that the endurance limit of a material is exhibited by the S-N fatigue curve and shows susceptibility to failure at levels below the ultimate, yield or other failure stress levels. Stress concentrations, due to geometry, surface roughness and similar conditions also adversely affect the fatigue strength.