TTU Phased Array: Quality and Productivity

Transcription

1 6th International Symposium on NDT in Aerospace, 12-14th November 2014, Madrid, Spain - TTU Phased Array: Quality and Productivity More Info at Open Access Database Miguel Ángel NIETO, Zaida RE, Esmeralda CUEVAS 1 Aeronautical NDT Techniques, Direction of Technology and Product Development, TECNATOM, San Sebastián de los Reyes, Madrid, Spain Phone: , Fax: ; manieto@tecnatom.es Abstract The wide experience of Tecnatom in the field of inspections by conventional Through-Transmission and Pulse Eco Phased Array, together with the capabilities of the Tecnatom products of ultimate generation, INSPECTVIEW (Software) and FPA 128 M (Phased Array Electronics), and an innovative mechanical development for the Nozzles, it gives as result an UT technique Through Transmission Phased Array (TTU PA) whose aims is to cover the high range of quality and productivity required by the aeronautical industries. The mix of an innovative nozzle s design, a thorough study of Fluid Mechanics and a wide selection of parts with different geometries to carry the water, resulting in a laminar stream that allows an excellent quality transmission of the ultrasonic wave. To apply new technologies in the design and manufacture of parts, especially using Additive manufacturing (AM), has allowed, from the original design, being modified and tested to optimize each piece nozzle system and achieve the desired quality. The optimization of the water system is the key element for the precise application of this technique. A complex system of tubing assures to keep caudal and pressurized water stream constants in any inspection position. New- generation Hardware and Software developed totally by Tecnatom allow the growth of this TTUPA technique. This new HW-SW together, allow the use of the most advanced probes and the handling and generation of specific focal laws for this type of inspections. The Phased Array probes have been designed considering the necessary characteristics for the inspection of sandwich materials who attenuate the ultrasonic signal greatly. The emission and reception probe s characteristics have been reinforced through the configuration of different focal laws for each scene. The modification of focal laws extend the range of materials configurations for inspection, focusing individually on the request of each part, minimum size of defect, step, etc. The TTU Phased Array Techniques have been subjected to various strict tests in order to ensure the requirements of the biggest worldwide aeronautical manufactures. Parts with sandwich and honeycomb configurations have been tested with quality results equal or even better that TTU conventional technique but with a rise in productivity seven times more than the conventional technique. Keywords: Through Transmission Phased Array (TTU PA), aeronautical, honeycomb, sandwich, carbon fiber composite 1 Introduction This paper describes the evolution of the development of the Through-Transmission Phased Array technique for aeronautical components. TECNATOM is a company with more than 50 years of experience in NDT. Fifteen years ago, TECNATOM decided to widen its strategy and to extend its activities from the nuclear sector to other markets, with priority given to the field of aeronautics. Throughout these fifteen years in which Tecnatom has developed different equipment and systems for aeronautical applications, there has been a natural evolution, both of the mechanical systems, whose scope and accuracy of movement have improved, and for the non-destructive tests.

2 2 Evolution of NDT Techniques The natural evolution of non-destructive testing started fundamentally with the use of ultrasounds generated by a single piezoelectric element until the use of the array of elements. 2.1 Through Transmission: This is generally used for materials with high attenuation, since the sound passes through the material once only. The disadvantage is that access is required to both sides of the component to be inspected and that no information on the position in depth of the defect is provided. 2.2 Pulse-echo: Figure 1. Through Transmission configuration. Access is required from one side only of the component and information is provided on the exact position of the indication, including depth. This is not suitable for high attenuation materials since the sound passes through the material twice. Figure 2. Pulse-echo configuration. 2.3 Pulse-echo Phased Array: From the use of mainly conventional piezoelectric ultrasonic with single elements there has been an increase in the number of elements involved, leading finally to the possibility of configuring them electronically, optimizing the focusing and orientation of the ultrasonic beam.

3 2.4 Through Transmission Phased Array: The joining of Phased Array technique and Transmission provides results with the quality and productivity offered by the Phased Array applied to highly attenuating materials that need to be inspected with Through Transmission technique. 3 Through Transmission Phased Array 3.1 The Mechanical System. The nozzle design along with the water system are two of the bases of this development. Nozzles are designed capable of generating a laminar jet of water of 20 mm diameter. An internal grid system eliminates turbulence generated by a water system having a flow rate of 4 thousand liters per hour. The system consists of a set of grids with different pore sizes. The purpose of these grids is to guide the flow of water through the pores of the grid thus reaching the laminar regime. Of course, no water is wasted, this is continuously recirculated through the system, through filters that remove particles emerging from fiber parts inspected, maintaining pressure and avoiding bubbles. Figure 3.TTU PA Squirter Applying the new manufacturing techniques (Additive manufacturing) has been possible to test a large number of geometries to optimize the output of the water jet.

