NDE Methods and Capabilities Handbook – Reducing the Development and Certification Timeline for Composite Materials and Structures

Presenting author(s): Ms Patricia A Howell

Co-Authors:

Room: Emerald III | 9:00 AM Wednesday, May 1, 2019

Composite structures are often difficult to inspect due to the anisotropic nature of the material systems and the range of flaws and defects that can arise in the manufacturing process. NASA’s Advanced Composites Project, a public-private partnership between government, universities and industry, seeks to address improved methods, tools, and protocols to reduce the development and certification timeline for composite materials and structures. The rapid inspection of composites is one of the three focused research areas of the project. One deliverable of the project is to develop an NDE Methods and Capabilities Handbook. This Handbook provides a publically available guidance document that facilitates the selection of appropriate NDE techniques and provides recommended protocols for detecting and characterizing common flaw types in solid laminate polymer matrix composite (PMC) structures. The Handbook will reduce the time required to develop qualified inspection processes for composite aircraft structures during the development, certification, and manufacturing phases by providing a reference that helps minimize trial and error and provides guidance on best practices, techniques, and settings, for specific flaw types and geometries. The Handbook will include an NDE Guidance Matrix that provides an applicability rating for NDE techniques as they apply to given flaw types. NDE techniques will include, but is not limited to ultrasound, laser based ultrasound, infrared thermography, and x-ray CT. Flaw types will include, but are not limited to porosity, delamination, voids, AFP defects and impact damage. The Handbook will contain details that support the applicability rating including, but not limited to, specimen details, inspection parameters, data analysis techniques, inspection efficiency (speed & cost), and limitations. This presentation will describe key Handbook activities with examples of the techniques and flaw types examined by the Advanced Composite Consortium members.

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Introduction of USAF Depot NDI Data Fusion Collection Tools to Improve AC Structural Integrity

Presenting author(s): Mr Ward A Fong

Co-Authors:

Room: Emerald III | 9:30 AM Wednesday, May 1, 2019

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Automated and Semi-Automated PAUT Inspection of Composites

Presenting author(s): Mr Borja Lopez

Co-Authors:

Room: Emerald III | 10:30 AM Wednesday, May 1, 2019

This paper compares a camera encoded semi-automated system and an automated robotic system using the same PAUT instrumentation and software. The paper provides information on detection capabilities, inspection speeds, setup, ease-of-use, and investment costs for each solution.

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3D Visualization of Multi-Axis PAUT Probe Scanning: Application to Composite Materials

Presenting author(s): Mr Francois Mainguy

Co-Authors: Mr Francois Lauzon

Room: Emerald III | 11:00 AM Wednesday, May 1, 2019

Phased array scanning of composites is often performed on complex surfaces. The probe is typically moved by a multi-axis robot, or manually operated. When manually operated, the probe position and orientation can be encoded by a CMM arm or a camera system. In all these cases, a multi-axis real-time position is provided along with the ultrasound data, and the aim is to map the data adequately on the complex surface. Several solutions were developed in the last 20 years. A new solution is presented, allowing a very powerful mapping of the 2D and 3D data. A new parallel, collaborative workflow is proposed, running on PC and on portable instrumentation, based on a new 3D visualization engine to improve the clarity and reliability of the inspection.

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Phased-Array UT Inspection-Method Development for Composite-Bonded Pi Joints in Aerospace Components

Presenting author(s): Mr Thomas R Jenkins »

Co-Authors: Mr Bruce A Pellegrino

Room: Emerald III | 11:30 AM Wednesday, May 1, 2019

This paper will cover of development of a phased-array UT technique targeted at improving probability of detection (POD), coverage and inspection productivity of composite bonded Pi joints. It compares three approaches to conquer the practical issues around acoustic coupling with potentially irregular Pi joint surfaces. The approaches will be discussed including actual CIVA 3D modeling, CAD mechanical models of the devices, and the use of 3D printing techniques in the coupling schemes. UT data of actual scanned Pi-Joint components will be covered in the paper.

