Z-Coupled Full System for Attenuation of Vibrations

Final Report Summary - Z DAMPER (Z-Coupled Full System for Attenuation of Vibrations)

Executive Summary:
The aim of this project is to find and demonstrate an optimal system for minimizing the transmission of vibrations generated in the Counter Rotating Open Rotor to the fuselage. The Sustainable and Green Engine (SAGE) ITD, DREAM projects and Clean Sky are FP7 R&D projects devoted to develop the innovative engines for the future aircrafts. Under an event of a blade loss, expected vibrations coming from the damaged CROR engine are particularly high and compromise the manoeuvrability of the aircraft. In addition, the environmental conditions on the surroundings of the engine area are highly demanding. Close to the excitation source, temperatures from 250 to 650ºC are expected.
All kinds of conventional –passive, dynamic, active and semiactive- solutions for reduction of vibrations were considered for optimization. The hard constraints of space, temperature and low frequency had spoil most of the well-known conventional approaches. However, in order to overcome these difficulties and to increase the efficiency of these “well-known” solutions the use of a new technology of Impedance coupling has been assessed during this project.
The Z-Damper technology, patented by MAGSOAR SL, provides a non-contact, reliable mechanism able to multiply the efficacy of any conventional element (passive dampers, tuned vibration absorbers, active actuators or semiactive devices) reducing the overall required mass and volume of the devices. Two main prototypes have been manufactured and tested:
• Z-Transmitter prototype of an impedance coupling device that can be coupled to external elements such as springs or inertial mass. Operation as an impedance coupling device and as a tuned vibration absorber has been demonstrated.
• Z-Damper prototype, a passive solution consisting of a integrated high-temperature pure dissipative damper able to work at temperatures up to 250ºC.
Both prototypes have been tested under realistic operational conditions demonstrating the expected behaviour. In addition, a dummy of the Z-Damper has been designed and manufactured in order to evaluate various linear bearing technologies when operating under the expected Z-Damper conditions.

Project Context and Objectives:
The aim of this project is to find and demonstrate an optimal system for minimizing the transmission of vibrations generated in the Counter Rotating Open Rotor to the fuselage. For this purpose all kinds of conventional –passive, dynamic, active and semiactive- solutions for reduction of vibrations will be considered for optimization. The hard constraints of space, temperature and low frecuency could spoil most of the well-known conventional approaches. However, in order to overcome these difficulties and to increase the efficiency of these “well-known” solutions the use of a new technology of Impedance coupling will be also explored. This exclusive and new technology has become available as a result of the FP7-Space MAGDRIVE project and provides a non-contact, reliable mechanism able to multiply the efficacy of any conventional element (passive dampers, tuned vibration absorbers, active actuators or semiactive devices) reducing the overall required mass and volume of the devices. It can also integrate any of the above cited other conventional elements in a compact built-in design. Thanks to the non-contact characteristic and using appropriate common materials, the Z-Damper is expected to work at a temperature up to 700ºC providing a protective “heat barrier” for the conventional element in addition to the “multiplier effect” on the efficacy.
MAG SOAR is a Small Technology-based Company incorporated as a spin-off of the above mentioned FP7-Space project MAGDRIVE. Its engineers have a recognised long expertise in Noise&vibrations projects –using all the existing known technologies, modelling, testing and instrumentation-. Additionally, MAG SOAR currently counts with aeronautical customers –i.e. Airbus Military- and is familiar with their procedures and standards. This, together with the simplicity of the consortium and the proved expertise in coordinating FP7 projects –including Clean Sky- makes MAG SOAR the perfect choice for this topic.
As part of the project objectives, two prototypes has been manufactured and tested up to TRL 5 in a relevant environment. A dedicated testbench has been manufactured and set up to reproduce the environment close to the CROR engine.

