Apparatus and method for non-destructive testing of materials

Abstract

A device for testing a test material for defects within the test material has an acoustic broadband transducer offset from the test material surface during testing by a distance so that the transducer acquires acoustic waves across an air gap from the test material, wherein the acoustic waves arise from impact of an impact member on the test material.

What is claimed is: 
     
         1 . A device for testing a test material for defects within the test material, the device comprising:
 a housing;   an acoustic broadband transducer housed by the housing;   a plurality of bolsters extending from the housing so that distal ends of the bolsters define a planar surface that is offset from a receiving portion of the acoustic broadband transducer and so that the distal ends are unconnected to each other within the surface;   an impact member defining an impact portion and being housed by the housing so that the impact portion is movable from a retracted position to the surface, wherein the surface is offset from the receiving portion of the acoustic broadband transducer by a distance at which the acoustic broadband transducer is capable of acquiring acoustic waves across an air gap from a test material at the surface, wherein the acoustic waves arise from impact of the impact portion of the impact member with the test material upon movement of the impact portion of the impact member to the surface; and   a processor system in communication with the impact member and the acoustic broadband transducer so that the processor system, in response to receipt of an actuation signal, actuates the impact member to drive the impact portion from the retracted position to the surface and so that the processor system receives a first output signal from the acoustic broadband transducer corresponding to the acoustic waves that arise from impact of the impact portion with a test material at the surface.   
     
     
         2 . The device as in  claim 1 , wherein, between any two of the distal ends, the surface is unobstructed by any structure attached to the housing. 
     
     
         3 . The device as in  claim 1 , wherein the bolsters include respective roller bearings at the distal ends. 
     
     
         4 . The device as in  claim 1 , wherein the processor system is configured to compare a magnitude level of the first output signal to a predetermined level corresponding to possible existence of a defect in the test material. 
     
     
         5 . The device as in  claim 4 , wherein the processor system is configured to determine possible presence or absence of the defect based upon comparison of the magnitude of the first output signal to the predetermined level. 
     
     
         6 . The device as in  claim 5 , further comprising a display in communication with the processor. 
     
     
         7 . The device as in  claim 6 , wherein the processor is configured to control the display to indicate the possible presence or absence of the defect. 
     
     
         8 . The device as in  claim 1 , wherein respective said distal ends define an area within the surface having a first dimension and a second dimension orthogonal to the first dimension, and wherein the first dimension is about 0.44 inches and the second dimension is about two inches. 
     
     
         9 . The device as in  claim 1 , further comprising a data port secured in the housing and in communication with the processor system, wherein the data port is disposed on a surface of the housing transverse to the surface defined by the distal ends of the bolsters. 
     
     
         10 . The device as in  claim 1 , wherein the processor system is configured to respond to receipt of the actuation signal to actuate the impact member to repeatedly drive the impact portion from the retracted position to the surface. 
     
     
         11 . The device as in  claim 1 , wherein the processor system is configured to respond to receipt of the actuation signal to actuate the impact portion to repeatedly drive the impact end from the retracted position to the surface at a rate of at least about eight cycles per second. 
     
     
         12 . The device as in  claim 11 , wherein the processor system is configured to respond to receipt of the actuation signal to actuate the impact device to repeatedly drive the impact portion from the retracted position to the surface at a rate within a range of about eight cycles per second to about ten cycles per second. 
     
     
         13 . The device as in  claim 1 , wherein the acoustic broadband transducer is an electronic condenser transducer. 
     
     
         14 . The device as in  claim 1 , comprising a microphone that contains the acoustic broadband transducer and wherein a system comprising the processor system and the microphone has a resolution of about 0.125 inches in a plane perpendicular to a direction of travel of mechanical waves generated by the impact member in the test material. 
     
     
         15 . The device as in  claim 13 , comprising a microphone that contains the acoustic broadband transducer and wherein a system comprising the processor system and the microphone has a resolution of about 0.125 inches in a plane perpendicular to a direction of travel of mechanical waves generated by the impact member in the test material. 
     
     
         16 . A method for testing a test material for defects within the test material, comprising the steps of:
 providing a test device comprising   a housing,   an acoustic broadband transducer housed by the housing,   a plurality of bolsters extending from the housing so that distal ends of the bolsters define a planar surface that is offset from a receiving portion of the acoustic broadband transducer and so that the distal ends are unconnected to each other within the surface,   an impact member defining an impact portion and being housed by the housing so that the impact is movable from a retracted position to the surface, wherein the surface is offset from the receiving portion of the acoustic broadband transducer by a distance;   placing the test device so that the distal ends engage a test material at the surface;   moving the impact portion of the impact member to the surface so that the impact portion of the impact member impacts the test material; and   acquiring, via the acoustic broadband transducer, acoustic waves across an air gap from the test material, where the acoustic waves arise from impact of the impact portion of the impact member with the test material.   
     
     
         17 . The method as in  claim 16 , further comprising determining possible existence of a defect in the test material in response to information provided acquired from the acoustic broadband transducer corresponding to the acoustic waves acquired at the acquiring step. 
     
     
         18 . The method as in  claim 17 , wherein the determining step comprises comparing a magnitude level of an output signal from the acoustic broadband transducer corresponding to the acoustic waves to a predetermined level corresponding to possible existence of a defect in the test material. 
     
     
         19 . The method as in  claim 16 , wherein the moving step comprises repeatedly driving the impact portion from the retracted position to the surface. 
     
     
         20 . The method as in  claim 16 , wherein the moving step comprises repeatedly driving the impact portion from the retracted position to the surface at a rate of at least about eight cycles per second. 
     
     
         21 . The method as in  claim 16 , wherein the moving step comprises repeatedly driving the impact portion from the retracted position to the surface at a rate within a range of about eight cycles per second to about ten cycles per second.