Analysis and Optimization of the Deep-Hole Drilling Technique in Measuring Complex Residual Stress

2017 ◽  
Author(s):  
Gang Zheng ◽  
Sayeed Hossain ◽  
Feng Shen ◽  
Chris Truman
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Longitudinal Axis ◽  
Hole Drilling ◽  
Internal Diameter ◽  
Deep Hole ◽  
Element Analysis ◽  
Deep Hole Drilling ◽  
Drilling Technique ◽  
Technique Comparison

The aim of the present study was to utilize a complex residual stress generated within a welded circular disc to further investigate the standard deep-hole drilling (DHD) technique and the newly developed over-coring deep-hole drilling (oDHD) technique in accurately measuring residual stresses well over yield stress. Finite Element Analysis (FEA) was used to optimize and extend the deep-hole drilling technique and improve its accuracy. The standard DHD procedure involves 4 steps. (1) A reference hole is gun-drilled through the component. (2) The internal diameter of the reference hole is measured at different angular positions through the depth of the component. (3) A cylindrical section with the reference hole as its longitudinal axis is trepanned free from the component. (4) Finally, the relaxed internal diameter is re-measured at the same angular positions and the same depths. The drilling, trepanning procedures and the parameters of the deep-hole drilling technique were all studied in detail to optimize the technique. Comparison is made between the FEA predicted residual stress in the weld, the measurements and the reconstructed residual stresses of the measurements. The close correlations confirmed the suitability of new modifications made in the deep-hole drilling technique to account for plasticity when measuring near yield residual stresses present in a component.

Application of the Modified Deep Hole Drilling Technique (iDHD) for Measuring Near Yield Non-Axisymmetric Residual Stresses

2009 ◽  
Author(s):  
Amir-Hossein Mahmoudi ◽  
David J. Smith ◽  
Chris E. Truman ◽  
Martyn J. Pavier
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Fields ◽  
Hole Drilling ◽  
Deep Hole ◽  
Axisymmetric Stress ◽  
Deep Hole Drilling ◽  
Element Simulation ◽  
Drilling Technique ◽  
Shrink Fit

The modified deep hole drilling technique (iDHD) has been developed to allow near yield residual stresses to be measured and has been validated for axisymmetric residual stress fields. In the present investigation, the application of the iDHD technique was extended to non-axisymmetric stress fields. First, a finite element simulation of the iDHD technique was carried out to demonstrate its effectiveness at measuring near yield residual stress. Experimental measurements were then carried out on shrink fit specimens to investigate the performance of the technique in practice. These shrink fit specimens were assembled in such a way that either axisymmetric or non-axisymmetric stress fields could be generated. The results indicated that the iDHD technique is capable of measuring non-axisymmetric residual stresses in presence of plasticity.

Measurement of Residual Stresses in Large Industrial Components Using the Deep Hole Drilling Technique

2005 ◽  
Author(s):  
X. Ficquet ◽  
C. E. Truman ◽  
D. J. Smith ◽  
T. B. Brown ◽  
T. A. Dauda
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Excellent Agreement ◽  
Stress Component ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Drilling Technique ◽  
Compressive Residual Stresses

“ELIXIR – Extending Plant Life Through Improved Fabrication and Advanced Repair Methodology” was a European Union FP5 sponsored project. During the duration of the Elixir project, much work was directed at providing the necessary data for the validation of numerical modelling techniques applied to residual stress generation and hydrogen diffusion arising from the welding process. The project focussed around four industrial applications, namely petrochemical, boiler, offshore and submarine. This paper presents through-thickness residual stress measurements obtained by the University of Bristol on two of the large industrial components. The results were obtained using the deep hole drilling technique and compared to Finite Element predictions provided by other partners. The components considered are a large P275 steel set-in nozzle, typical of a boiler application and a large S690 steel set-on nozzle, typical of an offshore application. The boiler application consisted of a nozzle of diameter 600mm and thickness 50mm, on a pipe of diameter 1100mm and 100mm thickness. The offshore application was a nozzle of diameter 900mm and thickness 50mm, on a pipe of diameter 1050mm and 50mm thickness. Both the longitudinal and transverse stresses measured using deep hole drilling showed excellent agreement with Finite Element predictions through the thickness of the boiler sample. On the top surface, a zone of tensile residual stresses, over a distance of approximately 40mm, was revealed, which was equilibrated by a zone of compressive residual stresses over the final 50mm of thickness. Results for the offshore application demonstrated that at the front surface, both of the stress components were essentially zero, but both the longitudinal and transverse components rose rapidly to maxima of approximately 500MPa and 220MPa, respectively. Tensile residual stresses were supported over a distance of approximately 30mm. Over the final 20mm of thickness, compressive residual stresses existed, which again fell to approximately zero on the back face. There is excellent agreement between measurements and the Finite Element predictions for the transverse stress component, but less good agreement between measurements and predictions of the longitudinal stress component.