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Low Cost High Resolution Transient Thermography Imaging Based on Equivalent Wave Field Transform

Presenting author(s): Dr Meir Gershenson

Co-Authors:

Room: Emerald III | 2:00 PM Wednesday, May 1, 2019

Thermal propagation follow diffusion equation. As such interpretation of images isn’t simple. Using equivalent wave field transform one can transform from diffusive propagation into wave field. Interpretation of wave field propagation is well developed field. The application of the transform results in sharper reflections with time delay proportional to the distance. Further improvement in lateral and depth resolution can be achieved by use of back projection commonly used to invert wave data with simple geometry. I have built a prototype unit based on low cost smart phone thermal imager and quartz halogen light bulbs. The system was tested on traditional flat bottom hole test sample of polycarbonate plate and on carbon composite samples. Additional data of composite sample with Teflon inserts was obtained from Opgal. The images are superior to the common techniques in use. Flat bottom hole with aspect ratio of 1:1 are easily detected. Artificial damage locate at the depth of the 6th carbon mat was detected. Anisotropy of the thermal conductivity due to the carbon matt in carbon composite was observed and accounted for in the back projection inversion. The transform and the back projection calculations are very efficient and took four second each on laptop computer without the use of graphic processor unit.

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Application of Flash Pulse Thermography to Ceramic Matrix Composites at GE Aviation

Presenting author(s): Mr Christopher Uhl »

Co-Authors:

Room: Emerald III | 2:30 PM Wednesday, May 1, 2019

New Ceramic Matrix Composite (CMC) material systems in use at GE Aviation spurred the advancement of inspections methods to go along with the new materials. Flash pulse inspection was used extensively during the material development to better understand how material processing parameters affected the finished material. In the last few years these materials have moved from development to full scale production requiring the qualification of new inspection techniques to meet quality control requirements. Flash pulse thermography addresses many of the inspection challenges in CMCs however it was not in wide-spread use at GE Aviation prior to these applications. The method capability had to be quantified before it could be implemented for production quality assurance. This presentation will review the successful application of flash pulse thermography to complex shape CMC laminates. The primary examples are from Passport 20 Oxide-Oxide exhaust however the method has also been applied to parts manufactured with the SiC-SiC material systems and is applicable to other CMCs. Application examples will be presented along with some of the challenges and solutions that were deployed. The fundamentals of how the inspection works and the defect types that are evaluated will be introduced. An example of how a defect is detected and evaluated to determine the type will also be presented. Finally, some of the benefits and trade offs of this technique will be discussed.

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The Inspection and Characterization of Carbon Fiber Composites With Thermal Shearography

Presenting author(s): Mr John W Newman

Co-Authors:

Room: Emerald III | 3:00 PM Wednesday, May 1, 2019

Shearography is a full field NDT technique using an imaging interferometric capable of quantitative measurement of surface deformations as small as 2 nm.Using thermal stressing as the loading mechanism shearography has demonstrated exceptional sensitivity to internal anomalies and damage to carbon fiber laminates and honeycomb sandwich panels. This paper summarizes an investigation of shearography for damage in these structure types and compares results where applicable with UT C-Scan 1MHz TTU and the BondMaster in Pitch Catch with 5629 PHV Probe. The results demonstrate shearography can have a sensitivity equal or better than C-Scan for the components and materials evaluated. A novel dual channel duplex shearography system is also discussed providing full thickness resolution of anomalies in thick laminates.

First developed in the mid 1980’s, shearography has been highly developed by the authors’ team for nondestructive testing of aerospace, marine, automotive and architectural composites.

 This paper will also provide by way of background:

• Shearography NDT Theory

• Shearography NDT for delamination, disbonds cracks and wrinkled fibers,

• Applications: aerospace composites, launch vehicle and spacecraft

structures, marine composites

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Non-Destructive Evaluation and Inspection of Composite Materials using Thermal and Fast Neutron Imaging

Presenting author(s): Mr Michael J Taylor »

Co-Authors:

Room: Emerald III | 3:45 PM Wednesday, May 1, 2019

Phoenix LLC has developed, demonstrated, and deployed several neutron radiography systems for non-destructive testing using neutron radiography for commercial, aerospace, and military applications, among others. Neutron imaging a unique, powerful technique that identifies defects in materials where other NDT methods such as X-ray, ultrasound, Eddy-current testing, etc. will not suffice due to limiting densities, material composition and surface imperfections. A brief overview of neutron imaging, Phoenix’s current imaging systems, as well as the next generation system under construction, will be presented. Phoenix has recently performed several successful studies using neutron radiography for the inspection of composite materials, two such case studies will be presented examples. The first study investigates composite matrix ceramics with systematic uneven boron nitride coatings applied during fabrication were readily identified, which were completely transparent to all other NDT methods. The second case study investigates uptake of aqueous gadolinium solutions into ceramics was demonstrated as an application of NDT for the removal process of ceramic cores from high-temperature aircraft turbine blades. New applications will also be presented with an emphasis on the identification of otherwise undetected indications in such composite materials using the unique features of neutron imaging. These applications include: delamination of layers of depleted nuclear fuel plates, gas diffusion and void creation in high-temperature carbon fibers, dis-bonding of adhesives and crack formation in aircraft de-icing boots, and void creation in the curing process of resins and epoxies.