4 Figure 6. Nozzle output Test 1 Figure 7. Nozzle output Test 2 Figure 8. Nozzles output Test 3 Figure 9. Nozzle output Test 4 Figure 10. Nozzle Output Test 5 The best option has been decided taking into account the distance between nozzles, signal homogeneity and their response to variations in geometry to inspect. Finally, the full system has been integrated with the RABIT technology where robot movements are associated with Ultrasonic data.

5 Figure 11. Rabit The Rabit technology adapts the characteristics of industrial robots and incorporates them in an overall inspection system bringing together all the hardware and software capabilities required to plan and to configure ultrasonic inspections (specification of probes, definition of the part to be inspected obtaining also geometries by 2D Laser, definition and generation of focal laws, definition of inspection parameters, ultrasonic calibration). 3.2 UT System. Hardware and Software. New-generation Hardware and Software developed totally by Tecnatom allows the growth of this TTU PA technique. The capabilities of electronic Phased Array SONIA 128 FPA along with the new software developed by Tecnatom (InspectView) allow generating Phased Array configurations to work optimally in Through Transmission technique. 3.3 Transducer. The transducer has been designed to combine the quality of small elements of the Phased Array Transducers with the power of the Through Transmission Transducers, to generate an array of ultrasonics waves that can go through high attenuation materials.

6 3.4 Focal Laws. In the generation of focal laws for TTU is where the big leap in quality that the Phased Array add to the conventional technique is appreciated. The current simulation programs (CIVA) allow previous studies to ensure that the final configuration of the focal laws are adapted to the needs of component inspection. Figure 12. Civa Simulations I The versatility of Phased Array allows that the same probe can be used for inspecting components with different characteristics, increasing the number of elements for each focal law in highly attenuating materials inspection or decreasing the number of elements and the step between focal laws are used for inspecting areas with more restrictive detection criteria. Figure 13. Civa Simulations II Furthermore, our software allows the possibility of multiple shots in each position, several different configurations of focal laws that acquire information from the same part with

7 the ability to represent that information in different C-Scan, one for configuration or merge all the information in a single C-scan based on the criteria required (Maximum or minimum amplitude). Of course, the features and functionalities of typical phased array systems are maintained in their application to the Through Transmission Phased Array Technique, eg. focalization, which gives the ability to focus on areas of interest, bonding areas, intersections between the laminate and the foam or between the laminate and honeycomb. Also the possibility of different settings for Emission and Reception will optimize the characteristics required for each inspection. 3.5 Validation Test. The TTU Phased Array Techniques have been subjected to various strict tests in order to ensure the requirements of the biggest worldwide aeronautical manufacturers. System has been configured in order to optimize seven central focal laws with a 2mm step, allowing the inspection of 14 mm component in each sweep. This optimization has been performed at a nozzle spacing of 100 mm and subsequently also has been tested at 120 mm and 150 mm spacing between nozzles. The velocity of inspection for conducting the tests has been 750 mm / s. With this configuration, an inspection, with Rabit technology, scans the whole working area, obtaining a homogeneous signal with 98% of samples within a range of 6 db. Parts of laminated material up to 10 mm thickness have been inspected. Indications of 6 x 6 mm are detected with good results in both, the location and sizing of flaws. Also parts with sandwich configuration (laminate / foam / laminate) and honeycomb have been tested with similar results. Additionally, the system has been qualified according to the parameters of the Airbus normative AITM (Evaluation of conventional ultrasonic inspection facilities, equipment and probes) and AITM (Evaluation of phased-array ultrasonic inspection facilities, equipment and probes)

8 Figure 14. Laminate Inspection 1 Y Figure 15. Laminate Inspection 2 Figure 16. Sandwich Inspection 1 Y Y Figure 17. Sandwich Inspection 2

9 4 Conclusions. The development of this system has always had the goal of industrialization and the imminent possibility of putting the system into production. To achieve this all relevant parameters have been studied from a point of view of feasibility and industrialization. That is why a water jet of 20 mm diameter was considered. A larger diameter is achievable but the water system should have dimensions that exceed the characteristics of conventional systems of an industrial plant. From the available 20 mm diameter, the central 14 mm have been optimized because this is 7 central focal laws which maintain the quality of the signal, the required homogeneity, on virtually any inspection conditions. Once all the quality parameters have been fixed, it is concluded that Tecnatom proposal for Through Transmission Phased Array increases the production rate in seven times compared with Conventional TTU (2 mm scan). Through Transmission Phased Array Techniques improves the performance of conventional technique and satisfies other need of today's aviation industry: Productivity References [1] AITM (Evaluation of conventional ultrasonic inspection facilities, equipment and probes) [2] AITM (Evaluation of phased-array ultrasonic inspection facilities, equipment and probes)