Noise and vibration (N&V) represent one of the biggest environmental challenges for the railway. The target of this work area is to reduce the exposure to noise and vibration related to the railway sector in Europe. Population in the vicinity of railways do not accept the increasing N&V annoyance while on the other hand a shift to rail-traffic is important for environmental reasons.
Exterior Noise: In order to ease vehicle certification and reduce the associated cost and time expenses without penalising the real vehicles noise performance, virtual certification can play an important role in the future. Thus, current exterior noise simulation tools require further research and validation in order to ensure that the procedures and methodologies applied, and the results obtained represent the noise performance the real train will have.
Additionally, current noise measurement procedures lack the possibility to accurately separate noise sources on pass-by noise tests, and do not cover the common vehicle scenarios including different track types. Source separation is relevant both for vehicle validation and for source ranking prior to mitigation measure implementation, and the improvement of separation techniques shall finally lead to more flexibility, better comparability and hence a better vehicle characterization in current homologation procedures.
New Technologies: Noise control of railways is a challenge also from a comfort point view of the passenger. New and innovative solutions are required to match and exceed the development of passenger comfort and acoustic performance in other modes of the transport such as cars, busses and aircraft, in the future.
In order to address the challenges described above, the proposed research shall address the work- streams described below, in line with the Shift2Rail Multi-Annual Action Plan (MAAP).
Work stream 1: Exterior noise simulation tools
The objective of this work stream is to improve exterior noise at standstill and pass-by simulation capabilities based on existing tools developed in the complementary action and results achieved in the European projects ACOUTRAIN 53, Roll2Rail 54 and FINE1’s55 .
Proposals should provide modelling of exterior noise adding together noise sources placed on different parts of the train to simulate the resulting noise levels. The activities in this work stream are expected to focus on the following areas:
Definition of the strength and directivity of each source: Measure or simulate sound power and directivity or use existing data from measurements and/or simulations data base for 5 different noise sources of a rail vehicle. These sources shall include sources located on the vehicle roof, on its underframe and on its bogie (traction motor). Noise sources contributing to the exterior noise of a standstill and a pass-by vehicle (except rolling noise) shall be considered (a vehicle with a maximum speed, lower or equal to 160 km/h, on a free field and ballasted track shall be considered for the pass-by scenario).
53 http://www.acoutrain.eu/?page_id=883 54 http://www.roll2rail.eu
Represent the strength and the directivity of the source as an equivalent source improving the methodology from ACOUTRAIN (superposition of simple sources 56) or with new modelling techniques and validate the representation. Note that the noise generating phenomena of the equipment itself does not have to be modelled. The modelling shall follow requirements proposed by the complementary Members project. Basic requirements for source characterization and ranking of relevant source types can be found in FINE 1 Deliverable D8.1 “Characterisation and specification requirements” 57.
Define integration effects due to installation of the source on the train by measurement and/or calculation. Integration effects are changes of effective sound power, radiation characteristics or operating condition once the sources are installed on the vehicle in comparison to e.g. a test bench or a pure source simulation (integration effects shall consider equipment mounted on the vehicle roof, on its underframe and on its bogie, as well as the presence of skirts and fairings). Simulation methodologies for integration effects shall be developed and it is of special interest to have a general method and avoid relying on costly measurements that represent only one case. All simulation results need however to be validated by measurements. For the validation of the integration effects of bogie-mounted equipment, a standstill vehicle can be considered and either real equipment or known noise sources (such as omnidirectional loudspeakers) can be used.
Simulate the added effect of all the sources together for a vehicle at standstill and on a pass- by. Propose a methodology to estimate the uncertainties of a complete simulation process (input data, source model and propagation model uncertainty) for constant speed pass-by and standstill cases. This uncertainty assessment methodology shall be applied to reference cases proposed by complementary Members project.
Knowledge and experience of the ACOUTRAIN 58 type of approaches, of exterior noise modelling according to standard ISO3095:2013 and of the state of the art of exterior noise modelling and installation effects are hence required.
An indicative scheduling of the deliverables is suggested below 59:
State of the art, strategy for improved exterior noise modelling and source representation - M9;
Description of improved equivalent source models based on sound power and directivity including integration models and validation testing campaign proposal - M18;
Conclusions and validation test results for the models developed - M30;
Uncertainty analysis - M33.
Work stream 2 - Pass-by noise source separation
The objective of this work stream is to develop novel and innovative techniques to get the sound power level and directivity of the different types of noise sources during pass by at constant speed of a train.
59 The scheduling of the deliverables is provided to facilitate the complementarity with the CFM actions and it is not binding. Additionally, each deliverable may have some flexibility in the scheduling.
The techniques proposed shall present improvements and benefits in comparison to separation techniques used in the past. The type of sources to be considered shall include aerodynamic sources, traction noise sources as well as rolling noise (rolling noise can be considered as an entity, with no need to separate track noise from wheel noise). Any methodology proposal shall be capable of providing the sound power and directivity of the each of the separated sources at least in 1/3 octave band resolution and may include improved beamforming technologies. The complementary member project will define two vehicle scenarios and the methods proposed should be agreed with the complementary Members project
The techniques developed shall be validated and assessed for uncertainties for each vehicle scenario separately on test campaigns to be organised by this open call. The complementary Members’ project will define and give access to vehicles and tracks to be used for this purpose. An analysis to quantify the uncertainties of the techniques developed shall be included. A detailed theoretical background and the validation test results shall be provided to the complementary project for their analysis.
