US Patent 7730784 Ultrasonic method to verify the interference fit of fasteners

Embodiments of techniques to verify the interference fit of fasteners are disclosed. In one embodiment, a method includes aligning a probe proximate a fastener, the fastener being disposed within a material. A dynamic stress signal is generated from the probe using a low frequency transducer, and the dynamic stress signal is interrogated after it passes between the fastener and the material. An interference fit is then determined based on the interrogated dynamic stress signal.