|
|
|
@@ -80,7 +80,7 @@ Mechanical systems can fail due to a wide variety of reasons. The effect known a |
|
|
|
1. stress life, or |
|
|
|
2. strain life |
|
|
|
|
|
|
|
The first one is suitable for cases where the loads are nowhere near the yield stress of the material. In those cases where plastic deformation is expected to occur, strain-life methods ought to be employed. |
|
|
|
The first one is suitable for cases where the loads are nowhere near the yield stress of the material. When plastic deformation is expected to occur, strain-life methods ought to be employed. |
|
|
|
|
|
|
|
For the case study, as the loads come principally from operational loads, the ASME\ stress-life approach should be used. The stress amplitude of a periodic cycle can be related to the number of cycles where failure by fatigue is expected to occur. For each material, this dependence can be computed using normalised tests and a family of “fatigue curves” like the one depicted in\ [@fig:SN] (also called $S$-$N$ curve) for different temperatures can be obtained. |
|
|
|
|