60 Second Spotlight on Jeferson Oliveira, The Open University
Ahead of the Residual Stresses webinar taking place on 24 June we caught up with Jeferson Oliveira to hear his thoughts on the topic.
Briefly describe your current role and research interests.
I currently lead residual stress measurement and material characterisation projects that require the quality and rigour of academic research, but with fast turnarounds and/or confidentiality requirements which are not compatible with academic research or collaborations.
Why should engineers care about residual stresses—what’s at stake?
Residual stresses are present in practically every solid object. It plays a critical role in distortion, fatigue and corrosion cracking and it can be an asset or a liability. If they are engineered, they can improve mechanical performance and minimise waste, but if neglected, can lead to catastrophic failures (an extreme example is the capsizing of an oil platform due to a 6 mm-long weld that was not properly treated).
What first sparked your interest in residual stress engineering?
From my mechanical engineering degree, I knew they existed, but I was blown away by the fact that there were multiple ways to actually measure them, when at the time I couldn’t even fathom how one would go about it. Now I see more and more companies interested in manipulating these stresses to extract the full potential performance from their materials.
What’s the most surprising thing you’ve learned in your 12+ years in this field?
It still baffles me that residual stress engineering is still not widespread in mechanical and design engineering and in general how little knowledge stress engineers have about the topic.
What’s one common myth or misunderstanding about residual stress?
A common myth that residual stresses are harmful and should be removed. If you’re trying to control distortions, then yes, you’d want to avoid them. However, once you have your final geometry, the residual stress distribution can be engineered in a way to improve mechanical performance without even changing the design or materials – just by optimising the manufacturing process. The gains can be quite substantial, particularly fatigue strength!
Which industries are seeing the biggest impact from residual stress control today?
Mostly aerospace and power generation (nuclear and non-nuclear), but also high-performance applications, such as Defence and F1, where sometimes every gram counts.
How do you see residual stress engineering evolving over the next decade?
Additive manufacturing (AM) is bringing quite a bit of attention to residual stresses, since AM parts are quite prone to warping, which is caused by residual stresses. What I’d like to see is wider awareness and the development of tools to make it easier for stress engineers to design parts with residual stress engineering in mind, instead of simply relying on the strength of the material to withstand operational loads. The hardest hurdle we have in the space is to educate other engineers on the potential benefits of residual stress engineering, which are still vastly untapped.
Who would benefit most from attending your webinar on 24 June?
Anyone involved in additive manufacturing, safety-critical mechanical components, welding or high-performance applications. In my lecture, I’ll make sure to include examples from the various industries I’ve worked with to get everyone thinking about how they can implement this in their design workflow.