Experiments On Vibration-Induced Loosening Of Bolts

Report describes experimental study of loosening of bolts in presence of vibrations. Eleven design parameters considered likely to affect tendency to loosen evaluated for relative importance. Parameters were bolt diameter, lubrication on bolt, lubrication on mating materials, bolt-hole tolerance, preload, nut-locking device, grip length, thread pitch, class of fit, joint configuration, and mass of configuration. Bolts tested in vibration for two values of each design parameter.