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Three-dimensional Radiographic Imaging of Complex Structures (TRICS)

Presenting author(s): Dr Eric Gans

Co-Authors: Mr Victor Grubsky, Mr Tom Nielsen, Mr Keith Shoemaker, Mr Volodymyr Romanov, Mr Frank Zahiri

Room: Emerald III | 4:15 PM Wednesday, May 1, 2019

Physical Optics Corporation (POC) has developed an automatic, three-dimensional (3D) Compton scattering imaging system for in-situ, nondestructive inspection (NDI) of large structures. Called Three-dimensional Radiographic Imaging of Complex Structures (TRICS), the system provides accurate detection and identification, and precise 3D localization/measurement of possible disbonds, core and skin defects including corrosion, and fluid intrusions. The system is based on a POC-developed high-contrast Compton imaging tomography technique, optimized for NDI of these structures, and POC-patented X-ray imaging optics. TRICS is a low-dose, in-field, noncontact system that allows for inspection while imaging from only one side. This allows for application to a variety of complex forms and structural locations that are often difficult to access and thus challenging to effectively inspect. The technology is currently at TRL-6/7 and has been used to evaluate a variety of material types including honeycomb sandwich structures and multilayer aluminum/composite structures with complex geometries found in aircraft, spacecraft as well as infrastructure such as oil/gas pipelines. Recent results have demonstrated the ability to not only identify and image (in 3D) structural defects but also measure and quantify materials loss due to corrosion (as low as 2%). In addition, the sensitivity of the system allows for differentiation of different type of liquid intrusions such as fresh or salt water, oil or other organic liquids. TRICS technology has garnered interest in a variety of commercial and military communities with current efforts supported by the US Air Force for maintenance depots application. Prior efforts have been supported by NASA and the Department of Energy among others.

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Novel Laser-Based Non-Contact Ultrasound Testing Method

Presenting author(s): Dr Balthasar Fischer »

Co-Authors: Mr Wolfgang Rohringer, Mr Ryan Sommerhuber, Mr Nils Panzer, Mr Igor V Ivakhnenko, Mr Clint Thomson

Room: Emerald III | 8:00 AM Thursday, May 2, 2019

The strong acoustic absorption in carbon fiber composites, foam and honeycomb structures can be a challenge for conventional ultrasound inspection. In order to improve coupling, a fluid such as water is typically used to enhance acoustic impedance matching. This necessity for water coupling may be impractical for inspecting large structures and rough surfaces and may not be allowed with open-core honeycomb material. We present a novel contact-free ultrasonic method for testing these scenarios: a short laser pulse is directed on the material’s surface, thereby exciting an ultrasonic shock wave without causing ablation. For signal detection, an optical ultrasound microphone is used that utilizes a detection laser internal to the microphone; notably, it is not directed on the sample surface. This makes the technology apt for testing rough surfaces, in contrast to conventional laser ultrasound, where a smooth surface condition is crucial to reduce laser scatter and to obtain a good signal. On the other hand, the frequency range of the presented detection approach is limited to approximately 2MHz, due to the strong absorption of high frequencies in air. However, recent testing on aircraft composite materials has shown the microphone to be effective in detecting programmed defects and porosity in the MHz and sub-MHz frequency band. When compared to air-coupled piezoelectric detection method, the optical microphone achieves higher sensitivity and superior spatial resolution of the material structure and defects. Scan results of carbon fiber and glass fiber honeycomb sandwich plates will be presented.

