Textiles for lighter cars

The material needs to be lightweight, effective and just as strong as those that are currently used. Lars Brandin, Tommy Martinsson and Kristian Rödby, knitting technicians at the University of Borås’ School of Textiles, are used to being challenged by various companies to come up with new ideas, but this was the first time they had worked with the steel industry.

“Who would have thought that textiles could be used in the steel industry?” asks Kristian. “But that’s exactly what we’re doing here at the School of Textiles.”

The project, called Metmask, is a collaboration between the School of Textiles, Swerea IVF, Gestamp HardTech, Lamera, Outokumpu Stainless and Inkubatorn i Borås, and has received SEK 2.3 million in funding from VINNOVA. Project manager from Swerea IVF: Åsa Lundevall. Project manager from the School of Textiles: Nils-Krister Persson.

The brief was to develop a knitted laminate to join together two sheets of metal. Since the laminate needed to be both light and strong, it was hard to find the right bonds to meet the requirements.
“It’s certainly been a challenge,” says Tommy. “I’ve even rebuilt a machine to make it possible.”

For Gestamp HardTech, one of the companies involved in the project, it is important to be able to meet car manufacturers’ demands when producing crashworthy automotive components.

The focus has been on examining a three-layer sheet laminate and replacing it with a metal-knitted fabric. The layered structure of the laminate with the knitted metal at its core makes it possible to reduce the weight compared with an equivalent sheet of metal. The sheet metal, metal thread and joining method have been adapted to cope with demanding environments. A number of different tests have been carried out during the course of the project, and various forms have been developed and evaluated. Mouldability, 3D scanning, surface assessment and material characterisation are some of the parameters against which the laminate is tested. A parameter study is also carried out to analyse which parameters in the laminate have the greatest effect on the end-result and what is most relevant in terms of continued optimisation.

“We’re evaluating different alternatives to reduce car emissions in the future,” explains Gestamp HardTech’s Lars Wikström. “They have to become lighter – that’s a requirement for the whole industry. A textile solution sounds promising.”

The textile laminate concept also means that it can easily be introduced into existing production without having to make costly investments or expensive changes to production.
“Throughout, we’ve adapted manufacturing for a circular knitting machine to make it as profitable as possible for manufacturers,” says Lars.

Bildtext: Two sheets of metal are joined together, with the textile laminate discernible between them.