A Procedure to Measure Biaxial Near Yield Residual Stresses Using the Deep Hole Drilling Technique

2013 ◽  
Vol 53 (7) ◽  
pp. 1223-1231 ◽  
Author(s):  
A. H. Mahmoudi ◽  
G. Zheng ◽  
D. J. Smith ◽  
C. E. Truman ◽  
M. J. Pavier
Keyword(s):  
Residual Stresses ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Drilling Technique

Effect of Gauge Volume on the Residual Stress Measurement Using Deep Hole Drilling Technique

2010 ◽  
Author(s):  
Amir H. Mahmoudi ◽  
David J. Smith ◽  
Chris E. Truman ◽  
Martyn J. Pavier
Keyword(s):  
Residual Stress ◽  
Material Removal ◽  
Stress Measurement ◽  
Measurement Techniques ◽  
Residual Stress Measurement ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Gauge Volume ◽  
Drilling Technique

Accurate evaluation of residual stress is essential if is to be taken into account in structural integrity assessments. For thick components, many non-destructive residual stress measurement techniques cannot be used since they are unable to measure the stresses deep within the component. Measurement techniques which involve mechanical strain relief through material removal are the only alternative. Recently, it has been found that these techniques may fail to measure the stresses correctly when highly triaxial stresses are present because plastic redistribution can occur when the material removal is carried out. The Deep Hole Drilling technique is a very powerful method to measure the stresses within very thick engineering components. However, it can suffer from high levels of plasticity and lead to inaccurate results. It is shown in the present research that the effect of plasticity on the measured stresses can be eliminated. In the present work, the effect of gauge volume on the plasticity effect is investigated.

Evaluating Uncertainty in Residual Stress Measured Using the Deep-Hole Drilling Technique

Strain ◽  
2011 ◽  
Vol 47 (1) ◽  
pp. 62-74 ◽  
Author(s):  
D. M. Goudar ◽  
C. E. Truman ◽  
D. J. Smith
Keyword(s):  
Residual Stress ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Drilling Technique

Simulation and Measurement of Through–Wall Residual Stresses in a Structural Weld Overlaid Pressurizer Nozzle

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Stephen Marlette ◽  
Paula Freyer ◽  
Michael Smith ◽  
Andrew Goodfellow ◽  
Xavier Pitoiset ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Hole Drilling ◽  
Steel Weld ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Dissimilar Metal ◽  
Stainless Steel Weld ◽  
Stress Profiles

Full structural weld overlays (FSWOLs) have been used extensively as a repair/mitigation technique for primary water stress corrosion cracking in pressurizer nozzle dissimilar metal (DM) welds. To support an approved FSWOL design and safety submission for British Energy pressurized water reactor (PWR) nozzles, an in-depth evaluation was performed to assess the effects of a FSWOL on the through wall residual stress distribution in safety/relief pressurizer nozzles. Two safety/relief pressurizer nozzle mockups were fabricated based on British Energy’s PWR nozzle design. One mockup included the nozzle to safe-end DM weld and the safe-end to stainless steel weld, while the second mockup included the DM weld, the stainless steel weld, and a Westinghouse designed structural weld overlay. The mockups were fabricated utilizing materials and techniques that represented the plant specific nozzles as closely as possible and detailed welding parameters were recorded during fabrication. All welds were subsequently nondestructively evaluated (NDE). A thorough review of the detailed fabrication records and the NDE results was performed and several circumferential positions were selected on each mockup for subsequent residual stress measurement. The through wall residual stress profiles were experimentally measured through the DM weld centerline at the selected circumferential positions using both the deep-hole drilling (DHD) and incremental deep-hole drilling (iDHD) measurement techniques. In addition to experimental residual stress measurements, the through-wall residual stress profiles were simulated using a 2D axisymmetric ansys™ finite element (FE) model. The model utilized the application of temperature constraints on the weld elements to simulate the thermal welding cycle which greatly simplified the simulation as compared with detailed heat source modeling methods. Kinematic strain hardening was used for material modeling of the weld and base metals. A range of residual weld stress profiles was calculated by varying the time at which the temperature constraints were applied to the model. The simulation results were compared with the measurement results. It was found that the effects of the FSWOL were principally threefold. Specifically, the FSWOL causes a much deeper compressive stress field, i.e., the overlay shifts tension out toward the outside diameter (OD) surface. Furthermore, the FSWOL reduces tension in the underlying dissimilar metal weld, and finally, the FSWOL causes higher peak compressive and tensile residual stresses, both of which move deeper into the nozzle wall after the overlay is applied. Relatively good agreement was observed between the FE results and the measurements results.

A New Procedure to Measure Near Yield Residual Stresses Using the Deep Hole Drilling Technique

2008 ◽  
Vol 49 (4) ◽  
pp. 595-604 ◽  
Author(s):  
A. H. Mahmoudi ◽  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
M. J. Pavier
Keyword(s):  
Residual Stresses ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Drilling Technique
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