Project Results:
Transmission of vibrations through a structure and systems to reduce, mitigate or supress them are one of the most studied topics in Mechanical Engineering. The simplest way to reduce vibrations transmissivity of, for example, a rotating machine to the ground is to increase the elasticity of the ground-connections.
Mechanical impedance is a key concept for studying vibrations in mechanical systems as well. The concept is equivalent to that of impedance in an electric circuit (the opposition a circuit presents to the flow of a current given an input voltage) which is of great importance in the design of AC electric circuits and device. By definition, the mechanical impedance (Z) of a vibratory system is:
Z=F/v
where F is the acting force and v the response velocity.
The Z-Damper patented technology, allows impedance coupling (without backlash) between and input and an output stage that enhances the performance of any damping system. The working principle is based on the technology development of the MAGDRIVE FP7 project extended to a linear system:
A wave generator (typically input) generates a magnetic wave that interacts with an output part composed of soft magnetic materials and a linear spline. Depending on the relative number of teeth in the output and the linear spline, a reduction/amplification relationship is automatically defined with zero backlash.

For the Z-Damper, a multiplication ratio of 7 has been designed. The relationship between the input and the output stages is then defined for displacements and forces as:
F_zi=n·F_z0
X_o=n·X_i
where
F_zi is the input force,
F_zo is the output force,
X_ithe input displacement
and X_o is the output displacement,

Impedance of the input and output stages are then defined as:
Z_i=F_zi/v_i and Z_o=F_zo/v_o
And then related by the impedance coupling number as:

Z_i=n^2 Z_o
A trade-off study has been done, analysing passive, semi-active and actives technologies for vibration damping. Z-Damper technology has been selected for evaluation in this project as an outcome of this task. One of the strongest point of the technology is its temperature range of use, with the possibility to operate at temperatures up to 550ºC.
Multyphicisal Finite Element Simulations has been performed in order to design the Z-Damper: a magneto-mechanical simulation procedure has been set-up and experimentally validated in the laboratory. Prototype experimental results validated the design proccess and were used to optimize it. Structural simulations were performed in the critical design of the prototypes. Ventilation requirements were stablished using thermal simulations. An optimized fin distribution was designed to minimize the weight of the dissipator and maximize the heat transfer coefficient.
Based on this impedance coupling effect, two prototypes have been designed, manufactured and tested. A dedicated test bench has been designed, manufactured and set-up. The test-bench allows the reproduction of the CROR environmental conditions, from -50ºC to 250ºC. A ventilation system provides the ventilation requirements to the prototypes
Three main prototypes were manufactured and tested:
• Dummy of the Z-Damper: a dummy of the Z-Damper prototype has been designed, manifested and tested. The objective of that prototype has been to simulate the lateral loads on the linear bearing. Made of SmCo magnets and a steel yoke, the lateral force on the bearings is generated by contactless forces between those elements. The prototype has been used at temperature up to 250ºC and with input vibrations of 5 mm amplitude and frequencies up to 50 Hz. The prototype has been used to analyse various commercial linear bearing and to asses and adapt them to the most critical operational conditions of the Z-Damper. The coefficient of friction and the wear effects have been assessed.
• Z-Transmitter: A prototype of an impedance coupling device with multiplication ratio n=7. The device is made of NdFE 45H permanent magnets combined with soft steel magnetic material. The structural components have been manufactured in Titanium grade 5 to make the device as light as possible. The results is a device with a mass of about 9.6 kg, 500 mm in length and about 82 mm in diameter with a force capability slightly below 5 kN.
The prototype has been tested under sinusoidal input excitations of amplitudes up to 5 mm and in a frequency bandwidth from 0 to 120 Hz. It has been tested at environmental temperatures from room temperature to up to 100ºC. An average multiplication ratio of 7±0.3 Hz has been demonstrated. The device output stage has been connected to a set of external springs from 10 to 100 N/mm. A maximum input stiffness of 2200 N/mm has been measured. A video of the Z-Transmitter operating at various input excitation frequencies when coupled to an external stiffness can be watch in the following link:
In addition, the device has been tested as a tuned vibration absorber.
• Z-Damper: a prototype of a high-temperature integrated magnetic damper with a multiplication ratio n=7, 500 mm in length and about 100 mm in diameter. The prototype multiples input motion in a factor of 7. Then, power is dissipated by Eddy currents in a Electrolytic Copper tube by the motion of the fast stage magnets. The use of Sm2Co17 magnets makes possible the operation of the device from -50ºC to up to 250 ºC. The device has been tested in a frequency range from 0 to 50 Hz for various motion amplitudes and different temperatures.
A great increase on the damping was measured once the copper dissipated is assembled. Now, the Z-Damper show a supercritical damping in accordance with the simulations performed at room temperature.
When temperature is increase, the electric resistivity of copper is reduce therefore, limiting the maximum damping of the system.
A maximum equivalent viscous damping coefficient of about 40 Ns/mm for sinusoidal input excitations of 5 mm amplitude has been measured at 200ºC, a world record for any kind of damping system operating at this temperature.
CONCLUSIONS

