Investigation into the Effect of Bonding Methods for 3D Printed Titanium in Scarf Ribbon Repairs with a Composite Parent

Wall, Nicholas (2020) Investigation into the Effect of Bonding Methods for 3D Printed Titanium in Scarf Ribbon Repairs with a Composite Parent. [USQ Project]

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As material technology has continued improving, creating materials that are lighter, stronger, and more resistant to environmental conditions, their prevalence in all industries has also increased. This is no truer than in aviation which has gradually transitioned to polymer composites in order to minimise weight and consequently create some of the most advance transportation and weapons systems ever seen. The use of these materials is not without drawbacks, these mainly being cost, and the complex nature of failure and subsequent repair required. Because of these major factors, research into repair methods has come to the forefront of the industry with emphasis placed on the minimisation of costs associated with the repair processes as well as down-time experienced by the aircraft. The most dominant method used in such repair methods are scarf repair joints which are prepared in an autoclave system. In order to explore more portable and fast paced solutions, out-of-autoclave processes have become the main focus of repair techniques for research. The aim of this study was to identify associated effects and subsequent quality of bond created using the single vacuum bag debulking variant of out-of-autoclave processes utilising a set of basic testing criteria and comparable data taken from the literature.

Using appropriate sample preparation techniques, cure cycle selection and pre-experiment inspection, initial bond quality predictions were established based on visible porosity content and bond line observations. It was observed that cure cycle selection was definitively adequate for the double adhesive thickness samples while the results provide no clear indication of the adequacy for single adhesive samples. The double film adhesive honeycomb lattice scarf performed to the highest standard mechanically producing tensile strengths of 161.8 +/- 15.0 MPa, however displayed high levels of porosity (between 3% - 4%) which is not conducive to bond consolidation. Upon comparison to double vacuum bag debulking techniques, evidence suggested the quality of bond produced by the SVD system was of lower quality with regard to both porosity and resulting failure strength. The final observation was the thermal effect on the failure behaviour evident in the DIC videos taken of the failure event. These observations suggested evidence of a discontinuity caused by a mismatch in thermal properties of the materials.

Further studies into the reduction of porosity utilising DVD systems for dissimilar materials is required in order to establish a clear trend between porosity and resulting repair strength. An investigation into the catering of cure cycle for specific adhesive thicknesses as well as further mechanical testing would benefit the development of repair procedures specifically utilising SVD systems and offer insight into their suitability within the wider industry.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 - 31 Dec 2021)
Supervisors: Zeng, Xuesen
Qualification: Bachelor of Engineering (Honours) (Mechanical)
Date Deposited: 11 Aug 2021 05:46
Last Modified: 26 Jun 2023 04:54

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