Methods and apparatus for porosity measurement and defect detection

1. A method for non-destructively inspecting a composite structure with an ultrasonic system including an ultrasonic probe, said method comprising:

calibrating the ultrasonic system on a standard;

positioning the composite structure in a tank-less environment;

scanning the composite structure with an ultrasonic phased array probe of the ultrasonic system to measure ultrasonic sound waves reflected by the composite structure to the ultrasonic phased array probe;

determining a physical characteristic of the composite structure based at least in part on the measured ultrasonic sound waves to generate a digital image showing cross-sectional physical characteristics of the composite structure; and,

utilizing the measured ultrasonic sound waves to determine an attenuation for sound waves reflected by the composite structure; and,

wherein:

said scanning the composite structure comprises scanning the composite structure with the ultrasonic system to measure an ultrasonic amplitude and a frequency for sound waves reflected by the composite structure to the ultrasonic phased array probe; and,

said determining a physical characteristic comprises determining a porosity percentage for the composite structure as a function of the determined attenuation and the measured frequency of the ultrasonic sound waves reflected by the composite structure.

2. A method in accordance with Claim 1 , wherein the sound waves reflected by the composite structure comprise a back reflection from the composite structure.

3. A method in accordance with Claim 1 , wherein said scanning the composite structure comprises scanning the composite structure using a single frequency of sound waves emitted by the ultrasonic probe.

4. A method in accordance with claim 3 , wherein the single frequency is less than about 2 MHz.

5. A method in accordance with Claim 1 , wherein said determining the porosity percentage for the composite structure comprises a linear equation.

6. A method in accordance with Claim 1 , wherein said scanning a composite structure comprises scanning the composite structure with an ultrasonic phased array probe at a frequency of less than about 2 MHz.

7. An apparatus for non-destructively inspecting a composite structure, said apparatus comprising:

an ultrasonic system including:

an ultrasonic phased array probe configured to transmit and receive ultrasonic sound waves in a tankless environment; and,

electronic equipment configured to operate the ultrasonic phased array probe to generate and amplify ultrasonic sound waves; and,

a data collection system including a computer, said data collection system configured to collect ultrasonic information;

said apparatus configured to:

scan the composite structure with the ultrasonic system to measure ultrasonic amplitude and a frequency of ultrasonic sound waves reflected by the composite structure to the ultrasonic phased array probe; and,

determine a porosity percentage of the composite structure based at least in part on the measured ultrasonic sound waves to generate a digital image showing cross-sectional physical characteristics of the composite structure.

8. An apparatus in accordance with claim 7 , wherein the apparatus is configured to calibrate the ultrasonic system on a standard, and utilize the measured ultrasonic sound waves to determine attenuation for sound waves reflected by the composite structure, and wherein

said apparatus is configured to determine the porosity percentage as a function of the determined attenuation and the measured frequency of the ultrasonic sound waves reflected by the composite structure.

9. An apparatus in accordance with claim 8 , wherein said apparatus is configured to measure the ultrasonic amplitude and the frequency of sound waves comprising a back reflection from the composite structure.

10. An apparatus in accordance with claim 8 , wherein the ultrasonic phased array probe emits a single frequency of sound waves.

11. An apparatus in accordance with claim 10 , wherein the single frequency is less than about 2 MHz.

12. An apparatus in accordance with claim 8 , wherein said apparatus is configured to determine the porosity percentage for the composite structure as a function of the determined attenuation and the measured frequency utilizing a linear equation.

13. An apparatus in accordance with claim 8 , further comprising a scanning system configured to position the ultrasonic phased array probe relative to the composite structure to obtain ultrasonic information.

14. An apparatus in accordance with Claim 7 , further comprising a scanning system configured to position said ultrasonic phased array probe relative to the composite structure to obtain ultrasonic information.

15. An apparatus in accordance with claim 14 , wherein said apparatus is configured to:

scan the composite structure with the ultrasonic phased array probe at a plurality of locations of the composite structure to measure a plurality of ultrasonic sound waves reflected by the composite structure to the ultrasonic phased array probe; and,

utilize the measured ultrasonic sound waves to generate a plurality of digital images, each of the plurality of digital images showing cross-sectional physical characteristics of a different one of the plurality of locations of the composite structure.