A new technology development on vibrations isolation has been demonstrated in the FP7 Z-Damper project. The technology is based in impedance matching to optimize vibration isolation. Because no grease or lubricant is required for operation of the Z-Damper. It is able to operate from cryogenic temperatures to very hot environments (from -200ºC to up to 500ºC). The Z-Damper demonstrated an adequate performance for the CROR engine isolation requirements. Moreover, the potential applications of this technology are well beyond the scope of this project and not only in the aircraft industry, but also in the space market and many other industrial sectors.
Two prototypes and a dedicated testbench have been manufactured:
• Z-Transmitter: A prototype able to operate to up to 100ºC has been manufactured and tested coupled to external devices such as an inertial mass or a spring. The prototype has been tested in a bandwidth from 0 to 120 Hz at different temperatures. Results are very promising, especially when compared to classical tuned vibration absorbers. A reduction of about one order of magnitude in the required mass of the system has been estimated.
• Z-Damper: A prototype of an integrated high-temperature damper, able to operate in a temperature range from -55ºC to up to 250ºC. The Z-Damper is the only one of its kind with a great equivalent viscous damping coefficient up to 40 Ns/mm at 200ºC. The performance of the device has been analysed at different temperatures in a bandwidth from 0 to 60Hz and input amplitude between 0.05 and 5 mm. The prototype showed excellent damping performance at low frequencies.
The experimental results have been compared to the analytical and FEM simulation models. A user-friendly software tool has been generated which allows the user to identify the performance and characteristics of a Z-Damper depending on its vibration isolation requirements.

A European patent application has been presented.

Potential Impact:
• Potential impact and main dissemination activities and exploitation results

The Z-Damper project has allowed the development of new vibration damping technology that gives the opportunities to mechanical engineers for vibration isolation. The improvement on damping performance of the Z-Damper, based on the impedance matching, is a real breakthrough in vibration attenuation systems. It is relevant, that Z-Damper is a development that did born with another FP7 project, the MAGDRIVE project, were a rotatory magnetic gearbox was development by part of the engineering team of MAGSOAR SL and is based on a similar principle.
The Z-Damper technology will make possible vibration damping at temperatures (from -200 ºC up to 550ºC) where any other current technologies are able to operate. In addition, the impedance coupling in the Z-Damper will improve the vibration damping performance and reduce its overall weight.
Socio-economic impact will come in the following ways:
1. Impact of the technology:
a. Impact of the Technology in the Aeronautic and Aerospace Industry
The temperature range of use of the Z-Damper will allow damping of vibration closer to the source of vibrations, multiplying its effectivity. In addition, the impedance coupling effect will give further options for shock and impact isolation. Some potential fields of applications identified are: Aircraft Engines and Turbofans, Landing Gear dampers, docking dampers for Space Applications, dampers used to isolate launch loads or reduced mass tuned vibration absorbers for use in, for example, helicopters and satellites.
b. Impact of the Technology in other industrial fields
Z-damper technology will provide a useful tool for stroke and velocity amplification in servo-electrical actuators which is currently one of their main limitations. The lack of mechanical contact in this short of devices will allow them to achieve higher accelerations without damage and increase the maximum operational frequency. Z-Damper can also be used to amplify piezo-electric displacements.
The lack of backlash in the Z-Transmitter technology will give engineers a way to improve precision positioning, especially in demanding environments such as in cryogenics engineering. This will be of special interest for micro-vibration damping for example.
Vibration damping in cryogenic engineering is a frequent challenge. The cold temperatures (below -150ºC) do not allow the use of any liquid viscous damper. In addition, properties of resilient material change very significantly and suffer from creep in this range of temperatures. For those situations were damping is required at very low temperatures, like for example in cryo-pumps in the gas liquefaction industry, Z-Damper technology is call to fulfil the needs of cryogenic engineers.
In addition, Z-Damper technology will enable a reduction of cost and weight in eddy current dampers being currently used in the railway industry for high speed trains, The TSI (Technical Specifications of Interoperability) recommends that all newly built high-speed lines should make the eddy current brake possible. The Z-Damper technology will also provide a new toll for shock dampers for military vehicles and roller coasters end of stroke brakes among others.

