Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508308
Title: The calibration and measurement of residual stresses by the deep hole drilling technique
Author: Su, Bin
ISNI:       0000 0001 2416 9941
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2009
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Abstract:
This research project mainly focuses on the deep-hole drilling (DHD) method. It is a semi-invasive technique that involves drilling a small hole through the component and then the accurate measurement of the reference hole diameter. A cylinder of material containing the hole is then extracted from the component causing the hole to deform due to the relaxation of the residual stresses present. The hole diameter is then re-measured and the measured radial distortions are used to determine the residual stress distribution. The major objective of this project was to undertake development of the DHD technique to increase its validation and accuracy. It demonstrated that the DHD technique was more practical than the other inversion methods. The DHD method was further developed by using a Talysurf to measure the axial strain of the reference core. The new method relies on measurement of surface profiles. The appropriate feed rate during gundrilling was also determined and the incremental DHD technique was developed. Some simple loading systems were designed to introduce uniaxial stress into samples; both linear and non-linear axial stress distributions were measured. The major concern of the method lies in the ability of Talysurf to measure the roughness profiles of the surface resulting from the gundrilling of the hole and determine different axial strains loaded on the sample due to comparison of the changes of the profiles. Also, the development of calibration specimens was carried out. Two techniques were applied to generate controlled residual stresses in specimens: local compression and a shrink fit assembly. A residual stress field as a wave function of known wavelength and magnitude was generated by a novel application of the side punching technique. The results from the FE prediction and the DHD measurement agree well. Finally, the DHD technique was applied to practical engineering components. It demonstrated the validation and accuracy of the DHD technique in practical applications.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.508308  DOI: Not available
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