Coaxial direct-coupled ultrasonic probe and method of non-destructive testing

A probe for detecting defects in a structural material and for actuating a test set to indicate detection of defects, said probe comprising:

• a transmitter contact for physically contacting said material in a transmitter contact region on the surface of said material;
• a transmitter driver means connected to said transmitter contact for mechanically vibrating said transmitter contact so that mechanical vibrations are transmitted into said material;
• a receiver contact for physically contacting said material in a receiver contact region on the surface of said material, said receiver contact region substantially surrounding said transmitter contact region so that mechanical vibrations induced by said transmitter contact in said structural material are intercepted by said receiver contact;
• a receiver transducer means operatively connected to said receiver contact for converting said mechanical vibrations intercepted by said receiver contact into an output electrical signal responsive to defects in said material and for actuating said test set;
• and
• a receiver tube extending between said receiver contact and said receiver transducer means, for transmitting vibrations intercepted by said receiver contact and further for enclosing said transmitter driver means and said receiver transducer means.

An ultrasonic probe for the non-destructive testing of structural materials, said probe comprising:

• a receiver tube having a hollow inner bore and having a separator extending across said bore;
• a transmitter assembly slidably mounted in said bore forward of said separator;
• and
• a receiver transducer operatively connected to said separator inside said receiver tube;
• wherein said separator is located along the length of said receiver tube a distance approximately equal to an odd number of quarter wavelengths of the mechanical vibrations to be detected by said receiver transducer.

An ultrasonic probe for the non-destructive testing of a structural material, said probe comprising:

• a transmitter assembly having a transmitter button for contacting said structural material;
• a receiver having a receiver ring for substantially encircling said transmitter button and for contacting said structural material, and a receiver transducer;
• and
• a receiver tube extending between said receiver ring and said receiver transducer for transmitting vibrations intercepted by said receiver ring and further for enclosing said transmitter assembly and said receiver transducer.

An ultrasonic probe for the non-destructive testing of a structural material, said probe comprising:

• a transmitter assembly for transmitting ultrasonic vibrations into a transmitting surface region of said structural material;
• and
• means for receiving ultrasonic vibrations from a receiving surface region of said structural material, and wherein said receiving surface region substantially surrounds said transmitting surface region;
• wherein said transmitter assembly comprises:
• a transmitter button for contacting said structural material;
• and
• means for vibrating said transmitter button at a frequency on the order of 15 kHz so that said transmitter button can transmit ultrasonic vibrations into said transmitting surface region of said structural material.

An ultrasonic probe for the non-destructive testing of a structural material, said probe comprising:

• means for transmitting ultrasonic vibrations into a transmitting surface region of said structural material;
• means for receiving ultrasonic vibrations from a receiving surface region of said structural material, said means for receiving having an omnidirectional response sensitivity to detect defects in all substantially radial directions outward from said transmitting surface region on the surface of said structural material;
• and
• a means for selectively responding to a preselected vibration frequency, said means for selectively responding having a tuned waveguide selector for enhancing the sensitivity of said means for receiving to ultrasonic vibrations of said preselected vibration frequency.

A method of non-destructive testing of a structural material for use with a contacting ultrasonic probe and a test set, said method comprising the steps of:

• transmitting ultrasonic vibrations into said structural material by said probe in a transmitting surface region of said structural material;
• receiving ultrasonic vibrations from said structural material by said probe in a receiving surface region of said structural material, said step of receiving comprising receiving of ultrasonic vibrations in substantially all radial directions from said transmitting surface region on the surface of said structural material;
• transmitting said received ultrasonic vibration through an air cavity;
• converting the ultrasonic vibrations transmitted through said air cavity into a signal;
• and
• using said signal to signal said test set with the results of said step of receiving so that defects in said structural material may be identified and located.