Although welding has been used for about 100 years, and welding technology has evolved considerably, the weld is still often a weak link in a design. This particularly applies to structures subjected to rapidly varying loads, so-called fatigue. Examples are in particular vehicles of various kinds. To develop more environmentally friendly vehicles, you need to use steel with increasing strength and which also weigh less. Unfortunately, the welds limited fatigue strength often limit the ability to use high strength steels.
In a dissertation by Erik Åstrand from University West describes how the manufacture of welded structures subject to fatigue can be improved for the future. The premise is that a good weld in the future to create added value by offering a lower cost, longer life and higher load capacity. Erik Åstrand has in his research examined how by varying the welding requirements and welding procedures based on load case for the weld can get a better result.
- An important conclusion regarding custom welding procedures and related requirements relate to prioritize what is important and to prioritize off what is not important. It is difficult to produce welds having good properties throughout. In theory, it is often relatively simple changes, but in practice it is very challenging to implement.
For the benefit of Volvo
The results show that the welding standards and quality levels need to be updated as well as the design rules, as they are not suited for welding with a high fatigue strength. A major challenge is to implement a new approach where welds are specified and produced with the new requirements and different levels of quality.
- An important role of the Academy is to contribute to a scientific framework for the welds of high quality with a clear link to its life span. This can then be used for design of welded structures with a lower weight. The key is to develop new requirements and guidelines based on the welding procedures that provide excellent properties instead of the present situation when the whole system is based on the welding procedures developed without any connection to fatigue, says Erik Åstrand, who during his postgraduate been an industrial PhD student at Volvo CE.
The connection to Eric's job at Volvo CE is clear and he could see that his research can affect parts of the developments in Volvo:
- There is a big potential in improvement for reduced weight, increased load, reduced production costs and increased productivity for welded structures with fatigue loading. Of course, that is the positive results for an industry like Volvo, says Erik Åstrand.
Contact: Erik Åstrand, 070-0897573, email@example.com
Thesis: "A Framework for Optimized welding of fatigue loaded structures"