Click here to sign in with or

by Jesper Bruun, Aarhus University

Imagine a velvety, soft material that is extremely light, but also strong enough to stop a bullet. This is close to a description of ultra-high molecular weight polyethylene (UHMWPE), a super-plastic material commercially known as Dyneema or Spectra, which is already taking over from the para-aramid fibrous material, Kevlar, in e.g. bullet-proof jackets.

There is also much need for the super material in many other applications than body armour, and therefore researchers have now set up guidelines and failure maps for use of the material in joints with steel bolts. The research team is being led by Simon Skovsgård, Ph.D. and MSc in engineering at the Department of Engineering, Aarhus University, and Professor Norman Fleck at the University of Cambridge.

The results have just been published in the International Journal of Solids and Structures.

"The tests we've done showed that the material began to deform at the joints, but the fibres weren't broken. This is interesting in relation to other popular composite materials, such as carbon fibre composites, which snaps suddenly. Here, although we can tear the material, it's really difficult to actually break the fibres," says Simon Skovsgård.

UHMWPE consists of extremely long chains of polyethylene (PE). And these long chains strengthen the intermolecular interactions of the substance and enable the material to transfer stress loads effectively to the polymer skeleton.

This means that UHMWPE fibres have an incredibly high tensile strength compared to many other thermoplastics, and this also means that the material is much stronger than steel in the fibre direction. The tensile strength of high-strength steel is approx. 900 MPa, but in order to break the fibres in UHMWPE, you need approximately 3000 MPa.

"UHMWPE fibre plates are a collection of these incredibly strong fibres. It's almost impossible to extend and break the fibres, but if you twist or shear the material, it is soft. This combination makes it easy for the material to absorb energy," says Simon Skovsgård.

The new research results are good news for the commercial use of UHMWPE, which is increasingly being introduced in the shipping industry in containers, ropes and nets, as well as armour for vehicles and personnel and in the textile industry. So far, there has been no experience with using the material combined with other materials. Explore further Army research looks at pearls for clues on enhancing lightweight armor for soldiers More information: S.P.H. Skovsgaard et al, Load transfer within the bolted joint of a laminate made from ultra-high molecular weight polyethylene fibres, International Journal of Solids and Structures (2019). DOI: 10.1016/j.ijsolstr.2019.08.014 Provided by Aarhus University Citation: New research identifies the strengths and weaknesses of super material (2019, October 1) retrieved 31 July 2022 from https://phys.org/news/2019-10-strengths-weaknesses-super-material.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

More from Physics Forums | Science Articles, Homework Help, Discussion

Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form. For general feedback, use the public comments section below (please adhere to guidelines).

Please select the most appropriate category to facilitate processing of your request

Thank you for taking time to provide your feedback to the editors.

Your feedback is important to us. However, we do not guarantee individual replies due to the high volume of messages.

Your email address is used only to let the recipient know who sent the email. Neither your address nor the recipient's address will be used for any other purpose. The information you enter will appear in your e-mail message and is not retained by Phys.org in any form.

Get weekly and/or daily updates delivered to your inbox. You can unsubscribe at any time and we'll never share your details to third parties.

Medical research advances and health news

The latest engineering, electronics and technology advances

The most comprehensive sci-tech news coverage on the web

This site uses cookies to assist with navigation, analyse your use of our services, collect data for ads personalisation and provide content from third parties. By using our site, you acknowledge that you have read and understand our Privacy Policy and Terms of Use.