The life expectancy of a structural component is predominantly determined by the interaction between defects in the object and the stresses to which it is subjected. These stresses are the result of stresses applied in service, compounded with those that develop in the object during manufacturing and machining processes, commonly termed residual stresses. These residual stresses can add to operating loads thus accelerating the growth rate of defects and leading, in some cases, to premature failure of parts, with very serious economic implications.
Although applied stresses are generally taken into account in design engineering, residual stresses are often overlooked being intricately correlated with the material, the manufacturing processes and heat treating and also being able to change during operation.
There is also a limited awareness of the affect of these stresses on the performance of a component and consequently of the potential economic benefits that could ensue from their being accurately evaluated.
Hence the reason for organizing theoretical-practical courses on residual stresses with the following objectives
- to present the concept of residual stresses and the affect of residual stresses on the strength of metal parts from a theoretical viewpoint;
- to discuss practical cases where the transformation processes can introduce residual stresses (for example, welding, molding, heat treating);
- to offer a full rundown of applications of this technique, both where residual stresses are negative for performance of the object in service and when they are deliberately introduced into an object to raise its fatigue limit (eg, by shot peening) and they therefore have to be quantified.