Elastic Interaction

1
Self-loosening of Threaded Fasteners Due to
Cyclic Transverse Load
Dr. Sayed NassarBasil Housari

• Objectives
• Create a mathematical model to explain the
  self-loosening
• Investigate the effect of different variables on
  the self-loosening
• Create empirical equations and design guidelines
  to avoid the self-loosening

Studied Variables

• Fine vs. coarse
• Hole clearance
• Joint material
• Grip length
• Thread fit

• Frequency of excitation
• Transverse load level
• Initial preload level
• Bolt nut material
• Underhead friction
• Thread friction

10 Hz
Self-loosening Test Set Up