November 28, 2023

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Sofema Aviation Services (SAS) www.sassofia.com considers the best practices for Analyzing Complex composite structures using Tap Testing techniques.

Introduction

interpreting TAP hammer testing data requires expertise and experience. It involves comparing the data with established standards, reference data, or known defect signatures. Careful consideration of all relevant factors and clear documentation are crucial for accurate and reliable interpretation of TAP hammer testing data.

Important Note: While tap testing is a useful tool, it’s important to remember that it’s a qualitative method and may not detect all defects, particularly those that are small or deep within the structure.

  • Therefore, it should be used as part of a comprehensive inspection program that includes other non-destructive testing methods.
  • TAP testing is most effective when used in conjunction with other non-destructive testing (NDT) methods. Consider integrating it with techniques such as ultrasonic testing, thermography, or X-ray inspection to obtain a more comprehensive evaluation of the composite structure.

General Guidance Notes

  • Take care to set up properly, including ensuring the sample is securely supported, and the testing surface is clean and free from contaminants. Proper surface preparation helps in obtaining accurate and reliable results.
  • Reference data collected from similar materials or structures can be valuable in interpreting TAP hammer testing results. This data can provide insights into the expected response of the material under normal conditions.

Considering Complex Composite Structure

It is important to note that these examples are intended to illustrate the concept of structural complexity in aviation components. The actual complexity and specific testing requirements may vary depending on the design and materials used in real-world aviation components

  • Aircraft wings often consist of complex composite structures with multiple layers of materials, varying thicknesses, and intricate geometries.

o These structures may have reinforced areas, such as spars and ribs, and different types of composite materials, such as carbon fibre or fiberglass.
o TAP testing for such wing structures would require understanding the limitations and capabilities of the testing method to ensure a thorough inspection of all layers, assess bonding quality, and detect any defects or delaminations.

  • Aircraft fuselages are in some cases manufactured from composite materials, the thickness of these panels may vary to provide structural strength in critical areas while minimizing weight in other sections.

o TAP testing of fuselage panels with varying thicknesses would involve adjusting the testing approach to account for the different material thicknesses and ensure complete inspection of the panels, including the detection of hidden defects or disbonding between layers.

  • Engine nacelles are typically constructed using complex composite materials which can have multiple layers and intricate geometries to accommodate engine components and provide aerodynamic efficiency.

o TAP testing of composite engine nacelle structures would require careful consideration of the testing approach to ensure that all layers and critical areas, such as attachment points and access panels, are thoroughly inspected for defects, disbonding, or damage that could affect the structural integrity.

Interpretation and Analysis

The data obtained from the test reflects the stiffness, density, and integrity of the material being tested. It is important to have a clear understanding of the principles and limitations of this testing method before interpreting the data.

Note: Environmental factors, such as temperature, humidity, and ambient noise, can influence the TAP hammer test results. It is important to account for these factors during the interpretation process. Deviations from the expected response may be attributed to environmental influences rather than material defects. Therefore, understanding and controlling these factors are crucial for accurate interpretation.

Is a crucial step in understanding the condition of a material or structure. It requires expertise and experience to accurately analyze the collected data and draw meaningful conclusions. In this process, several factors should be taken into consideration, such as

  • Comparing the data with established standards, reference data, or known defect signatures.
  • Additionally, consulting industry guidelines, standards
  • Known defect signatures, which are characteristic patterns associated with specific types of defects or damage, can help in identifying and assessing the severity of any observed abnormalities in the data.

Next Steps

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Sofema Aviation Services (www.sassofia.com) offers the following 2-day course – Composite Material TAP Testing for Aviation Inspectors. Please email team@sassofia.com for details.

Tags:

Aircraft, Aircraft defects, Aircraft engine, Aircraft fuselages, Aircraft wings, aviation, Aviation Composite Structures, aviation safety, Complex Composite Structure, Data, EASA, Environmental factors, SAS blogs, Sofema Aviation Services, TAP hammer testing, TAP Testing