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Title: Online monitoring of self pierce riveting systems to provide non-destructive testing of the mechanical interlock
Author: Johnson, Paul John
Awarding Body: Liverpool John Moores University
Current Institution: Liverpool John Moores University
Date of Award: 2013
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The joining of aluminium-bodied cars using self-pierce riveting (SPR) requires non-destructive testing to avoid costly material damage and wastage. SPRjoints are traditionally tested by ultrasonic probing or manual disassembly, both of which are reliant upon to operator skill and opinion. Current real-time monitoring is restricted to the characterisation of a joint by monitoring the setting force and pWlch displacement. Througbout this researcb a variety of image processing techniques have been developed to provide practical nondestructive testing of the joint and surrounding processes to give reat-time decisions regarding the quality of the mechanical interlock. These techniques include examining the rivet status pre-process to ensure the punch slrikes the rivet head correctly, thereby preventing the production of compromised joints through tumbled rivets. The algorithm developed achieves 98% accuracy in detecting the rivet status. Examining the depth of the materials about to be joined ensures that the materials presented are of the expected depth to prevent incorrect triggering, which can cause damage to the joining materials, and/or the riveting machinery. The material measurement algorithm achieves 2% error when measuring 6mm of stacked aluminium. Identifying the relative locations of multiple rivets post-process helps prevent substandard structures by ensuring that the rivets are present and suitably spaced to ensure optimum strength. The algorithm developed achieves 99% accuracy. Each of these techniques provides considerable promise and adds greater confidence when predicting the quality of the mechanical interlock.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available