Fatigue test lab report

Fatigue is an interesting phenomenon in that load-bearing components can fail while the overall stress applied may not exceed the yield stress. Too much flaws will result the specimen fail faster. It will increase the fatigue limit and lifespan of the specimen.

Fatigue test is carried out for

This technique could enhanced the surface hardens and the fatigue life. Study the increase in the magnitudes of the applied stress affect the number of cycles to failure 2. Using fatigue limit we can approximately determine other mechanical property like ultimate tensile strength. Even though this failure is slow in coming but the disastrous fatigue failure can happen very sudden. Most of nonferrous metals does not have fatigue limit. Name the material that does not have a fatigue limit Example of material that does not have a fatigue limit is nonferrous alloy aluminum, magnesium. So, components fail by fatigue because even through the overall applied stresses may remain below the yield strength. Beside eliminating sharp surface discontinuities and imposing surface residual compressive stresses by shot peen-ing also can increase fatigue life.

It can be reduce by polishing the surface. Radius of the fillet. Beside eliminating sharp surface discontinuities and imposing surface residual compressive stresses by shot peen-ing also can increase fatigue life.

This can be done by Increase the fillet radius of the specimen.

Torsion test lab manual

This is because if we know what is fatigue limit of one material, we will know what is the maximum allowable load per infinite cycle of that can be sustained by the material. The parameters such as mean stress and test frequency should be controlled. Fatigue failure occur in three stages, first stage, small crack initiate at the surface where the stress is at maximum, and include surface defects such as scratches or pits, sharp corners due to poor design or manufacture, grain boundaries, or dislocation concentration. However, when the stresses occurs a sufficient number of times, it causes failure by fatigue. Imposing residual compressive stresses within a thin outer surface layer also could increase the fatigue performance. The revolution counter was set to zero and the main switch of the inverter speed control was turned on. The importance of fatigue limit The fatigue limit is important for machinery in industrial or engineering design to avoid any hazard. Case hardening applied to the specimen. The lock nut and spring load is loosened. This technique could enhanced the surface hardens and the fatigue life.

Using fatigue limit we can approximately determine other mechanical property like ultimate tensile strength. Thus a surface tensile stress of external origin will be partially nullified and reduced in magnitude by the residual compressive stress.

sources of error in fatigue test

The parameters such as mean stress and test frequency should be controlled. It is one of the few failures that occur to materials. In the left end, the conical part is attached to the motor shaft and the lock nut is tightened thoroughly using wrenches.

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Fatigue Analysis Report_ Final