Velcro on steroids

Researchers design steel analog of well-known fastener

Hook-and-loop tape is the generic name. But everyone knows the plastic fastener that can be reused and repositioned endlessly as Velcro. Now, German engineers have developed industrial-grade analogs for automotive and other applications. Made from steel, the newly patented fasteners can operate at temperatures as high as 800° Celsius and at tensile loads of up to 35 metric tons per square meter.

VELCRO OF STEEL When pressed together, barbs on the upper tape of a new steel fastener will lock into tiny metal catches on the bottom strip. The fastener can withstand exposures to high temperatures and strong chemicals. J. Mair/Technical University of Munich

Industrial companies approached the Technical University of Munich’s Institute of Metal Forming and Casting four years ago about developing the new connectors. They’re patterned on the burrs that some plants have evolved to adhere to the coats of animals for seed dispersal.

In the new Metaklett fasteners, rows of protruding, gently barbed points cover one surface of a perforated metal strap. A second strap houses rows of catches that stand poised to lock any barbed points in place. Pulling the paired straps apart releases the barbs. But just as with Velcro, the locked straps won’t loosen and slide with strong shear forces.

Josef Mair, a mechanical engineer who recently took over as head of the team that helped develop the university’s working prototypes, says the connectors could be used in automotive systems — such as near exhaust pipes where extreme heat and corrosive gases might degrade other fasteners. The strips could also be used to snap aluminum siding onto homes or for attaching curtains in hospitals where fasteners are regularly sterilized with strong chemicals.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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