CSP was invited to the NVH lab as it worked with Ford to develop a thermoset sheet molding compound (SMC) for an engine shroud designed specifically to tackle the issue of noise and vibration. Ford had determined that separating the engine compartment from passengers with two walls could help reduce traveling sound in its 2020 Ford Explorer and Lincoln Aviator. The engine shroud mimics a semi-anechoic chamber similar to those used at Ford’s NVH testing lab.
CSP ultimately settled upon a vinyl ester-based SMC material with a high fiberglass content that it engineered using a compression molding process to meet the mass/density, NVH requirements, thermal properties and structural demands of the application. The resulting engine shroud creates an air gap between the engine compartment and the steel front bulkhead. It wraps around the back of the engine to meet the stabilizing strut towers on each side of the engine bay.
This form wouldn’t have been possible using traditional materials, says Bryan Ludwig, business development director at CSP. “Because our glass fiber composite is a thermoset, it actually offers better thermal properties than a metal and can be molded thin enough to fit in the tight spaces found in the engine compartment,” he explains.
Thermal protection is critical, as the engine shroud helps dismiss the excess heat generated by the engine to protect electrical components. Of course, by using a composite material like CSP’s proprietary material within one of those walls separating the engine from passengers, the manufacturer could also reduce the weight of adding additional components. At 12 pounds, the 4-piece assembly is lighter than a similar shroud stamped from steel.
Curving a Pultruded Bumper Beam
Chevrolet calls its 2020 Stingray the fastest, most powerful base model Corvette to date, capable of achieving 0 to 60 mph speed in under three seconds. It gets that speed in part from the expansive use of lightweight materials throughout its body. Much attention has been paid in the automotive industry press to the use of an ultra-lightweight float material used to fabricate the trunk tubs and dashboard. The float material is a fiberglass and proprietary resin SMC from Molded Fiber Glass Co. that’s reportedly so light it can float in water. However, the 2020 Stingray’s multi-hollow pultruded carbon fiber bumper beam demonstrates the strength that composite materials carry with that light weight.
Photo Credit: Ford
The shape of bumper beams play a role in their crashworthiness. Researchers with the University of Turin and Michigan State University have found that in composite bumper beam development, choice of curvature radius improves vehicle aerodynamics and architecture and can contribute to vehicle safety. Changing the material and beam curvature affect the stress distribution along the beam, as well as the stress values. Getting this change right provided Grand Haven, Mich.-based composite engineering firm Shape Corp. an opportunity to innovate.