Composite Component Acoustic Emission Testing for Internal Damage
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Solution Overview
Problem
The challenge in assessing the manufacturing quality and structural integrity of composite materials, particularly in aerospace applications, lies in the difficulty of non-destructively determining material properties and detecting flaws due to variations in lay-up procedures and materials, which are critical for compliance with regulatory standards like FAA requirements, especially when repairs are needed.
Innovation Solution
A method involving acoustic emission testing with sensors and signal generators to induce acoustic events, analyze peak frequency components, and determine laminate parameters, including fiber type and resin type, to non-destructively assess composite materials, capable of detecting internal damage and flaws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acoustic emission testing is used to non-destructively identify composite material properties, then the need for expensive ultimate load testing and facility requirements are reduced, but the complexity of analyzing variations in peak frequency components and determining laminate parameters increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing reference data sets containing peak frequency components corresponding to known laminate parameters (fiber type, resin type, stacking sequence) before actual inspection. During testing, the measured frequency components are compared against these pre-established references to automatically identify material properties, eliminating the need for complex real-time analysis and reducing operational complexity.
Solution Approach 2:
The patent creates copies of known reference signatures (frequency component patterns) for different laminate configurations and stores them in a database. The inspection process involves comparing measured frequency patterns against these stored copies to identify the actual laminate parameters, simplifying the analysis by transforming it into a pattern matching problem rather than a complex interpretation task.
2Measurement precision
If multiple acoustic emission events are induced at multiple predetermined locations to comprehensively assess composite properties, then the accuracy of material identification and flaw detection is improved, but the inspection time and productivity are reduced
Solution Approach 1:
The patent makes the acoustic emission testing system universal by designing it to simultaneously determine multiple laminate parameters (fiber type, resin type, stacking sequence, presence of delaminations) from a single set of frequency component measurements. This multi-functionality allows comprehensive material identification without requiring separate tests for each parameter, thereby maintaining high precision while improving productivity.
Solution Approach 2:
The patent merges multiple measurement objectives into a single integrated testing approach. By inducing acoustic emission events and analyzing the resulting frequency components, the system simultaneously identifies fiber type, resin type, stacking sequence, and detects internal flaws—all in one inspection sequence rather than requiring separate tests for each parameter.
3Difficulty of detecting and measuring
If acoustic emission testing with frequency component analysis is used to detect internal damage and flaws, then the capability to discern internal damage without destruction is improved, but the difficulty of detecting and measuring subtle variations in frequency components increases
Solution Approach 1:
The patent introduces an intermediary reference database that contains pre-measured frequency component patterns for known laminate configurations and damage states. This reference data acts as a mediator between the raw frequency measurements and the final damage assessment, providing a basis for comparison that enhances detection capability while accounting for measurement variations and uncertainties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for reduced facility requirements and maintenance, enabling efficient inspection of composite structures for defects with a single test, discerning internal damage, and verifying structural integrity without destruction, suitable for in-service structures and repairs.
Implementation Method 1
inducing a plurality of acoustic emission events on the composite material at a plurality of predetermined locations relative to a sensor
Data Source
AI summary
This disclosure describes systems, methods, and an apparatus for non-destructively assessing composites. The behavior of propagating elastic waves through a structure can provide significant information on the structure and has thus been studied extensively for development of structural monitoring techniques. In thin plates guided waves can develop, which are inherently dispersive, with highly material dependent dispersion characteristics. The identification of the different parameters within a laminate that may affect their mechanical properties is an important step in the assessment of laminate structures.