Ring Core
The ring-core technique is a mechanical measurement method used to determine principal residual stresses incrementally with depth.
This technique can be used on metals, ceramics, and polymers. Materials that can’t be tested by X-ray diffraction, such as coarse grain or amorphous materials, can be tested with the ring-core method.
How Does It Work?
The technique is based on linear elastic theory and consists of machining a circular groove containing a strain gage. The change in strain resulting from relieving the stressed material is recorded at varying core depths.
Features:
It’s technique is similar to the hole-drill method but has a higher sensitivity than the hole drilling method and can measure larger residual stresses up to the yield strength of the material.
The core that is machined using the ring-core method is larger in size compared to the hole introduced with the hole-drill method.
Other features include:
- Measures residual stresses in all directions in the plane of the part surface
- Maximum measurement depth of 0.25 in. (6 mm)



How are Lambda’s services superior?
Lambda is a recognized leader in the field of residual stress measurement, with extensive experience
testing all types of materials, including metallics, ceramics, and polymers of nearly any shape and size.
- We can test components in our laboratory or in the field
- All residual stress measurements are performed by our certified residual stress engineers and technicians
- Lambda does not subcontract residual stress testing to a third party
Questions about the ring-core technique or other residual stress measurement needs?
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