Conformable acoustic coupler

Abstract

A conformable acoustic coupler for ultrasonically testing an article. The upler has an ultrasonic transducer with an active surface which transmits ultrasonic energy pulses to an article to be tested. A sensor receives and measures an ultrasonic echo from the tested article. The article to be tested is acoustically mated to the active surface by a medium of a gelatinous material layer on the active surface and a flexible film on the gelatinous material layer. The combination of the gelatinous material and film conforms to the shape of the article and provide acoustic coupling between the active surface and the article without leaving a residue of the medium on the article.

What is claimed is: 
     
       1. A conformable acoustic coupler for ultrasonically testing an article, said coupler comprising: a) an ultrasonic transducer having an active surface, which surface is capable of transmitting an ultrasonic energy pulse therethrough, said transducer comprising ultrasonic pulse generating means capable of applying an ultrasonic energy pulse by said active surface to an article; and ultrasonic sensor means capable of receiving and measuring an ultrasonic echo from said article in response to said applied ultrasonic energy pulse; and   b) means for acoustically mating said article to the active surface of said transducer, said acoustic mating means comprising a layer of a gelatinous material on said active surface and a flexible film on said gelatinous material layer, which film substantially does not react with and substantially does not absorb said gelatinous material; wherein said acoustic mating means is capable of conforming to the shape of at least part said article.   
     
     
       2. The coupler of claim 1 wherein said flexible film comprises a material selected from the group consisting of polyvinylidene chloride, polyvinylidene fluoride, polyethylene, and polyethylene terephthalate. 
     
     
       3. The coupler of claim 1 wherein said flexible film has a thickness of from about 0.5 to about 1.0 mil. 
     
     
       4. The coupler of claim 1 wherein said gelatinous material layer comprises a material selected from the group consisting of petroleum jelly, silicone grease, water based jellies and food gels. 
     
     
       5. The coupler of claim 1 wherein said gelatinous material layer has a thickness of from about 0.125 to about 0.25 inch. 
     
     
       6. The coupler of claim 1 wherein said transducer comprises a piezoelectric crystal. 
     
     
       7. The coupler of claim 1 wherein said transducer generates an ultrasonic energy pulse having a frequency in the range of more than 0 to about 104 kHz. 
     
     
       8. A method for ultrasonically testing an article comprising the steps of: i) providing an acoustic coupler, said acoustic coupler comprising: a) an ultrasonic transducer having an active surface, which surface is capable of transmitting an ultrasonic energy pulse therethrough, said transducer comprising ultrasonic pulse generating means capable of applying an ultrasonic energy pulse by said active surface to an article; and ultrasonic sensor means capable of receiving and measuring an ultrasonic echo produced by said article in response to said applied ultrasonic energy pulse; and   b) means for acoustically mating said article to the active surface of said transducer, said acoustic mating means comprising a layer of a gelatinous material on said active surface and a flexible film on said gelatinous material layer, which film substantially does not react with and substantially does not absorb said gelatinous material; wherein said acoustic mating means is capable of conforming to the shape of at least part said article; and     ii) juxtapositioning an article to be tested with said acoustic mating means such that said acoustic mating means conforms to the shape of at least part of said article; and iii) applying an ultrasonic energy pulse to said article through said active surface and said acoustic mating means; and   iv) receiving and measuring the ultrasonic echo produced by said article in response to said applied ultrasonic energy pulse.     
     
     
       9. The method of claim 8 wherein said flexible film comprises a material selected from the group consisting of polyvinylidene chloride, polyvinylidene fluoride, polyethylene, and polyethylene terephthalate. 
     
     
       10. The method of claim 8 wherein said flexible film has a thickness of from about 0.5 to about 1.0 mil. 
     
     
       11. The method of claim 8 wherein said gelatinous material layer comprises a material selected from the group consisting of petroleum jelly, silicone grease, water based jellies and food gels. 
     
     
       12. The method of claim 8 wherein said gelatinous material layer has a thickness of from about 0.125 to about 0.25 inch. 
     
     
       13. The method of claim 8 wherein said transducer comprises a piezoelectric crystal. 
     
     
       14. The method of claim 10 wherein said transducer generates an ultrasonic energy pulse has a frequency in the range of more than 0 to about 104 kHz. 
     
     
       15. A method for ultrasonically testing a munitions article comprising the steps of: i) providing an acoustic coupler, said acoustic coupler comprising: a) an ultrasonic transducer having an active surface, which surface is capable of transmitting an ultrasonic energy pulse therethrough, said transducer comprising ultrasonic pulse generating means capable of applying an ultrasonic energy pulse by said active surface to a munitions article; and ultrasonic sensor means capable of receiving and measuring an ultrasonic echo produced by said munitions article in response to said applied ultrasonic energy pulse; and   b) means for acoustically mating said munitions article to the active surface of said transducer, said acoustic mating means comprising a layer of a gelatinous material on said active surface and a flexible film on said gelatinous material layer, which film substantially does not react with and substantially does not absorb said gelatinous material; wherein said acoustic mating means is capable of conforming to the shape of at least part said munitions article; and     ii) juxtapositioning a munitions article to be tested with said acoustic mating means such that said acoustic mating means conforms to the shape of at least part of said munitions article; and   iii) applying an ultrasonic energy pulse to said munitions article through said active surface and said acoustic mating means; and   iv) receiving and measuring the ultrasonic echo produced by said munitions article in response to said applied ultrasonic energy pulse.   
     
     
       16. The method of claim 15 wherein said flexible film comprises a material selected from the group consisting of polyvinylidene chloride, polyvinylidene fluoride, polyethylene, and polyethylene terephthalate. 
     
     
       17. The method of claim 15 wherein said flexible film has a thickness of from about 0.5 to about 1.0 mil. 
     
     
       18. The method of claim 15 wherein said gelatinous material layer comprises a material selected from the group consisting of petroleum jelly, silicone grease, water based jellies and food gels. 
     
     
       19. The method of claim 15 wherein said gelatinous material layer has a thickness of from about 0.125 to about 0.25 inch. 
     
     
       20. The method of claim 15 wherein said transducer comprises a piezoelectric crystal. 
     
     
       21. The method of claim 15 wherein said transducer generates an ultrasonic energy pulse having a frequency in the range of more than 0 to about 104 kHz. 
     
     
       22. The method of claim 15 wherein said munitions article comprises an artillery shell. 
     
     
       23. The method of claim 15 wherein said munitions article comprises a chemical warfare agent. 
     
     
       24. The method of claim 22 wherein said munitions article comprises a chemical warfare agent.