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PhD Defence Erik de Vries | Friction of biomechanical interfaces

Friction of biomechanical interfaces

The PhD Defence of Erik de Vries will take place in the Waaier building of the University of Twente and can be followed by a live stream.
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Erik de Vries is a researcher in the Department Mechanics of Solids, Surfaces Solids and Systems. Promotors are prof.dr.ir. E. van der Heide and dr. D.T.A. Matthews from the Faculty of Engineering Technology.

In this study, the focus is on the interaction between biological materials, like skin, and non-living materials, particularly in the context of medical implants, prostheses, and orthoses. These interactions are crucial for the functionality and durability of such devices. The type of contact varies depending on whether the device is inside or outside the body.

For internal applications, like knee or hip prostheses, the device interfaces with bone tissue. In some cases, such as replacing a damaged meniscus, the device interacts with joint cartilage. In external devices like orthoses and skin-contacting prostheses, soft liners made of materials like polyurethane or silicone rubber help distribute pressure and minimize skin issues caused by contact pressures and friction.

The thesis explores five distinct contact-related issues:

  1. Lubrication of polyurethane rubber with synthetic synovial fluid, highlighting the importance of proteins in lubrication behavior and differences in friction between plastic and metal surfaces.
  2. Influence of implant roughness in knee prosthesis compression, revealing that bone properties have minimal impact on friction, and numerical analysis accurately predicts friction based on implant roughness.
  3. Micro-displacement in the contact between bone and rough implant surfaces, crucial for implant fixation and revision arthroplasty, showing that bone quality and implant roughness affect limiting displacement and contact stiffness.
  4. Influence of adhesion on skin contact under very low pressures, where surface free energy and tension of skin and fluids significantly impact friction.
  5. The effect of liner roughness on friction during prostheses and orthoses use, emphasizing the role of friction in device functionality and pressure ulcer prevention.

Overall, this study contributes to our understanding of tribological behavior in biomechanical interfaces, providing valuable insights into friction mechanisms in medical devices, ultimately contributing to their effectiveness and longevity.