Knowledge and field experience of state of the art of source separations techniques and methodologies types from Roll2Rail project is required 60
An indicative scheduling of the deliverables is suggested below 61:
State of the art, strategy for new separation techniques, M9
Innovative separation techniques: theoretical description and validation testing campaign
Innovative separation techniques: validation test results, M27
Work stream 3: Separation of track noise versus vehicle noise
The objective of this work stream is twofold: simplify and enhance methodologies for separation of rolling noise with the track versus vehicle part and extend their validation and data collection to several vehicle scenarios.
The most promising separation techniques analysed in the project ROLL2RAIL62 are to be taken as a starting point for further development (e.g. ATPA, PBA, TWINS based transfer function methods, improved beamforming and/or hybrid methods63). The most promising methods available should be analysed to clarify strengths and weaknesses for simplification and define uncertainties in view of using them for authorisation procedures in the future as well as from a scientific point of view to assure increased knowledge of the basic physics involved in rolling noise generation and separation. Roughness separation between wheel and rail is expected.
Furthermore, the method shall allow transposing pass-by data obtained on one track to another track of different roughness and track decay rates. The method should provide track noise in parts of vertical and lateral rail vibration with high accuracy. Specification of requirements for the development together with three vehicles scenarios to be considered will be provided by the complementary project.
61 The scheduling of the deliverables is provided to facilitate the complementarity with the CFM actions and it is not binding. Additionally, each deliverable may have some flexibility in the scheduling.
63 Roll2Rail Deliverable 7.4 http://www.roll2rail.eu/Page.aspx?CAT=DELIVERABLES&IdPage=45291e18-8d8f-4fd6-99f8- 5d4b7a519b9c
The separation techniques developed shall be validated for each vehicle scenario separately on test campaigns. The complementary project will define and give access to vehicles and tracks to be used for this purpose. An analysis to quantify the uncertainties of the techniques developed shall be included. A detailed theoretical background and the validation test results shall be provided to the complementary project for their analysis.
Knowledge and field experience of state of the art of rolling noise separations techniques and methodologies types from Roll2Rail project is required 64
An indicative scheduling of the deliverables is suggested below 65:
a) State of the art, strategy for enhancing separation techniques - M9;
b) Track versus vehicle separation and transposition techniques including theoretical description
and proposal for full scale validation test campaign - M15;
c) Track versus vehicle separation and transposition techniques conclusions, recommendations
and validation test results - M30.
Work stream 4 – New Materials and Concepts
The objective of this work stream is to use new and innovative approaches to improve the acoustic design for the interior noise on future rolling stock.
The activities in this work stream are expected to focus on the following areas:
Initial feasibility studies on a number of innovative ideas and approaches for future noise abatement and sound quality improvements in the compartment of trains e.g. new materials and methods for transmission loss and absorption or sound quality control or other novel concepts. The feasibility study shall consider the current state of the art methods and needs of the complementary project and shall be based on agreed criteria assessment between the two complementary projects;
Select two of the most promising design approaches from above in agreement with the complementary project;
Acoustic performance characterisation by simulation for the baseline design of the selected concepts;
Acoustic performance characterisation by simulation for new design concepts (including new materials simulation and/or measurement characterisation);
Validate new concept by measurement (measurement/test specification in agreement with the complementary project).
An indicative scheduling of the deliverables is suggested below 66:
a) Initial feasibility study of new concepts and approaches - M8;
65 The scheduling of the deliverables is provided to facilitate the complementarity with the CFM actions and it is not binding. Additionally, each deliverable may have some flexibility in the scheduling.
66 The scheduling of the deliverables is provided to facilitate the complementarity with the CFM actions and it is not binding. Additionally, each deliverable may have some flexibility in the scheduling.
b) Acoustics performance characterization of baseline and new design variants (simulation) - M 14;
c) Validation of acoustics performance characterization of new design variant (measurement/test) - M 30.
Foreseen achievable Technology Readiness Level: TRL 3 / 4
As specified in section 2.3.1 of AWP 2019, in order to facilitate the contribution to the achievement of S2R objectives, the options regarding 'complementary grants' of the S2R Model Grant Agreement and the provisions therein, including with regard to additional access rights to background and results for the purposes of the complementary grant(s), will be enabled in the corresponding S2R Grant Agreements.
The action that is expected to be funded under this topic will be complementary to the actions that are expected to be funded under the following topics:
S2R-CFM-CCA-01-2019: Integrated mobility management (I2M), Energy and Noise & Vibration.
The action stemming from this topic will also be complementary to actions carried out within the following projects:
FINE-1 (GA 730818).
All technical results from all the work streams of this topic should be provided to the complementary
- Reduction on rail vehicles noise validation lead time and cost;
- Reduction of requirement non-compliances at product delivery;
- More precise and better-founded requirement definition for equipment suppliers, reducing time
- Lower operators’ track occupation for testing;
- Better understanding of noise contributors exterior noise;
- Higher comparability and reproducibility of pass-by measurements;
- The new assessment method will allow silent vehicles to show up and will stimulate low noise
- A better basis for possible noise dependent track access charges;
- Reduce the need of a TSI-compliant test track (e.g. slab track is also possible without high risk);
- Availability of new, innovative and validated design solutions for interior noise control. Type of Action: Research and Innovation Action (RIA)