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Imaging of Structure in CFRP Composites with Laser-Ultrasonics: New Tools to Evaluate Heat Damage and Wrinkles

Presenting author(s): Dr Ivan Pelivanov

Co-Authors: Mr Lukasz Ambrozinski, Mr Matthew O'Donnell

Room: Emerald III | 8:30 AM Thursday, May 2, 2019

Carbon-fiber reinforced plastics (CFRP) are increasingly used for structures manufacturing. They must meet the highest safety requirements and must be inspected both in production and in the field. Visualization of large defects in composites have been demonstrated with many methods, but quantitative evaluation of the material structure performance is still a challenge. Although X-ray tomography can overcome this challenge, it is very time and money consuming and can only image small samples. Recent developments in non-contact fiber-optic detection [I. Pelivanov et al., J. Appl. Phys. 115 (2014)] have enabled high-resolution laser-ultrasound (LU) imaging of CFRPs in a fully non-contact manner [I. Pelivanov et al., Photoacoustics 4 (2016)]. Due to the broad bandwidth and high sensitivity of a recently developed fiber-optic Sagnac interferometer, LU images providing sub-ply resolution can probe the details of CFRP structures. Here we report our recent results on the evaluation of heat damage and detection of wrinkles in CFRP composites based on high-resolution LU images and signal processing techniques adopted from the medical ultrasound (US) field. To assess heat damage in composites we exploit the fact that a chemical degradation of the epoxy matrix alters the structural periodicity, which can be locally tracked with a mean characteristic frequency estimate. This method was originally applied in Doppler ultrasound widely used in biomedical field. To efficiently image wrinkles, we used a correlation based ‘tilt’, directional filtering technique derived from US strain imaging [L. Huang et al., IEEE Tran UFFC 56 (2009)].

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Acoustography NDE: A Simpler, Faster Ultrasonic Inspection of Composites

Presenting author(s): Dr Jaswinder S Sandhu

Co-Authors:

Room: Emerald III | 9:00 AM Thursday, May 2, 2019

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Projection Thermography of Large-Scale Composite Structures

Presenting author(s): Dr Steven M Shepard

Co-Authors:

Room: Emerald III | 9:45 AM Thursday, May 2, 2019

In recent years, thermography has gained wide acceptance as a primary method for NDT of polymer composite structures in both manufacturing and maintenance applications. In a typical inspection, an excitation source and IR camera are placed in close proximity to the target. The size of the inspection area is limited by the camera optics and pixel density relative to the minimum detectable flaw size requirement for a particular application (ASTM E2582-14 recommends that a minimum of 9 contiguous pixels cover the flaw), and the ability of the excitation to provide sufficient energy to the test piece. A typical inspection area for thermography is ~1 ft² for a camera with 640 x 512 pixels. Inspection of large structures is accomplished by moving the camera and excitation source over the part, either manually or assisted by a robot or gantry, in a grid pattern of 1 ft² cells, and then stitching the results together in software after appropriate signal processing has been performed. In an alternative configuration, Large-Scale Large-Area Thermography (LASLAT), optical energy is projected onto the part from a large standoff distance (~12 ft) and the camera optics are selected so that an inspection area ~20” x 15” can be inspected with spatial resolution and depth range that matches or exceeds the performance of a close proximity flash thermography system for detection of FOD, delamination and moisture ingress. Inspection of large structures is accomplished with the apparatus in a single position while the projected field of view is scanned over the entire part using only pan and tilt degrees of freedom.  

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Research Developments in Non-Invasive Measurement Systems for Aerospace Composite Structures at NASA

Presenting author(s): Mr Daniel Perey

Co-Authors:

Room: Emerald III | 10:15 AM Thursday, May 2, 2019

The use of composite materials continues to increase in the aerospace community due to the potential benefits of reduced weight, increased strength, and manufacturability. Ongoing work at NASA involves the use of the large-scale composite structures for spacecraft (payload shrouds, cryotanks, crew modules, etc). NASA is also working to enable both the use and sustainment of composites in commercial aircraft structures. One key to the successful deployment and sustainment of these large composite structures is the rapid, in situ characterization of a wide range of potential defects that may occur anytime during the vehicle’s life. Additionally, in many applications it is necessary to monitor changes in these materials over the life of the vehicle. Quantitative characterization through Nondestructive Evaluation (NDE) of defects such as reduced bond strength, microcracking, and delamination damage due to impact, are of particular interest. This paper will present an overview of NASA’s applications of advanced aerospace composites as well as the NDE technologies being developed for their characterization and sustainment. The approaches presented include investigation of conventional, guided wave, and phase sensitive ultrasonic methods, infrared thermography and x-ray CT techniques for NDE. Finally, use of simulation tools for optimizing and validating these techniques will also be discussed.

