Читать книгу Root Cause Failure Analysis - Trinath Sahoo - Страница 87

Before explaining how to diagnose a failure, we should review the effects of stress on a component. When a load is put on a part, it distorts. In a sound design the load isn’t excessive, the stress doesn’t exceed the “yield point,” and the part deforms elastically, i.e., when the load is released the part returns to its original shape. This is shown in Figure 5.1, a “stress–strain” diagram that shows the relationship between loads and deformation. In a good design, the part operates in the elastic range, the area between the origin and the yield strength. Beyond this point, the part will be permanently deformed, even greater increases in load will cause the part to break.