Mechanical Systems: Friction and Bolted Assemblies

This lecture covers fundamental concepts in mechanical systems, focusing on friction laws, particularly Coulomb's laws, and their applications in engineering. The instructor begins with a summary of the previous week's topics, including static and dynamic friction coefficients. The lecture emphasizes the importance of understanding elastic material mechanics, including stress-strain relationships and the application of Hooke's law. The instructor discusses the behavior of materials under simple and multiaxial stress conditions, introducing rheological models, particularly spring models. The second part of the lecture transitions to bolted assemblies, detailing the principles of bolted connections, the role of thread functions, and the significance of preloading. The instructor explains how to calculate the necessary torque to achieve desired tension in bolts, considering friction at the contact surfaces. The lecture concludes with practical applications and exercises related to bolted assemblies, reinforcing the theoretical concepts presented throughout the session.