Acoustic Emission Monitoring During Acceptance Proof Testing of Composite Laminated Pressure Vessels

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dc.contributor.advisor Battley, Mark
dc.contributor.author Su, Andy
dc.date.accessioned 2021-01-12T01:52:51Z
dc.date.available 2021-01-12T01:52:51Z
dc.date.issued 2020 en
dc.identifier.uri https://hdl.handle.net/2292/54180
dc.description Full Text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Rocket Lab are looking to increase production of composite laminated pressure vessels (CLPVs) for greater flight cadence while ensuring reliability. As part of quality assurance, CLPVs must undergo a hydrostat acceptance proof testing. However, passing the proof test does not directly provide any information about manufacturing defects in the CLPV that may reduce its burst pressure. The use of acoustic emission (AE) monitoring concurrently during the hydrostat acceptance proof testing provides an opportunity to identify defects within the CLPV, and provide more quantitaive assessment of part quality. An initial investigation of AE monitoring to understand damage behaviour at the coupon level was conducted. This provided understanding to correlate between damage behaviour and the AE parameter behaviour of CLPVs. The AE behaviour of CLPVs with and without intentionally introduced manufacturing defects were analysed to develop AE based acceptance criteria. The intentionally introduced manufacturing defects were the inclusion of backing paper at critical areas, misalignment in the laminate and poor consolidation of the laminate. AE based acceptance criteria were designed using an envelope defined by the AE hit behaviour for the median, 75% percentile and maximum rise time and energy of non-defect CLPVs at different loading windows when approaching proof pressure. Additionally, a similar acceptance criteria design based on the Felicity ratio was developed. The effectiveness of each acceptance criteria was evaluated against the various defect CLPVs. Unpredictable noise behaviour during AE monitoring and inherent variation of the AE metrics selected for use as AE based acceptance criteria affected its validity when rejecting defect CLPVs. All defect CLPVs passed the existing hydrostat acceptance proof testing despite some defect CLPVs having burst pressures greater than that of non-defect CLPVs. All defect CLPVs reported failure from different combinations of rise time, energy and Felicity ratio based acceptance criteria. The passing or failing of an acceptance criterion could not be correlated to the defect CLPV’s first leak pressure or burst pressure. Further work towards reducing the effect of AE noise and refining acceptance criteria based on AE metrics with less inherent variation is required for more accurate rejection of defect CLPVs.
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA en
dc.rights Restricted Item. Full Text is available to authenticated members of The University of Auckland only. en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.rights.uri http://creativecommons.org/licenses/by-nc-sa/3.0/nz/
dc.title Acoustic Emission Monitoring During Acceptance Proof Testing of Composite Laminated Pressure Vessels
dc.type Thesis en
thesis.degree.discipline Engineering
thesis.degree.grantor The University of Auckland en
thesis.degree.level Masters en
dc.date.updated 2020-12-17T22:08:09Z
dc.rights.holder Copyright: the author en


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