Periodic Reporting for period 2 - AUTHENTIC (AUTOMATED THERMOGRAPHIC INSPECTION SYSTEM FOR THE INSPECTION OF AERONAUTIC WELDINGS)
Berichtszeitraum: 2022-03-01 bis 2022-12-31
The rotating hub is a safety critical module, which sometimes has internal flow passages making the geometry complex. This complexity leads to several subcomponents integrated into a weld assembly. Welding is a critical process which needs to be mastered with subsequent Non Destructive Testing (NDT). Nowadays, inspections are carried out using Radiography for volumetric defects and Fluorescent Penetrant Inspection (FPI) for surface defects, which show several drawbacks.
Thermography opens a new paradigm by allowing automation of both the inspection and the detection, eliminating possible human execution errors and mistakes in the defect detection. AUTHENTIC, as part of the Clean Sky 2 programme, addresses the development and adoption of automated active thermography to detect surface defects. Thus, the substitution of FPI is sought through Thermographic NDT. This technology consists of heating a surface (in this case welds) with air, laser, lamps, induction, etc. and examining the heat propagation with a thermal camera. Defects act like barriers to heat propagation and this concentrated heating in the defective areas is directly captured by the camera, allowing the location of defects with just the processing of the recordings.
The impact for society could be summarized in the following environmental impacts:
- Reduce CO2 emissions (objective: 10%) since the new system will guarantee a higher POD that will allow optimized engine designs aerodynamically more efficient.
- Avoid the use of polluting substances during NDT testing such as penetrant developers and solvents providing a completely clean inspection, safe in all aspects.
- Healthier working conditions for NDT technicians: (i) they will not have to be in a dark enclosure during the inspection, as in FPI. (ii) They will not have to employ or inhale current dangerous FPI products.
As a result of the project a fully automated inspection system based on inductive active thermography has been developed for the detection of superficial defects present at welded safety-critical engine components. The automation is present twice:
- the inspection process itself through an adequate robotic system and
- the defect detection, characterization and localization thanks to developed algorithms.
In summary, the developed system provides: (i) faster inspections on full-scale components, (ii) elimination of human subjectivity from inspections, and (iii) a healthier and cleaner working environment for technicians. It can be used in both the final inspection and quality acceptance stage. Finally, the probability of detection of the new system is superior to traditional inspection techniques like FPI and it can incorporate, if needed, the support of a second sensory (based on acoustic emission or vision system) for complex cases to enhance its robustness.
Thermography opens a new paradigm by allowing automation of both the inspection and the detection, eliminating possible human execution errors and mistakes in the defect detection. AUTHENTIC, as part of the Clean Sky 2 programme, addresses the development and adoption of automated active thermography to detect surface defects. Thus, the substitution of FPI is sought through Thermographic NDT. This technology consists of heating a surface (in this case welds) with air, laser, lamps, induction, etc. and examining the heat propagation with a thermal camera. Defects act like barriers to heat propagation and this concentrated heating in the defective areas is directly captured by the camera, allowing the location of defects with just the processing of the recordings.
The impact for society could be summarized in the following environmental impacts:
- Reduce CO2 emissions (objective: 10%) since the new system will guarantee a higher POD that will allow optimized engine designs aerodynamically more efficient.
- Avoid the use of polluting substances during NDT testing such as penetrant developers and solvents providing a completely clean inspection, safe in all aspects.
- Healthier working conditions for NDT technicians: (i) they will not have to be in a dark enclosure during the inspection, as in FPI. (ii) They will not have to employ or inhale current dangerous FPI products.
As a result of the project a fully automated inspection system based on inductive active thermography has been developed for the detection of superficial defects present at welded safety-critical engine components. The automation is present twice:
- the inspection process itself through an adequate robotic system and
- the defect detection, characterization and localization thanks to developed algorithms.
In summary, the developed system provides: (i) faster inspections on full-scale components, (ii) elimination of human subjectivity from inspections, and (iii) a healthier and cleaner working environment for technicians. It can be used in both the final inspection and quality acceptance stage. Finally, the probability of detection of the new system is superior to traditional inspection techniques like FPI and it can incorporate, if needed, the support of a second sensory (based on acoustic emission or vision system) for complex cases to enhance its robustness.
AUTHENTIC project is composed of two main blocks.
- POD analysis considering the manufactured samples to demonstrate quantitatively that Thermography for inspection is better than traditional FPI.
- Development of the inspection system and the final demonstration.
To carry out POD calculations all samples were measured through Thermography, Standard Fluorescent Penetrant Inspections, Microscopic Images, Extended FPI and Computer Tomography.
The thermographic measurements have been evaluated directly by an inspector using a processed image, and using detection algorithms. During measurements, these relevant aspects were considered:
- Manufacturing of the samples with defects with a Varestrain Test Machine
- Representative crack size and distribution
- A realistic crack length/depth ratio
The results of the a90/95 values were the following:
- Cast inconel 718, TIG welds: 0.862
- PBF inconel 718, Laser welds: 1.382
- Cast Haynes 282, TIG welds: 1.288
Final Demonstration of the developed Inspection System was carried out at LORTEK with an aeronautical component part provided by GKN. For that, it was necessary to consider an adequate fixing of the component, and design and manufacture the necessary robot heads (with the corresponding inductor).
Two robot heads and an adequate fixing for the component for thermography were designed and manufactured. The first head can perform inspections on welds with easy accessibility, while the second robot head with special infrared mirrors is aimed at the ‘inner’ welds, located in between the vanes. Both robot heads use the same inductor, which allows crack detection in any orientation, and has led to a patent application.
