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Material Model of Case-Hardened Steels for Turbo Gear Applications

Project description

Round and round they will go, harder than steel and indefatigable

Gears are simple mechanical devices that have been used for thousands of years to transfer motion and torque among components. The gears in modern aerospace engines are no different. However, the loads they bear are tremendous. Many different processes exist to change the properties of steel. Case-hardening, often called surface hardening, is one of the most efficient ways to make steel more durable. The EU-funded MatCH4Turbo project will develop a test rig that will lead to a numerical model of case-hardening of materials' behaviours in the 'very high cycle fatigue' regime. It will enable engineers to design fail-safe case-hardened steel gears for new aerospace engines.


The objective of this joint effort between WZL of RWTH Aachen and Leibniz-IWT Bremen is to allow the extension of a fail-safe calculation of material life for future case-hardening steels considering the VHCF regime, which is indispensable for the new generation of epicyclic gear applications. To achieve this top-level objective, several sub-objectives have to be completed such as:

a) Develop fast rotating recirculating sub-element test rig for determining tooth root bending strength under reverse bending conditions;
b) Gain material data for two new case hardening steel developments in the VHCF-regime;
c) Develop and validate a VHCF material model.

With respect to the call, the consortium is able to fulfil the requirements of experience in test rig development, manufacture and instrumentation as well as a quality controlled management of facilities and processes for a recirculating rig testing (WZL). The gear test processing includes all aspects of test gear design, instrumentation measurements, measurement uncertainties and limitations. Especially due to the fact, that WZL has a gear testing environment that is already officially approved by aircraft engine producers a high potential for a successful dissemination of the project results into industry is expected. The methods utilise FE-based strength analysis in weakest link models and analysis to ISO 6336 standard (WZL). The consortium is capable to characterise the material and failure mechanisms by residual stress measurement by X-ray diffraction, electron microscopy, and metallography at highest standard as well as to describe material failure phenomena in the VHCF regime through theoretical models (Leibniz-IWT). Based on the combined experiences the collaboration of WZL and Leibniz-IWT allows for a successful derivation of VHCF material model for case hardened gear steels for application in an epicyclic power gearbox.


Net EU contribution
€ 1 943 725,00
52062 Aachen

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Nordrhein-Westfalen Köln Städteregion Aachen
Activity type
Higher or Secondary Education Establishments
Total cost
€ 1 943 725,00

Participants (1)