Chapter 19 Distributed Acquisition and Processing Network for Experimental Vibration Testing of Aero-Engine Structures Michal J. Szydlowski, Christoph W. Schwingshackl, and Andrew Rix Abstract Detailed vibration testing of large assembled structures, such as aeroengines, leads to significant requirements on data acquisition and processing. This can lead to high system cost and long post processing times, which often limit the amount of data that can be acquired. A novel hardware-software acquisition system combination is proposed here to overcome some of the challenges of large scale data acquisition, based on the idea to distribute the acquisition and data processing load between a network of specialized acquisition nodes. The nodes work in parallel and are independent of each other, while sharing a synchronization clock. Each node has the capability to process the data being acquired on-line. The network allows for testing of novel data analysis methods and its modular nature enables an easy expansion of the system when required. Keywords Vibration testing · Experimental · Data acquisition systems 19.1 Introduction Many factors influence the dynamic responses of complex rotating machinery. Gas turbine engines are good examples of such a complex system [1]. Experimental testing is a necessary tool in order to increase the understanding of the dynamic behaviour of such structures [2]. Engine vibration testing is a difficult task, the success of the testing procedure is dependent on many elements of the process [3–6]. From a technical stand point, it requires capturing large numbers of data points from multiple sensors at different sampling frequencies, that may come for a variety of sensors [7–10], such as accelerometers, blade tip timing systems, strain gauges, torque meters. Forced response analysis of a complex assembled structure may also require specialised multichannel signal generators for different types of exciters across the system. Normally very expensive high channel I/O testing systems will be used for this type of testing, which will be designed and optimised for a specific test setup, making them difficult to scale, and limiting their use for a research environment. Peeters et al. [4] shows in his paper modern approaches to on ground airplane vibration testing, where the acquisition system has seven hundredth channels. The setup is very complicated and requires several processing stations to go through the data. The complexity of engine testing programs is also shown by Howe and Carmichael [7]. To overcome some of the challenges for large scale data acquisition, the authors present a hardware-software signal acquisition architecture based on a network of specialized data capture and processing devices. The system is designed to meet the requirements of large scale vibration testing in a research environment, with a special focus of reasonable cost, flexibility and scalability. 19.2 System Concept Rather than using a single, powerful and expensive system that does it all, the system is designed so the data capture and processing loads are distributed between several nodes of a network, where each node consists of a lower cost data acquisition M. J. Szydlowski ( ) · C. W. Schwingshackl Imperial College London, South Kensington, London, UK e-mail: m.szydlowski@imperial.ac.uk A. Rix Rolls-Royce plc, 62 Buckingham Gate, London, UK © The Society for Experimental Mechanics, Inc. 2021 C. Walber et al. (eds.), Sensors and Instrumentation, Aircraft/Aerospace, Energy Harvesting & Dynamic Environments Testing, Volume 7, Conference Proceedings of the Society for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-47713-4_19 209
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