Patent ID: 6839640
Filing Date: 2005-01-04
Classification: B21J,G01N

Abstract:
1. A method of diagnosing a condition of a piled up structure of conductive materials piled up with a non-conductive interface interposed therebetween and fastened together with a fastening member, said method comprising the steps of: placing an electro-magnetic acoustic transducer out of contact with the piled up structure; transmitting ultrasonic waves capable of passing through the non-conductive interface from one side of said piled up structure by said electro-magnetic acoustic transducer; receiving ultrasonic waves reflected from the other side of the piled up structure by said electro-magnetic acoustic transducer; and diagnosing fastening force of the fastening member of said piled up structure on a basis of changes in an ultrasonic velocity and attenuation of the ultrasonic waves received.