Fatigue/Strength Test

Key words�

The maximum stress of without causing damage after the material has experienced infinite times of alternating load is referred to as fatigue strength and fatigue limit.

The fatigue life of parts is related to the stress and strain level of parts, the relation of which can be shown via stress-life curve (o-N curve) and strain-life curve (ε-N curve). Stress-life curve and stress-life curve are generally referred to as S-N curve.

Fatigue test refers to test the fatigue limit σ-1 of material by exerting symmetrical alternating load and then draw the S-N curve of material to further observe the fatigue destruction phenomenon and the fracture characteristics.

Strength test refers to the test as conducted for finding out the ability of not causing damage on the material or the bearing capacity of structure. Strength test includes material strength test and structural strength test.

Material strength test tests the material’s limit of yielding, ultimate strength or fatigue limit, or fatigue limit, and other indexes. The structural strength test tests the maximum bearing capacity of structure. It is not only related to the material strength, but to the geometrical shape of structure, mechanism accessories, external force, etc. as well. According to the test’s way of loading, it can be divided into static strength test, dynamic strength test, fatigue strength test, etc. According to the environment temperature, it can be divided into natural temperature strength test, hot (high temperature) strength or freezing (low temperature) strength test, etc.

Multiseat fatigue test

Static strength loading test of valve