Pavel Doronkin

Current helicopter onboard monitoring systems are not effective enough, and most helicopters do not even have them. As helicopter unit state is not clearly known, it is subject of preventive maintenance. To maintain helicopters predictively reducing repair costs and time, the techniques are required that allow diagnosing the operating units in field conditions for all helicopters. This work is aimed to practically check the Vibropassport techniques allowing the predictive maintenance on the operating helicopter. The Vibropassport using high-order models considers the spatial vibrations in a wide frequency range, applies diagnostic parameters at the normalized scale, and allows diagnostics using a single field inspection. The main finding of the work is that the Vibropassport-based system adapted to a specific helicopter type allows the detailed diagnostics of the engines, gearboxes and transmissions based on the data of a single test in field conditions. Applicability of the Vibropassport system in field conditions was demonstrated on an operating helicopter, and the vibration-based diagnostics estimates whether the unit state complies with the thresholds common for a wide range of similar units. The Vibropassport-based system makes the predictive maintenance possible, reducing costs of maintenance and repair for helicopters, including those without onboard monitoring systems.

The development of non-destructive testing methods for aircrafts, in particular vibration diagnostics, nowadays makes it possible to make a transition to predictive maintenance. To ensure such maintenance, the hidden faults of structures at an early stage of development to be diagnosed. Vibration diagnostic techniques are already used for helicopters and considered as promising but most helicopters do not have on-board systems. An approach that does not require specialized onboard equipment is needed. To be effective such an approach should provide diagnostics in field conditions using a one-time inspection. Application of the system’s prototype, which meet these requirements is suggested and discussed in this paper. Workability of the methods used has been demonstrated in testing of healthy and aged sets of main rotor blades. The method of blades state assessing using modal diagnostic parameters are briefly described and comparison of diagnostic parameters between healthy and aged blades are discussed.

One of the most sensitive parts of a wind turbine to environmental influences are the rotating blades. Today, there are many technologies available to assess blade condition, but they all need to be developed to become more cost-effective and more sensitive to fault detection. The algorithms and methods of the modal passport discussed in this paper propose a non-destructive technique already used for helicopter blade condition monitoring and diagnostics. This technique requires adaptation to wind turbine blades because they have larger dimensions, other materials and design, and operate under other conditions. To provide this adaptation, computational and experimental data on the modal properties of the blades must be obtained. The first stage of the study is planned to be performed on a scale model on stationary and rotating test rigs. At this stage of the study, algorithms and methods for the formation of a roadmap to develop a modal passport for a series of composite models of a wind turbine blade are considered. The initial stage of modal passport development included FE modeling of the blade model, calculation of modal parameters, fabricating the blades, and preparing the test equipment. Quantitative assessment of modal tests volume made it possible to plan the step-by-step execution of the roadmap for development and experimental application of the modal passport of wind turbine blade models.

One of the most sensitive parts of a wind turbine to environmental influences are the rotating blades. Today there are many technologies available to assess its condition, but they all need to be developed to become more cost-effective and more sensitive to fault detection. The Modal Passport algorithms and methods discussed in this paper proposes the technique already used for helicopter blade condition monitoring and diagnostics. This technique requires adaptation to wind turbine blades because they have larger dimensions, material and design, and operate under other conditions. To provide this adaptation, computational and experimental data on the modal properties of the blades must be obtained. The study is planned to be performed for a scale model on stationary and rotating test rigs. The algorithms and methods of the Modal passport considered in this study stage were used to form a roadmap for developing the passport for a series of composite models of a wind turbine blade. The stages of the Modal passport development include FE modeling of the blade model and calculation of modal parameters. Estimated volume of modal tests made it possible to plan the step-by-step execution of the roadmap works for development and experimental application of the modal passport of wind turbine blade models.

Health monitoring of critical structures, that form parts of serial operating objects, is a pressing task. The Operational Modal Analysis (OMA) techniques could be the optimal solution. An inexpensive measurement system, such as the OMA, uses a lot of sensors for structural response assessment. The health monitoring of serial structures has to also consider possible deviations between samples. A solution providing the OMA application includes the compact measurement system based on piezoelectric film sensors and modal passport (MP) techniques. For validation of the proposed approach, a series of five similar composite cylinders, with a network of piezoelectric film sensors, was used. Applying modal tests on the specimens, and using OMA with MP methods, the set of typical modal parameters was determined and analyzed. The results of the study confirmed the feasibility of the sensor network and its applicability for structural health monitoring of serial samples using OMA methods. The proven effectiveness of OMA/MP techniques, combined with a sensor network, provides a prototype of intelligent sensor technology, which can be used for health monitoring of structures, including those that are part of an operating facility.