Doctorate CIFRE – Development of a tool for predicting the torque-tension relationship for screwed assemblies (m/f). à Toulouse

Airbus is a global leader in aeronautics, space and related services. In 2017, it generated revenues of € 67 billion and employed a workforce of around 130,000. Airbus offers the most comprehensive range of passenger airliners from 100 to more than 600 seats. Airbus is also a European leader providing tanker, combat, transport and mission aircraft, as well as Europe’s number one space enterprise and the world’s second largest space business. In helicopters, Airbus provides the most efficient civil and military rotorcraft solutions worldwide.

Our people work with passion and determination to make the world a more connected, safer and smarter place. Taking pride in our work, we draw on each other's expertise and experience to achieve excellence. Our diversity and teamwork culture propel us to accomplish the extraordinary - on the ground, in the sky and in space.

Aeronautical structures are mainly constructed using bolted assemblies. The current means of installing the fasteners permits good control of the tightening torque, but can result in uncertainty as to the pre-tension induced in the fastener. However, the service life of the assembly is directly related to the pre-tension applied in the fastener. Good control and monitoring of this pre-tension would allow AIRBUS to improve the service life of these devices and optimize maintenance phases, which may require long periods of downtime of the device. The pre-tension of a fastener is dependent on many parameters such as the nature of the joint, the materials used, the surface treatments and the tightening torque applied to the fastener. A better knowledge of the technological issues related to screw assemblies, as well as the interaction of prestressing with the conditions of aeronautical assemblies, will allow an overall control of this process in an industrial context as well as a reduction of risks during the production start-up phase. This thesis is part of a global project to create a tool to predict the torque/tension relationship of fasteners, in order to optimize the AIRBUS standards for tightening torques to be applied on aircraft, and to be able to respond quickly to the various problems concerning the torque applied in production. These data will also allow a better understanding of the problems of spontaneous loosening that can occur on the fasteners. Initially, an experimental approach will be carried out with torque/tension tests to highlight the evolution of the pre-tension according to the geometric and technological parameters of the assembly and the implementation of specific experimental procedures to evaluate the robustness of the pre-tension process in an industrial application context. Characterization tests on friction will also be carried out at the various interfaces. Then we will be able to set up a predictive and optimization tool dedicated to our wide range of screw/nut combinations in materials, diameters, surface protection on these and the variants of use. This tool could also make it possible to establish the link with the clamping devices to be deployed according to the industrial constraints and the areas used (composite and metallic).

• Creation of an analytical prediction tool
• Carrying out torque and preload tests
• Management within the framework of the R&T project
• Management of the manufacture of coupons and tools
• Presentations during conferences and publications.

This job requires an awareness of any potential compliance risks and a commitment to act with integrity, as the foundation for the Company’s success, reputation and sustainable growth.

• Advanced English
• Advanced French
• Simulation tool: Abaqus good level
• Engineer with broad skills, based on the complementarity of multidisciplinary scientific and technical knowledge in the field of Mechanical and Industrial Engineering.