Thermo-Mechanical Instabilities in Next-Generation Friction Materials in High-Speed Sliding Systems

<p>For centuries, the manufacturing industry has incorporated metals like copper into friction materials to enhance thermal properties and minimize thermo-mechanical instabilities (TMI) in high-speed sliding systems. Unfortunately, these metals have adverse environmental effects due to the emission of hazardous particulate matter. As a result, there is a growing movement towards adopting next-generation friction materials as an alternative solution.</p> <p>The study begins by conducting experimental and numerical investigations to examine the instabilities found in metal-based friction materials. The primary objective is to utilize the insights gained from the investigations to computationally explore effective strategies for mitigating various instabilities that may arise in next-generation friction materials when used in high-speed systems.</p> <p>To study the instabilities in metallic-based friction materials, a Cu-based friction material was developed. The study analyzed the friction properties and wear rate of this friction material while sliding against 65Mn steel using a Universal Mechanical Tester-5, and investigated the effects of sliding speed and temperature on the engagement process. The results offer valuable information on the relationship between the friction coefficient and wear rate; instabilities and critical sliding speed, as well as the growth rate of hotspots in metallic friction materials.</p> <p>To assess the ability of a carbon fiber-reinforced hybrid composite friction material, which is free of copper, to withstand thermo-mechanical instabilities in sliding materials, a nonlinear transient thermo-mechanical model using Finite Element Code was used. The model was used to identify material properties that significantly affect the onset of TMI and which properties need enhancement for efficient use of the friction material in brakes and clutches.</p> <p>Furthermore, to tackle instabilities like vibration and noise in automotive disc brakes and clutches, a viscoelastic friction material was proposed as another alternative. A mathematical model was developed to examine the instability of this material, by considering three physical material parameters: relaxation time, elasticity, and thermal conductivity. The study provides an intuitive means of predicting the onset of thermo-mechanical instabilities in viscoelastic friction materials and a better understanding of the influence of viscoelastic parameters in sliding systems.</p>

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Year

2023

Author dc:creator

• Koranteng, Kingsford

Contributors dc:contributor

• Yun-Bo Yi
• Mohammad Abdul Matin
• Matt Howard Gordon
• Chadd W. Clary

• Friction materials
• Thermo-mechanical instabilities (TMI)
• High-speed sliding systems
• Engineering
• Materials Science and Engineering
• Mechanical Engineering
• Other Materials Science and Engineering
• Other Mechanical Engineering
• Structural Materials

Statement dc:rights

• <p>Copyright is held by the author. User is responsible for all copyright compliance.</p>

Language dc:language

English (eng)

Repository record dc:identifier

https://digitalcommons.du.edu/etd/2355

OAI identifier oai:identifier

oai:digitalcommons.du.edu:etd-3340