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Simulating Ultrasonic BScan Imaging of Tapered Composites Using Cloud Based FEA

Presenting author(s): Mr Jeff Dobson

Co-Authors:

Room: Emerald III | 10:45 AM Thursday, May 2, 2019

Carbon Fibre Reinforced Polymer (CFRP) composite components pose a challenge for ultrasonic Non-Destructive Testing (NDT) inspections due to their anisotropic material properties and often complex morphologies. Both aspects can detrimentally affect inspection performance due to ultrasonic waves being scattered, refracted and mode-converted as they pass through the component. Time domain Finite Element Analysis (FEA) can simulate this behaviour but has traditionally been too computationally expensive a solution for NDT, where many hundreds of simulations are required to reconstruct a full inspection. However, the advent of cloud computing allows 1000s of FEA simulations to be executed in parallel, enabling full BScans of CFRP components to be constructed in economical timeframes. We demonstrate the use of cloud based time domain FEA to generate full BScan images of tapered CFRP components. Component structures were created directly from ply layup specifications, simplifying the generation of complex 3D structures. All generated models include geometric details such as varying ply orientation, inter ply resin layers, ply drops and defects. 2D Simulations were executed in parallel, allowing a BScan inspection of over 100 individual measurements to be constructed in under 10 minutes. Further simulations were also performed in full 3D to include realistic 3D defects. Results show the difficulty of penetrating thick CFRP tapers, due to refraction and scattering in the composite. As expected, delaminations typically produce stronger indications than porosity. However, the angle of the delamination relative to the beam is shown to be critical, with delaminations not perpendicular to the axis proving difficult to detect.

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Latest enhancements in Non-Destructive Testing of composite materials

Presenting author(s): Mr Agata Surowiec

Co-Authors:

Room: Emerald III | 11:15 AM Thursday, May 2, 2019

Out-of-autoclave materials have long been an established material system for secondary structural applications; however, recent advancements in material properties allow for more advanced structural applications. Even though certain out-of-autoclave properties have achieved parity with autoclaved cured materials, out-of-autoclave materials are cured at reduced temperatures and pressures resulting in less compaction and homogeneity. The consequence is extraneous ultrasonic signals, due to internal reflections and refractions that cause attenuation, potentially masking defects leading to unidentifiable indications. Advanced algorithms were developed to improve the signal to noise ratio between constituents of similar acoustic impedance in bonded out-of-autoclave carbon fiber reinforced polymer assemblies. Conventional ultrasonic nondestructive testing techniques and analysis software cannot consistently achieve signal to noise ratios that meet quantifiable rejection thresholds of accurately sized peel ply inserts at the bonded interface of composite assemblies. Ultrasonic pulse echo with full waveform capture was used to inspect a reference standard with peel ply inserts placed between the adhesive and three-dimensional-woven fabric preform. The ultrasonic signal was produced by a 64 element array transducer with a central frequency of 2.8 MHz. Waveform post-acquisition analysis with post processing software was used to analyze and enhance the signal response between the peel ply and the bondline resulting in the final algorithm. To verify the results, the signal to noise ratio of each insert was calculated for both the raw and processed data. As the measure of detectability, the method relies on principles of statistical measurement to provide an industry standard signal to noise response of 3:1.

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Nondestructive Detection of Weak Bonds in Composite Structures Using Quantitative Percussion Diagnostics (QPD)

Presenting author(s): Mr James Earthman

Co-Authors: Mr Scott Poveromo

Room: Seattle Ballroom | 1:00 PM Thursday, May 2, 2019

Conventional nondestructive testing (NDT) techniques used to detect defects in composites are not able to determine intact bond integrity within a composite structure and are costly to use on large and complex shaped surfaces. To overcome current NDT limitations, a new technology was utilized based on quantitative percussion diagnostics (QPD) to better quantify bond quality in fiber reinforced composite materials. Experimental results indicate that this technology is capable of detecting 'kiss' bonds (very low adhesive shear strength) caused by the application of release agents on the bonding surfaces between flat composite laminates. Specifically, the local value of the probe force (force returned to the probe after impact) was observed to be lower for the release coated panels. Experimental results were compared to results from finite element analysis (FEA) models to better understand the effect of bond strength on the visco-elastic behavior of the laminates during percussion testing. This comparison shows how a lower quality bond leads to a reduction in the percussion force by biasing strains to the percussion tested side of the structure. FEA results were also used to estimate the spatial resolution and reduction in bond stiffness that would be detectable using QPD. The present model predicted that weak bond areas larger than 13 mm x 13 mm should be resolvable when the bond stiffness is reduced to 5% of its nominal value.

