Dynamic Modelling of a Linear Friction Welding Machine Actuation System for Fault Detection and Prediction

  • Darren Williams

Student thesis: Doctoral ThesisDoctor of Engineering (EngD)


Linear Friction Welding (LFW) is a relatively new process adopted by aircraft engine manufacturers utilising new technologies to produce better value components. With increasing fuel prices and economical drives for reducing CO2 emissions, LFW has been a key technology in recent years for aircraft engine manufacture in both commercial and military market sectors. For joining Blades to Discs (‘Blisks’), LFW is the ideal process as it is a solid state process which gives reproducibility and high quality bonds therefore improving performance. The welding process is also more cost effective than machining Blisks from solid billets, and a reduction in weight can also be achieved with the use of hollow blades. The LFW process also allows dissimilar materials to be joined and a reduction in assembly time.The main aim of the research is to create a simulation model of a Linear Friction Welding machine and also apply systems thinking to fully understand the LFW process with a view to reduce total production costs. As this EngD focuses on systems thinking, a holistic approach will be used. The hard systems parts of this project will involve the mechanics of the system and understanding relationships between the key system interactions during the welding process in order to create an analytical model of the machine to use for fault diagnosis and prediction. The soft systems parts will focus on the machine users to gain an understanding of how to effectively implement the model with the process and its users.The benefits of the new model include the ability to execute it in a real- time environment with machine operation, allowing weld anomalies to be detected as (and in some cases before) they occur, as well as the monitoring of the machine’s condition. Therefore the business benefits would be realised through a reduction in machine downtime enabling the timely supply of goods providing customer value. Further benefits will be the greater understanding of the complex operation of the whole system and the welding process.Developing a robust research investigation framework, a research hypothesis is introduced and subsequent research questions are developed. Through a combination of hard system investigation using mathematical modelling and soft systems understanding through an action case study intervention, a holistic model is developed.
Date of Award26 Jun 2013
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorAndrew Plummer (Supervisor) & Patrick Keogh (Supervisor)

Cite this