Deformation and Fatigue Behaviour of Aluminium Alloys for High Specific Power IC Engine applications

Elanghovan Natesan, Visiting Researcher at Engineering Materials​ IMS, defends his doctoral thesis.
Public defence
2020-10-29 09:00 - 13:00
Examiner: Christer Persson, IMS
Opponent: Dr. Svjetlana Stekovic, Linköping University, Sweden

Popular science description
The natural tendency of metals is to expand when they are heated and contract again upon cooling. But what happens if this free expansion and contraction of the material is restricted? Actually, we stress the material and induce permanent shape change in the structure by deforming it plastically! Furthermore, when such heating-cooling cycles are repeated in structures that are inhibited against free expansion or contraction, we induce damage in the metallic material. Every time we start our cars, such loading is experienced by certain parts of the car engine. In cold climates, temperatures range from sub-zero to over 200 °C, rapidly increasing during start-up and cooled back again upon engine turn off. The number of such start-stop cycles have been increased owing to recent trends in vehicle electrification. This places even higher demands on the engineers to design structures that can avoid premature failures. For a cost and time efficient product development process, computer aided design methods are used which rely on accurate mathematical models that can predict the material response to applied loads and foresee any damage caused in the material.
In this thesis, we study the various factors that affect the material deformation and fracture behaviour at the temperatures expected in vulnerable parts of combustion engines. This enables us to develop reliable numerical models that can aid the design and development process and minimize the need for expensive and time-consuming physical testing. The results of the study enable us to better understand how the material behaves under loading and will help us design products that have a predictable performance and thus contribute to a successful electrification experience!

Published: Mon 12 Oct 2020.