The CAD designs of both robot heads and fixtures are fed into a CAD-CAM software to virtualize the inspection cell and calculate inspection trajectories. The virtual environment allows:
- Compute total inspection times
- Check that neither the robot head nor the inductor crash in the inspection cell
A text file is also generated to specify the thermographic parameters needed for each point. They are introduced in the Inspection Interface developed and the inspection can be executed. All the information can be seen in a web interface developed by Lortek that allows the inspector to revise all inspection results, and if the system has ignored a defect (false negative), the inspector can update and correct it. These changes are automatically stored in the system. In this way, they can be introduced into the re-training of the automatic defect detection models later.
Four exploitable results were generated related to the new induction thermograpy based NDT system, leading to a patent. Several dissemination actions were carried out, including project webpage, partners' webpages, many posts in LinkedIn and Twitter, a journalistic article, 4 conferences and 3 scientific publications.
- POD analysis considering the manufactured samples to demonstrate quantitatively that Thermography for inspection is better than traditional FPI.
- Development of the inspection system and the final demonstration.
To carry out POD calculations all samples were measured through Thermography, Standard Fluorescent Penetrant Inspections, Microscopic Images, Extended FPI and Computer Tomography.
The thermographic measurements have been evaluated directly by an inspector using a processed image, and using detection algorithms. During measurements, these relevant aspects were considered:
- Manufacturing of the samples with defects with a Varestrain Test Machine
- Representative crack size and distribution
- A realistic crack length/depth ratio
The results of the a90/95 values were the following:
- Cast inconel 718, TIG welds: 0.862
- PBF inconel 718, Laser welds: 1.382
- Cast Haynes 282, TIG welds: 1.288
Final Demonstration of the developed Inspection System was carried out at LORTEK with an aeronautical component part provided by GKN. For that, it was necessary to consider an adequate fixing of the component, and design and manufacture the necessary robot heads (with the corresponding inductor).
Two robot heads and an adequate fixing for the component for thermography were designed and manufactured. The first head can perform inspections on welds with easy accessibility, while the second robot head with special infrared mirrors is aimed at the ‘inner’ welds, located in between the vanes. Both robot heads use the same inductor, which allows crack detection in any orientation, and has led to a patent application.
The CAD designs of both robot heads and fixtures are fed into a CAD-CAM software to virtualize the inspection cell and calculate inspection trajectories. The virtual environment allows:
- Compute total inspection times
- Check that neither the robot head nor the inductor crash in the inspection cell
A text file is also generated to specify the thermographic parameters needed for each point. They are introduced in the Inspection Interface developed and the inspection can be executed. All the information can be seen in a web interface developed by Lortek that allows the inspector to revise all inspection results, and if the system has ignored a defect (false negative), the inspector can update and correct it. These changes are automatically stored in the system. In this way, they can be introduced into the re-training of the automatic defect detection models later.
Four exploitable results were generated related to the new induction thermograpy based NDT system, leading to a patent. Several dissemination actions were carried out, including project webpage, partners' webpages, many posts in LinkedIn and Twitter, a journalistic article, 4 conferences and 3 scientific publications.
Nowadays, inspection of welds on engine components is carried out manually by an operator using FPI. Inspections are slow and the technology is dirty and unhealthy for the technicians.
- This manual technology can be substituted by automated Inductive Active Thermography using appropriate robot and subsystems. Faster, healthier and totally clean inspections are achieved.
Inductive Thermography is nowadays employed at laboratory level and in a few industries for the inspection of some geometrically simple components that do not involve complex inspection trajectories.
- Inductive thermography was adapted to inspect geometrically complex structures like welded engine components.
Inductive thermography FEM simulations are nowadays qualitative and the existing models are simple.
- FEM simulations have been carried out considering the physical properties of the developed inductors.
The detection of the defects is performed manually by the operator, who performs the inspection according to a standard.
- Defect Detection has been automatized avoiding human error mistakes.The inspection results in a report consisting of a list with the location and characteristics of all the detected defects.
Due to the subjectivity of the inspection, POD curves are computed for each operator. They can be computed using one of the existing standards.
- A unique POD curve was obtained for certain material – weld type pair and conditions.
AUTHENTIC will provide CO2 emissions reduction related to the manufacturing process (reducing production time, post-processing and waste generation) and use of aircraft (reducing dissassembly and repairing, and increasing lifetime). It will also foster the implementation of open rotor engine designs.
- This manual technology can be substituted by automated Inductive Active Thermography using appropriate robot and subsystems. Faster, healthier and totally clean inspections are achieved.
Inductive Thermography is nowadays employed at laboratory level and in a few industries for the inspection of some geometrically simple components that do not involve complex inspection trajectories.
- Inductive thermography was adapted to inspect geometrically complex structures like welded engine components.
Inductive thermography FEM simulations are nowadays qualitative and the existing models are simple.
- FEM simulations have been carried out considering the physical properties of the developed inductors.
The detection of the defects is performed manually by the operator, who performs the inspection according to a standard.
- Defect Detection has been automatized avoiding human error mistakes.The inspection results in a report consisting of a list with the location and characteristics of all the detected defects.
Due to the subjectivity of the inspection, POD curves are computed for each operator. They can be computed using one of the existing standards.
- A unique POD curve was obtained for certain material – weld type pair and conditions.
AUTHENTIC will provide CO2 emissions reduction related to the manufacturing process (reducing production time, post-processing and waste generation) and use of aircraft (reducing dissassembly and repairing, and increasing lifetime). It will also foster the implementation of open rotor engine designs.