US-12625021-B1 - Systems and methods for rapid force-based measurements of residual stress

Abstract

Systems and methods that directly measures forces caused by residual stresses in components. The components may be manufactured components including via Additive Manufacturing (AM). The system and method may use a small force sensor fitted onto a part of the component and a force sensor may be placed/fitted near a region of expected residual stress of the component. The tension device may be tensioned to apply a small preload onto the component while a relaxation technique is applied to regions of the component while measuring the load on the force sensor. Regions may be individually and sequentially relaxed by slitting the regions via wire electrical discharge machining (EDM) while measuring the load on the force sensor to directly measure force caused by residual stress within the component.

Inventors

• Dale Cillessen
• Kyle Leslie Johnson

Assignees

• NATIONAL TECHNOLOGY & ENGINEERING SOLUTIONS OF SANDIA, LLC

Dates

Publication Date

20260512

Application Date

20240423

Claims (18)

1. 1 . A method of determining residual stress in a region of a component, including: applying a preload on the component; applying a relaxation technique to the region; and measuring a load on the component while applying the relaxation technique to the region; wherein measuring the load on the component while applying the relaxation technique to the region includes: employing a force sensor in a section of the component where the load on the region of the component is measured; and measuring via the force sensor the load on the component while applying the relaxation technique to the region.
2. 2 . The method of determining residual stress of claim 1 , wherein applying a preload on the component includes employing a tension device to apply a preload on the component.
3. 3 . The method of determining residual stress of claim 2 , wherein measuring the load on the component while applying the relaxation technique to the region includes: employing the force sensor together with the tension device in a section of the component where the load on the region of the component is measured; and measuring via the force sensor the load on the component while applying the relaxation technique to the region.
4. 4 . The method of determining residual stress of claim 3 , wherein the component is manufactured via additive manufacturing to include the section that is sized to receive the force sensor and the tension device, enable the force sensor to measure the load on the region of the component, and enable the tension device to place the load on the component.
5. 5 . The method of determining residual stress of claim 1 , wherein the component is a structural component.
6. 6 . The method of determining residual stress of claim 1 , wherein the component is manufactured.
7. 7 . The method of determining residual stress of claim 1 , wherein the component is manufactured via additive manufacturing.
8. 8 . The method of determining residual stress of claim 1 , wherein the component is manufactured via additive manufacturing to include the section that is sized to receive the force sensor and enable the force sensor to measure the load on the region of the component.
9. 9 . The method of determining residual stress of claim 1 , wherein applying the relaxation technique to the region includes slitting the region via wire electrical discharge machining.
10. 10 . A method of determining residual stress in a plurality of regions of a component, including: applying a preload on the component; sequentially applying a relaxation technique to the plurality of regions; and measuring a load on the component while sequentially applying a relaxation technique to the plurality of regions; wherein measuring the load on the component while sequentially applying a relaxation technique to the plurality of regions includes: employing a force sensor in a section of the component where the load on the plurality of regions of the component is measured; and measuring via the force sensor the load on the component while sequentially applying the relaxation technique to the plurality of regions.
11. 11 . The method of determining residual stress of claim 10 , wherein applying a preload on the component includes employing a tension device to apply a preload on the component.
12. 12 . The method of determining residual stress of claim 11 , wherein measuring the load on the component while sequentially applying the relaxation technique to the plurality of regions includes: employing the force sensor together with the tension device in a section of the component where the load on the plurality of regions of the component is measured; and measuring via the force sensor the load on the component while sequentially applying the relaxation technique to the plurality of regions.
13. 13 . The method of determining residual stress of claim 12 , wherein the component is manufactured via additive manufacturing to include the section that is sized to receive the force sensor and the tension device, enable the force sensor to measure the load on the plurality of regions of the component, and enable the tension device to place the load on the component.
14. 14 . The method of determining residual stress of claim 10 , wherein the component is a structural component.
15. 15 . The method of determining residual stress of claim 10 , wherein the component is manufactured.
