By: Bill Bregar
June 4, 2014
ATLANTA — Street Shark. The name says it all for the award-winning polyurethane car hood from Frimo Group GmbH on display at JEC Americas.
Most car hoods are smooth. The Street Shark has a textured finish, which actually cuts wind resistance, as well as reducing weight. The hood netted an Innovation Award in the automotive category at JEC Americas, the composites trade show in Atlanta held May 13-15 at the Georgia World Congress Center.
If you look closely, it resembles thousands of tiny bird prints. Actually, Frimo marketing manager Sven Garcia Alba said, the surface is that of a shark skin — and Frimo used skin from an actual shark to design the aluminum mold for the part, made by resin transfer molding.
“In Germany, you have to wait until a shark in a zoo dies, because you have no way of importing it, the shark skin,” Alba said.
Frimo ended up using a small section of the skin of the shark, a fish that knifes through the water, thanks to a uniquely textured surface.
“We made a mold of silicone out of this, then transferred it to the final mold. The final step was enlarging the structure,” he said.
Real shark skin feels like fine sandpaper, but the hood texture had to be enlarged to get the same effect in the air, which has lower density than water. Other than the larger size, Alba said, “It’s exactly the same structure of the shark that died.”
Alba, who was stationed at the Street Shark display during the show, repeated his explanation countless times: It’s a case of industry learning from nature. It’s scientific. And it’s cool: Prototypes are used on special modified versions of two sports cars, the Porsche 911 and a BMW Z4. The special BWM Z4 has Street Shark on the roof and hood. The Porsche, now being made, will have a hood with the material.
The PU hood weighs about four pounds less than aluminum hoods used on those two cars.
“It’s lightweight and it reduces drag,” Alba said.
The reduced drag is like the puck on an air hockey game — air floats over the surface without touching the hood. Even better, the “skin” helps the air actually flow faster over the surface.
“The extruder which the Shark has, builds a very small turbulence on top of the surface, which builds a kind of a layer on this top,” Alba said. “Flowing air is not touching the part itself anymore — like going over wheels.”
To the novice, the idea of a textured surface being more aerodynamic than a smooth one seems counterintuitive. But Alba said engineers have known about this principle since the late 1970s. The problem is they only could use textured foils, laminated onto a part. But the foil does not have undercuts, and it could separate away from the part.
“The foil also has the disadvantage that it has to be laminated onto something in a second process step. And here we don’t have to. The part gets out of the mold just like this,” he said.
Frimo uses in-mold coating, because if you paint the part after it gets molded, the paint can cover up the shark texturing. Polyurethane is molded over a honeycomb structure, and Alba said PU flows well, much better than epoxy resin, another two-component plastic. That allows you to use a smaller, less-expensive molding machine, with less pressure. And you can tailor the polyurethane recipe to fill out the part better.
Frimo, based in Lotte, Germany, can produce very small series of parts. But Alba said the company’s goal is to sell the technology to automakers and suppliers, so they can make their own.
“This could be the standard in the future for race cars,” he said.
Alba said Frimo officials also are targeting other markets.
“We think this is really a good solution for race cars, planes and ships in the future, to get faster or to get better fuel efficiency, as the drag is reduced by the structure from the surface,” he said.
JEC Group, an international organization dedicated to the composites industry, announced Frimo as the automotive winner at the Atlanta conference. Street Shark was one of 10 JEC Innovation Awards recognized at the Atlanta show floor.
TSE Industries Industries Inc. of Clearwater, Fla., won the raw materials category for bio-based EcoSpray 550 urethane reinforcing resins made from natural renewable oils, for spray layup.
Stäubli GmbH of Bayreuth, Germany, earned the reinforcements category prize for its double rapier weaving machine for the economical production of three-dimension weaves, which can be locally adapted, to make reinforcing fabrics. Unlike conventional weaving machines, two or more grippers can be used for the weft insertion, enhancing productivity.
Plataine Technologies (USA) in Waltham, Mass., won in the software category for its software that bridges the gap between computer aided design and enterprise resource planning.
Germany-based aerospace company EADS earned the award for processing category, for its novel fiber patch preform (FPP) process that combines a material supply unit, a pick-and-place robot and a tool manipulation robot. The machine continuously manufactures fiber cuttings that are then picked, placed, draped and fixed on a preform tool, to create a dry-fiber preform.
Technical University of Braunschweig, Germany, won the automation category for its FormHand process. It uses a six-axis articulating robot that places the material on a preforming device, and the airstream from the gripper determines whether the granules within the cushion can move freely or jam and solidify. This allows specific forming or draping of the textile into the mold, for RTM.
The ballistics category winner went to two French companies, PPE and Cedrem, for the BBOX high-energy absorber for the defense market. The composite structure protects vehicles and buildings from detonation or flying debris from improvised explosive devices. It uses “oriented bridge” composites that absorb energy when the spacers rupture.
The construction category went to three companies: Kompetenzzentrum Holz GmbH of Austria, Johns Manville in Germany and FunderMax GmbH of Austria. The part is a non-combustable composite panel for decorative facades. The project required expertise in material science, laminate production and surface technology.
The first ukulele made of natural fiber composites netted the sports and leisure category award for Swiss materials company BComp and U.S. partners, Blackbird Guitars and Lingrove Composites. Lingrove combined BComp’s low-crimp ampliTex-brand flax with its cashew nutshell-based bioresin make a novel, high-performance pre-preg called Ekoa. The material combines low weight, high strength and toughness with sold quality.
Blackbird Guitars expects to sell several hundred of its Clara ukuleles by the end of 2014.
Owens Corning Corp., operating in France and the U.S., picked up the wind energy category award, for wind turbine blades made for WINDnovation in Germany. The design of lighter wind turbine blades helps reduce costs, and more energy can be produced if the blade delivers more torque with little wind, or of the turbine can run longer at stronger wind speeds. Owens Corning used its new Ultrablade unidirectional and multiaxial glass reinforcement range of fabrics. The stiffness and strength of the new reinforcement were improved by more than 15 percent.