Reducing Automotive Interior Noise with Natural Fiber Nonwoven Floor Covering Systems

Abstract

Eliminating unwanted noise in passenger compartments of vehicles is important to automobile manufacturers. The ability to reduce noise inside the vehicle enhances the perceived value of the vehicle to the consumer, and offers a competitive advantage to the manufacturer. Several methods are presently employed to reduce noise and its sources, one of which uses sound-absorbing materials attached to various components such as floor-coverings, package trays, door panels, headliners and trunk liners. Natural fibers are noise-absorbing materials that are renewable and biodegradable, making them an effective choice for the automobile industry. Floor coverings using natural fibers (kenaf, jute, waste cotton, and flax) in blends with polypropylene (PP) and polyester (PET) were developed as carded needle-punched nonwovens. The acoustical absorption coefficients of these floor coverings, and of floor coverings in combination with an underpad (either a rebonded polyurethane foam, or a soft cotton nonwoven) were evaluated by ASTM E— 1050 in the frequency range of 100 to 3200 Hz. By stacking an underpad and a floor covering together, a floor covering system was created. The measurements demonstrated that each of the natural fiber-based nonwoven floor coverings contributed to noise reduction, e.g., coefficients = 0.54—0.81 at 3.2 kHz. Noise was significantly reduced with a floor covering system using either of the underpads. The most reduction occurred with a polyurethane pad; for example, for kenaf floor covering C20-1 the coefficients at 3.2 kHz were: 1.0 with polyurethane versus 0.81 with cotton pad.

Natural Plant Fiber Composites-Constituent Properties and Challenges in Numerical Modeling and Simulations

“…Sound in an object (e.g., a commercial passenger car) is generally propagated through the air (airborne sound), and by vibrations of the body (structural sound). In the science of acoustical control, two classes of acoustical treatments can be used to address airborne noise, namely barriers and absorbers while for structure-borne noise, isolators and dampers are two possible treatments [Parikh et al, 2006]. Natural fibers and their composites are potential sound absorbers and noise reducers.…”

Effect of Fiber Orientation on Mechanical Properties of Kenaf-Reinforced Polymer Composite

“…The use of kenaf fiber can provide lower density than the traditional materials and has resulted in lightweight and eco-friendly automotive interiors. Not only that, it has been shown that the cellulosic-based non-woven fiber has better sound absorption and noise level reduction (Parikh et al 2006). This sandwich layer composite is a very efficient structural design with the benefit of being lower in cost.…”

Improved Sound Absorption Performance of Nonwoven Fabric using Fabric Facing and Air Back Cavity

“…Kenaf, jute, waste cotton as well as flax are mixed with polypropylene and polyester. It is found that their sound insulation performance is good and relatively better than commercial cotton pad [5]. Tascan and Vaughn (2006) study the effect of total surface area and fabric density of a needle punch nonwoven fabric on the acoustical performance.…”