Health monitoring of joints using dynamic end effects

An experimental feasibility study for monitoring integrity of structural joints, based on measurement of end effects, is reported. The methodology is based on end effects excited when edge conditions deviate from baseline boundary data. It was found that by attaching standard strain gauges to a beam at the immediate vicinity of the joint, it is possible to identify small changes in the clamping condition, either by static loading or by dynamic excitation of the structure. End effects measured on the surface are viewed as the joint health signature. High sensitivity of surface strains to small changes in end conditions can be utilized in structural health monitoring systems to identify low levels of damage for structural joints (realized either by screws, welding, riveting, or bonding).