Studies on the fabrication and contact stiffness of mechanical interfaces with tailored rough and structured surfaces

Perris, Jack Alan Nathaniel (2023) Studies on the fabrication and contact stiffness of mechanical interfaces with tailored rough and structured surfaces. PhD thesis, University of Glasgow.

Abstract

Contact stiffness is a measure of how interface separation displacement will respond to an applied load. Contact stiffness is most directly affected by interface geometry, material properties, and external factors such as loading, lubrication etc. Surface geometry is often considered in terms of roughness, the asperities that make up a surface and the compliance they introduce to an interface. The compliance or contact stiffness of an interface has an inherent contribution to how mechanical systems operate. This becomes critically important to engineering design where performance is directly linked to interfacial properties, through individual components or a systemic effect – vibrational response machines, biomedical joints, frictional contacts in turbine and engines. If an engineer can control the contact stiffness of an interface, then there is an opportunity to manipulate the performance of a design to suit the needs of the user.

The work in this thesis explores the viability of creating both controlled, tailored, and repeatable pre-defined microstructured and rough surface topographies. The first half of the work involved the development of a novel fabrication technique that combines microfabrication techniques and manufacturing technologies to generate microstructured topographies in functional polymers with the aim of controlling contact stiffness. The designs were initially modelled in finite element software before manufacture and mechanical testing. The microstructured interfaces yielded promising results that indicate high repeatability and tailoring of contact stiffness to the users’ defined characteristics. The second half introduces the concept of manipulating numerically generated rough surface topographies to be produced in various polymers, again aiming to control contact stiffness. The numerically generated topographies were 3D printed before being replicated in various polymer materials through injection moulding and polymer casting, and finally mechanically tested. The results display a high level of control of surface characteristics which can be translated into the rough surface interfaces. The designs can then be manipulated to achieve the desired contact stiffness properties in a repeatable and tailored fashion. All areas of the work presented in this thesis have the potential to further tribological knowledge and future applications in a wide range of engineering fields.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: T Technology > TJ Mechanical engineering and machinery
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Mulvihill, Dr. Daniel, Gadegaard, Professor Nikolaj and Kartal, Dr. Mehmet
• Date of Award: 2023
• Depositing User: Theses Team
• Unique ID: glathesis:2023-83552
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 24 Apr 2023 09:56
• Last Modified: 24 Apr 2023 09:57
• Thesis DOI: 10.5525/gla.thesis.83552
• URI: https://theses.gla.ac.uk/id/eprint/83552

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