Ultrasonic load indicating member

A fastener adapted for measuring longitudinal strain in the fastener, said fastener comprising:

• a shank having a longitudinal axis and a predetermined longitudinal length, said shank being adapted to be subjected to longitudinal strain along said longitudinal axis;
• a head formed at one extreme and of said shank said fastener having a generally flat surface disposed on said head normal to said longitudinal axis;
• first electrode means permanently, mechanically, electrically, and acoustically interconnected with said head;
• piezoelectric film means permanently, mechanically, and electrically interconnected with said first electrode means;
• and second electrode means permanently, mechanically, and electrically interconnected with said piezoelectric means and electrically isolated from said head and said first electrode means;
• such that said electrode and said piezoelectric means cooperate to form an ultrasonic transducer.

A fastener adapted for measuring longitudinal strain in the fastener, said fastener comprises:

• a shank having a longitudinal axis and a predetermined longitudinal length, said shank being adapted to be subjected to longitudinal strain along said longitudinal axis;
• a head formed a one extreme and of said shank, said fastener having a generally flat surface disposed on said head normal to said longitudinal axis;
• a first electrode means permanently, mechanically, electrically, and acoustically interconnected with said head by means of an adhesive;
• a thin piezoelectric film disk permanently, mechanically, and electrically interconnected with said first electrode means;
• second electrode means permanently, mechanically, and electrically interconnected with said piezoelectric film disk and electrically isolated from said head and said first electrode means, such that said electrode means and said piezoelectric film disk cooperated to form an ultrasonic transducer, said first and second electrode means comprising metallic films disposed on opposite faces of said piezoelectric film disk.