What is residual stress? That’s a very common question when you work at Hill Engineering. Many of our customers, friends, colleagues, and family members like to ask us questions about residual stress including: What is residual stress? How do you measure it? How does residual stress affect material performance? If you have questions about these topics, you’ve come to the right place. At Hill Engineering we love to talk about our work and we have a lot to share about residual stress.
What is residual stress? In a very basic, non-technical sense residual stress is stress that is locked in a material during manufacturing. Just like with our bodies where we sometimes have tightness in our muscles, there are regions in materials that are under stress as they are pulled or pushed by the surrounding material. We refer to these internal stresses as residual stresses because they exist within the material itself.
Applied stresses develop when the material is loaded by outside forces. Going back to our human body example, residual stress is the tightness that you feel in your shoulders while standing or sitting. Applied stresses arise when you pick up something heavy. The applied and residual stresses combine together to determine the ultimate strength or performance of the material. For example, if the residual stresses are large the material will not be able to sustain as much applied stress.
As engineers we care about residual stresses because they affect material performance. Often structures are designed with considerable safety factors and the effects of residual stresses can be ignored. But as we push for higher performing structures that operate closer to the cutting-edge of technology, factors like residual stress can be the difference between successful performance and structural failure.
That’s a simple answer to the question of what is residual stress. There are, of course, much more in-depth technical explanations that we can share with you as well. At Hill Engineering we work with residual stress on a daily basis. For example, we are experts at residual stress measurements and fatigue analysis accounting for residual stress effects. Please contact us for additional information.