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Advances in Linear Array Ultrasonic Testing of Composites

Presenting author(s): Mr John D Register

Co-Authors:

Room: Emerald III | 1:30 PM Thursday, May 2, 2019

Manual Ultrasonic testing (UT) continues to Bridge the gap between portable Ultrasonic Equipment and large Automated equipment. Ultrasonic equipment also needs to be designed for the inspection of Composite materials and not borrow Ultrasonic technologies that were developed for Steel angle beam testing. New Linear Array equipment along with array scanners are now available that were developed for Ultrasonic Composite Inspection. By using linear Array Ultrasonic equipment this solves three main issues with UT of Composites; first we need to only have linear array available on portable UT equipment, this helps remove the complexity of using a traditional Phased Array Ultrasonic Flaw detector for composite detection. Second by using only linear array ultrasonic testing mode, this may take away the need of an additional 80 hours of PAUT required training. Third; Software that is developed for one use in the case of linear Array testing of Composite allows the manufacturer to focus on the tools that are needed for the technician to evaluate and asses scans for acceptance. This paper will address Linear Array testing of Composites, defects that occur in composites and their relationship for linear array testing. We will also review equipment for linear array testing and Software that can be used specifically for Ultrasonic testing of Composites. This paper is intended for NDT Technicians, Engineers and Quality Management that want to lean more about NDT of Composites and New emerging technologies in this field.

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Detection of Unacceptable Features in Manufactured Composites Parts Using Ultrasonic Coda Wave Comparison Technique

Presenting author(s): Dr Thomas Schumacher

Co-Authors: Mr Ali Hafiz, Dr Qiang Wang

Room: Emerald III | 2:00 PM Thursday, May 2, 2019

Many industrially manufactured parts for cars, airplanes, and pressure vessels are made of composite materials such as glass fiber reinforced polymers (GFRP). During manufacturing, quality control (QC) is used to detect the parts that contain damage or deviate from the target geometry. This research explores the ultrasonic coda wave comparison technique as a means to detect unacceptable parts. In the proposed approach, an ultrasonic signal collected from a manufactured part is compared to a signal that was collected from an acceptable reference part. A pitch-catch setup was used in this research consisting of one transmitting and one receiving ultrasonic transducer. The two ultrasonic signals, including the coda portion, are compared using a similarity parameter. The coda portion has been found extremely sensitive to small damage with a size that is well below the wavelength of the used ultrasonic pulse. This presentation provides an overview of the proposed approach and discusses some preliminary laboratory work on a small GFRP plate to demonstrate its potential.

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Predicting Bond Performance of Composites Through Non-Destructive Testing

Presenting author(s): Ms Brooke Campbell

Co-Authors:

Room: Emerald III | 2:30 PM Thursday, May 2, 2019

In aerospace manufacturing, the successful creation of adhesively bonded primary composite structures hinges on being able to control bond surfaces and predict bond reliability. Surface preparation is a critical aspect prior to bonding, requiring a non-destructive evaluation to verify and characterize acceptable composite surfaces. Traditional methods for evaluating composite surfaces, such as dyne inks and water break tests, can be subjective and destructive or otherwise inappropriate for a manufacturing environment. An alternative non-destructive method for determining surface energy is achieved via water contact angle measurements. X-Ray Photoelectron Spectroscopy (XPS) is a surface sensitive technique for characterizing the top 10 angstroms of a surface. Water contact angle measurements also probes this uppermost layer. Quantitative results, as determined by XPS, directly correlate with contact angle measurements and therefore also with surface energy. XPS verifies the use of water contact angle measurements to predict bond performance. This presentation will discuss the use of water contact angle measurements to reliably and objectively characterize composite surfaces with regard to surface preparation and predict adhesion in bond performance.

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NDE for Composite Manufacturing: A view of the present and future opportunities

Presenting author(s): Dr Gary E Georgeson

Co-Authors:

Room: Emerald III | 3:15 PM Thursday, May 2, 2019

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