2. Socio Economic Impact of the Exploitation
The exploitation of the technology development in the Z-Damper project is straightforward to the industry since the Consortium Coordinator (MAGSOAR) will be the solely owner of the technology patent. The socioeconomic benefit of job creation and economy activation will be produced in the European Union, especially in Spain and Germany.
Airbus potential market (2013-2032) for new aircraft was estimated in 29226 units among single-aisle, twin-aisle and very large aircrafts. This means a potential market of 4.4 trillion dollars. Z-Damper technology could be used, for example, in the future A30X airbus aircrafts, which release is planned for 2020. Commercial forecast for this plane is about 400 A/C per year. This will mean a total of 800 units per year of Z-Damper, just in this Airbus A30X. Improved efficiency in vibration isolation expected for Z-Damper technology will contribute to a direct weight, size and cost reduction of the current solutions, translating in direct cost saving. Further on, this project will have direct impact in the enhancement of the EU competitiveness against main suppliers of solutions to vibration isolation like the American company LORD
Corporation. In addition, development of Z-Damper technology in the spin-off company MAG
SOAR (fruit of other results of other FP7 projects) may be appreciated of being compliant with the current vision on enhancing the European competitiveness.
Besides the direct economic impact, environmental considerations applied to this project. Open rotor engines provide a 25-30% reduction in fuel consumption and CO emissions relative to current equivalent turbofan engines. Open-rotor powered aircraft could save around $3 million and 10,000t of carbon dioxide a year per aircraft. According to IATA (2008), aviation contributes about a 3% to the total worldwide CO2 emissions. However, IPCC alerted that, despite emissions being relatively low, ambient impact of aviation is of potential risk due to impact of different chemical compounds as NOx. For instance, the- Advisory Council for Aeronautics Research in Europe (ACARE) has set some goals for CO2 and NOx emissions as a reduction of 60% in NOx emissions for 2020.
However, in order to spread the use of CROR it is required an improvement in the vibration and noise isolation to the cabin. In this sense, Z damper provides an efficient solution in terms of weight, cost and size. Therefore, the successful development of this project will lead to a direct increase in the use of CROR engines.

3. Enabling of new technological possibilities

In the particular case of the CROR project, the success of this Z-damper project will remove its main obstacle or drawback that is the level of vibrations. If the vibrations are supressed the CROR can provide better performance than other available engines in terms of energy consumption. This is a global high-impact benefit for the whole aeronautical industry across Europe. Although it is difficult to estimate, this can represent a enabling technology for a business of many billion euro in the aeronautical sector.