16. 16 . The method of determining residual stress of claim 10 , wherein the component is manufactured via additive manufacturing.
17. 17 . The method of determining residual stress of claim 10 , wherein the component is manufactured via additive manufacturing to include the section that is sized to receive the force sensor and enable the force sensor to measure the load on the plurality of regions of the component.
18. 18 . The method of determining residual stress of claim 10 , wherein sequentially applying the relaxation technique to the plurality of regions includes sequentially slitting the plurality of regions via wire electrical discharge machining.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Application No. 63/567,961, filed Mar. 21, 2024, which is incorporated herein by reference. STATEMENT OF GOVERNMENT INTEREST This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. TECHNICAL FIELD The present invention relates to systems and methods for measuring or determining residual stress in a component. BACKGROUND A residual stress field is a self-equilibrating stress field in a body independent of any external forces or tractions. Residual stresses are an elastic response to incompatible local strains within a component, for example, due to non-uniform plastic deformation. These stresses are often the result of manufacturing processes such as forging, rolling, bending, extrusion, machining, and grinding. Residual stresses can also be caused by material phase changes and/or large thermal gradients caused by processes such as welding, quenching, or casting. More recently, residual stresses have received much attention in the field of Additive Manufacturing (AM), which generally describes processes that deposit material in a layer-by-layer fashion. These processes often utilize very localized heat sources, such as lasers, to melt material, which leads to high thermal gradients and high residual stresses. SUMMARY The present disclosure is directed to systems and methods for directly measuring forces caused by residual stresses in components. The components may be manufactured components including via Additive Manufacturing (AM). The system and method may use a small force sensor fitted onto a part of the component. The force sensor may be placed/fitted near a region of expected residual stress of the structural component. The force sensor may be connected to the component via a tension device including machine screws. The tension device may be tensioned to apply a small preload onto the component. A relaxation technique may be applied to regions of the component while measuring the load on the force sensor. The relaxation technique may include layer removal, sectioning, hole-drilling, ring coring, and slitting of regions individually. Regions may be individually and sequentially relaxed by slitting the regions via wire electrical discharge machining (EDM) while measuring the load on the force sensor to directly measure force caused by residual stress within the component. BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate several embodiments of the invention, wherein identical reference numerals refer to identical or similar elements or features in different views or embodiments shown in the drawings. The drawings are not to scale and are intended only to illustrate the elements of various embodiments of the present invention. FIG. 1 is a simplified front diagram of testing architecture for determining residual stresses in regions of a structural component according to various embodiments. FIG. 2A is a simplified isometric diagram of testing architecture for determining residual stresses in regions of a structural component via a wire Electrical Discharge Machining (EDM) according to various embodiments. FIG. 2B is an enlarged diagram of Area AA of testing architecture shown in FIG. 2A according to various embodiments. FIG. 3 is an algorithm for measuring residual stress in regions of a structural component according to various embodiments. FIG. 4 is a graph of force sensor data across a structural component to measure residual stress in regions as they are relaxed according to various embodiments. FIG. 5 is an isometric diagram of structural components as manufactured according to various embodiments. DETAILED DESCRIPTION Residual stresses are independent of external loads and often unknown. They are typically ignored during engineering design and analysis. Sometimes residual stresses can improve performance, such as compressive stresses on the surface of a component from shot peening that can improve fatigue life. Residual stress can also be harmful, such as tensile stresses on the surface of a part put into bending. Residual stresses may also cause distortion during manufacturing that can lead to a part geometry outside of acceptable tolerances. Distortion is a major problem in welding, which can be one of the final steps of manufacturing. The resulting distortion can render a part useless and can lead to increased cost and schedule delays. Distortion is also common when a part is machined because the forces due to stress on the cut surface will be relieved and the forces in the remaining material (due to stress gradients caused by the self-equilibrating nature) will cause the material to move. Accordingly, it is important to determine residual stress in components manufactured or otherwise. Quantifying residual stress may employ relaxa