Community Research and Development Information Service - CORDIS


RAAI Report Summary

Project ID: 674231

Periodic Reporting for period 4 - RAAI (Whole Life Rail Axle Assessment and Improvement Using Ultrasonic Phased array and Corrosion Inspection Systems)

Reporting period: 2017-06-01 to 2017-11-30

Summary of the context and overall objectives of the project

The objective of the RAAI project is to develop novel NDT solutions for the corrosion assessment and crack detection as well as reliability software for high cycle variable amplitude corrosion fatigue of rail axles. Currently, the most sensitive non-destructive testing methods for inspection of rail axles are surface inspection methods designed for crack detection. These don’t typically attempt to measure corrosion. Current trend is for axles to be withdrawn from service long before their design lives due to suspected corrosion developed on the surface. The decision is taken without the full knowledge of the way in which the failure will result from.

RAAI will develop two novel methods:

1. Corrosion assessment,
2. Phased array ultrasonic.

The first method assesses the effect of corrosion on high-cycle fatigued components such as the axle and evaluates its remnant life thereby improving the sentencing of corroded axles. The second method is specific to hollow axles of high speed trains and aims to improve the speed of the inspection (by 75%) and improve crack detection reliability (almost 100% with a crack of 2-3 mm depth) without dismantling the wheel-set and with minimum time for inspection. The primary impact is to improve the competitiveness of the SMEs by enabling them to provide NDT solutions to reducing the cost of and improving the safety margins of rolling stock operation

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

"We built a comprehensive review on current knowledge to develop the detailed specifications of the corrosion assessment system, the ultrasonic phased array system and the inspection interval software. Based on it a functional design of the prototype was developed.

A complete overview and a detailed description of the available test axles and the axles which have to be procured for the project was produced. The preparation of new test axles by including cracks from fatigue tests was planned and the raw axles for these tests were provided.

Based on a review of the WOLAXIM project the specifications for the corrosion inspection system in the RAAI prototype were defined. Possible changes from the WOLAXIM project for further optimization of the construction, to achieve a higher scan speed along and around the axis, were investigated.

The specifications of the phased array system in the RAAI prototype were defined. Possible changes of the phased array probe from the WOLAXIM project for further optimization were investigated.

The project website was installed under

For the new system an automated data collection and image analysis probe with a related scanning system and a data acquisition and interpretation software was developed. The new system was designed and the manufacturing was completed.

The optimisation of the construction of the phased array probe, to achieve a higher sensitivity, was finished. The dependency of the incidence angle on the sensitivity especially in the transition regions was investigate theoretical by modelling and tested in laboratory trials. Therewith the angle was optimised for a better detecting of flaws in the curved surface with an acceptable signal-to-noise ratio at the plane surface of the axle.

Improved software modules which will provide the reliability of the axle under high cycle variable amplitude (HCVA) fatigue and corrosion conditions was developed for different materials. This includes the preparation and inputting of high cycle load spectra and the inclusion of the crack growth equations. The modules can be easily parametrised and applied by a new graphic user interface (GUI). It provides a simple evaluation of the calculated results for the predicted lifetime and the related inspection interval.

At the special meeting of ESIS TC24 in October 24th/25th 2016 in Leoben (Austria) the planned approach of the RAAI system and the first results of the project were presented to a technical audience. The posters were uploaded on

An ESIS TC24 workshop ""Integrity of Railway Structures"" was held in Wittenberge Germany, 25th and 26th of September 2017. Several presentations about the RAAI project were delivered. The presentations are available at:

Further presentations of the project results are planned for the 10th Symposium for NDT in Railroading in March 2018 in Wittenberge, Germany.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The European rail network is aiming for an expansion of passenger and freight traffic by 2020. It’s supported by a mandate given to the European rail sector in 2011 by the European Commission to shape the future of transportation in Europe. In order to achieve this, increased reliability and availability of rolling stock is necessary whilst maintaining the same or a better level of safety.

The RAAI project will result in a group of novel devices and a software module for the inspection of rail axles. The project is closely related to Horizon 2020 dedicated SME Instrument topic “IT-1-2014: Small business innovation research for transport” to have the capacity to deliver the best products and services, in a time and cost efficient manner, in order to preserve its leadership and create new jobs and to tackle the environmental and mobility defies. The SMEs in the consortium are all high technology SMEs who jointly form a supply chain with the following capabilities:

+ To engineer RAAI system so that it is (i) improved and reliable and (ii) economically viable for the rail operators;

+ To manufacture and market the system;

+ To provide on-site services with the system.

The RAAI system will have impacts on the European rail industries. Firstly, it will make inspection and assessment reliable and cost-effective and secondly it will improve the operation of the European rail industries. We will endeavor to enhance the two novel methods (phased array system for detecting cracks in hollow axles and corrosion inspection system for measuring corrosion assessment in rail axles) developed in the WOLAXIM project, to reduce the inspection cost and time, to increase the reliability of corrosion assessment thereby decreasing the sentencing of the axles, etc.

The results of the RAAI project will be used in the rail industry which will offer higher probability of detection (POD) of corrosion and cracks, improved and sustainable inspection of rail axles and savings of inspection cost through 75% reduction of inspection time and at least 20% of savings of rail axles and thus more economical for rail operators. Developing a complete system ready for commercialization after the end of the project will increasing profit and business growth for the consortium’s SMEs from sales of the novel corrosion assessment system, phased array ultrasonic technology as well as software development.

To ensure a maximum impact of the RAAI project, we will employ a multi-channel dissemination strategy to gain maximum visibility including academia, the industry, end-user organizations, policy makers, and the general public. The dissemination strategy will focus on:
+ Distributing relevant results among scientific communities;
+ Propagating research results in the form of new technologies, prototypes, and interactive concepts to the respective industry branches and public and corporate audiences;
+ Organizing seminars and workshops to disseminate knowledge on the methodology and technology used
+ Informing the general public of the project results by means of a website

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