Identifying Structural Defect Geometric Features From Acoustic Emission Waveforms
AssigneeUniversity of South Carolina
InventorsVictor Giurgiutiu, Jingjing Bao, Banibrata Poddar, Md Yeasin Bhuiyan
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Abstract
The current disclosure determines if structural faults exist and extracts geometric features of the structural faults from acoustic emission waveforms, such as crack length and orientation, and can evaluate the structural faults online, during normal operation conditions.
Claims19
A method for identifying features of a fatigue crack, comprising:
- analyzing emission waves from a fatigue crack;
- applying external excitation to the fatigue crack;
- capturing at least one echo emanating from the fatigue crack caused by the external excitation;
- generating at least one secondary emission wave that emanates from the fatigue crack;
- analyzing amplitude and frequency of the at least one secondary emission wave;
- and
- establishing an initial fatigue crack fingerprint for the fatigue crack and comparing the initial fatigue crack fingerprint to a subsequent fatigue crack fingerprint to analyze fatigue crack progression.
The method of 2, further comprising identifying fatigue crack length and crack tip locations as part of the at least one geometric feature.
The method of 2, wherein frequency dependent patterns in polar plots identify the at least one geometric feature of the fatigue crack.
Creating a library of acoustic emission waveforms linked to crack geometric features comprising:
- generating structural vibrations in a test material;
- generating excitation signals and applying same to the test material;
- collecting first acoustic emission signals generated by the test material;
- measuring surface vibration and displacement in the test material;
- obtaining a frequency response of the test material to the excitation signals;
- extracting surface relative displacement to determine multiple candidate frequencies for acoustic wave detection;
- exciting the test material with at least one candidate frequency and collecting at least one second acoustic emission signals from the test material;
- analyzing the at least one second acoustic emission signal to extract at least one signal signature associated with fatigue crack geometric features;
- and
- forming a library of features wherein the at least one signal signature is associated with fatigue crack geometric features;
- and
- establishing an initial fatigue crack fingerprint for the fatigue crack geometric features and comparing the initial fatigue crack fingerprint to a subsequent fatigue crack fingerprint to analyze fatigue crack progression.
The method of claim of 8, wherein the external excitation is created by a mechanical shaker.
A method for ensuring structural integrity comprising:
- receiving acoustic emissions from a structure;
- analyzing the acoustic emissions to determine if structural faults exist in the structure;
- and
- wherein when at least one structural fault exists, establishing an initial structural fault fingerprint for the structural fault and comparing the initial structural fault fingerprint to a subsequent structural fault fingerprint to analyze structural fault progression.
Dependencies are inferred from the claim text.