Z-Damper project website address for public access:

http://magsoar.com/z-damper.html

Relevant contact details:

Scientific representative of the coordinator (MAGSOAR SL)

Dr. Ignacio Valiente Blanco
PhD in mechanical Engineering
Avenida de Europa 82, 28341 Valdemoro Spain
email: ivaliente@magsoar.com
tel.: +34 910135897

Scientific Representative of UAH (Universidad de Alcalá de Henares)

Profesor. Dr. José Luis Pérez Díaz
Department on Signal Theory and Communications
Campus Universitario, Ctra. Madrid-Barcelona, Km. 33,600, 28805 Alcalá de Henares, Madrid
e-mail: jl.perezd@uah.es
tel.: +34 918 85 65 05

Direct link to public Z-Damper Videos:

http://magsoar.com/z-damper.html

Main dissemination activities

In this project a policy of first protecting IP and afterwards publishing has been followed. Most of the results have not been published yet, waiting for the corresponding patent.

PATENT: A patent has been applied at the moment:

EP15382461: “ENHANCED MAGNETIC VIBRATION DAMPER WITH MECHANICAL IMPEDANCE MATCHING”

PAPERS

A paper has been published in a peer review, open access journal:
J.L. Perez-Diaz, I. Valiente-Blanco and Cristian Cristache, “Z-DAMPER: A New Paradigm for Attenuation of Vibrations”, Machines, June 2016.

The diffusion plan after project finished contemplates a publication of, at least, 3 more articles in first level peer review journals related to the following topics:
1. Z-Damper testbench and high temperature bearing characterization
2. Z-Transmitter Prototype: Stiffness Coupling and Tuned Vibration Absorbers
3. Z-Damper Prototype: High Temperature Magnetic Damper.
The previous publications are planned to be sent to specialized journals in vibrations and aeronautics for review before the end of 2016.

SCIENTIFIC COMMUNICATIONS

1. A paper has been sent for open access publication in Machines (http://www.mdpi.com/) the paper has been accepted after peer review. The paper can be access from: http://www.mdpi.com/2075-1702/4/2/12
2. Results of the Z-Damper Project have been presented in the Mechanism Final Presentation Days 2016 of the European Space Agency the 17th of June 2016.
3. A Z-Damper demonstrator was exposed in a Stand at the 16th European Space Mechanisms and Tribology Symposium at Bilbao Spain, in September 2015
4. Advances on the Z-Damper project were also presented in the EUROMODAL 2015 congress in June 2015.
5. A visit of University of Alcalá students of the Bachelor in Mechanical Engineering has been organized in April 2016. A demonstration of the Z-Transmitter technology and performance of the testbench was carried out.
6. Advances on the Z-Damper project were presented on the Space Robotics Symposium, organized by the University of Strathclyde will take place from 29th October to the 30th October 2015 in Glasgow, UK
7. An introduction to the Z-Damper project has been done in the UK Magnetic Society Europe Event: Magnets for a Green Future: J.L.Perez-Díaz “Superconducting Magnetic Gear, Bearings and other Magnetomechanical Devices”, 2nd and 3rd of November 2015.

Diffusion of the results will continue after the official end of the project. At least, three more scientific contribution to prestigious scientific journal is foreseen. Among the future contributions, MAGSOAR has planned to submit an abstract on the Z-Damper Results to the Greener Aviation 2016 Conference to be held in October 2016 at Brussels.

SCIENCE POPULARISATION AND OTHER DISSEMINATION ACTIVITIES

A visit to the Z-Damper testing facilities, including a demonstration of the technology in MAGSOAR facilities was organized for the students of the University of Alcalá de Henares on the 24th of March 2016. About 45 students attended the visit.

Z-Damper technology was introduced to ESA technical officers of the LEVISOLATOR project under contract with MAGSOAR SL in a visit at ESTEC facilities.

WEBSITE AND ACCESIBLE VIDEOS

Public Website: http://magsoar.com/z-damper.html

List of Websites:
WEBSITE: http://magsoar.com/z-damper.html
CONTACT DETAILS:
MAGSOAR SL_ Scientific coordinator: Ignacio Valiente, ivaliente@magsoar.com Avenida de Europa 82, 28341 Valdemoro, Spain.
UAH José Luis Perez, jl.perezd@uah.es

Final Report Summary - Z DAMPER (Z-Coupled Full System for Attenuation of Vibrations)

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