Search Results

Different solutions for trunk floors recently presented on the market have been collated and investigated in order to better define the possible features integrated and the acoustic performance of trunk load floors. A description protocol has been devised and applied to systematically categorize the whole set of features potentially characterizing a trunk floor, and the wide range of solutions used with respect to materials, processes and design configurations. The acoustic performance has been specifically addressed with the evaluation of the acoustic absorption on both sides and a specific testing procedure to evaluate the noise insulation capability provided by actual parts.

The environmental issues are mounting for a global automotive industry associated with ever-increasing output. Major issues include fuel consumption, vehicle emissions, consumption of non-renewable materials, and recycling of waste materials. This paper provides an overview of recent advances in new acoustic materials based on recycled and sustainable sources for “environmental” vehicle sound packages that address NVH and trim acoustics requirements. Thanks to new eco-design standards, both the OEM and suppliers can increase and improve eco-friendly aspects such as recycling end of life vehicles. The use of end of life materials in a new car includes: automotive shredded residue (ASR) such as tire fibers included in damping materials, chips foam from seats for acoustical shields, and automotive shredded residue for acoustical dash insulators.

For generations, fiber felt technologies have been used as a building block in the development of various absorbers and decoupler composites used for automotive acoustics. This development has led to a variety of felt components with increasing complexity in their differentiations. This paper will review the evolution of three generations of felt technologies. Generation 1 and 2 will discuss needled, resinated, and thermoplastic fibers bonded felts by comparing various performance indexes from physical parameters of raw materials, manufacturing processes, product applications and physical characterization along with acoustic properties. Generation 3 will introduce strategies, technologies, and approaches to further simplify the multitude of fiber felt innovations.

For several decades the majority of vehicle floor coverings have been designed around traditional carpet with an increased emphasis on covering the sheet metal with acoustic treatments. Current global vehicle design initiatives provide new challenges and these are directed towards the review of current product design in the light of vehicle life style concepts and vehicle life cycle requirements. At the same time practical solutions are needed to address global cost competitiveness. This paper gives a historic overview of automotive floor covering development from start to present and outlines current trends in new material and flooring concepts. It discusses technologies and product design approaches that are applicable to a more eco based carpet design and the covering of vehicle surfaces whilst meeting the global cost and practical key performance criteria for future vehicles.

Acoustical and Thermal treatments for automotive applications are constructed using a number of different materials and composites. These range from the simple needled felt absorber, to the sophisticated multi layer composites to provide noise and thermal Improvements. Since, in most cases a finish fabric or treatment typically covers these materials, the actual color of these substrates has not really been a key design criteria. This has allowed the Acoustics Integrators, when the function of the part is not compromised, to utilize recycled, and byproduct materials. These materials often provide superior performance, lighter weight, and reduced cost from the use of virgin materials. This model of Source Reduction for Acoustical and Thermal Product Design supports the environmentally sustainable Eco system. The End of Life directive may open up more recycled material streams by providing the necessary infrastructure to recover and process the automotive materials.

Acoustic packages are designed to excel in their primary function: sound reduction. Thereby, they already improve one environmental aspect, which is the reduction of the external noise emission. This paper explores the possibilities of increasing environmental value intrinsic to the product as well as the related potentials such as waste saving and the use of recycled materials. The discussion will also address the disposition of the acoustical parts when the vehicle is at the end of its useful life (ELV.) The critical issues within the recycling loops of acoustic packages as well as the potential of the recovered streams are highlighted.

The substrate selection for headliner composites is driven by acoustics, systems integration, weight and cost considerations. However, the acoustical contribution of headliners plays a primary role in their design. This paper highlights the acoustical contribution of the various headliner composites. Various current headliner composites based on glass-fiber mat, polyurethane foam, resinated reclaimed fiber composites are considered. New composite structures are developed that exhibit good acoustical performance. The random incident acoustic evaluation is performed in an alpha-cabin which serves as a small reverberation room.

Recycling of resinated and non-resinated reclaimed fiber pad, used in automotive applications as sound absorbers and insulators for headliners, package trays, floor insulators etc., has been ongoing for over thirty years. The feedstock for the fiber is a source reduction of textile industry waste, as compared to alternate first use material products. The fibers are actually reclaimed from apparel trim scrap (approx. 700MM pounds of apparel scrap produced annually). The acoustical trim product uses 60 to 100% of the available reclaim apparel scrap - material originally intended for basic necessities such as clothing, and in the case of resinated pad, blends this fibrous material with a binder resin (this only is a first use material.) During pad production, “pre-use” processing and trim scrap are reclaimed and re-introduced into production, up to 70% loading for resinated pad and up to 100% loading for non-resinated fiber pad.

The development of binder systems for automotive sound insulators as an alternative to phenolic resin is presented. Various thermoplastic binder systems were evaluated. The non-woven airlay process technology was used in manufacturing the padding. Subsequent cold thermoforming techniques were employed to produce molded sound insulators. Material characterization and part performance evaluation of mechanical properties, heat resistance, and acoustical performance were determined. Manufacturing process for the molded sound insulator was also demonstrated. The study concluded that a thermoplastic binder system, as an alternate to phenolic binder resin, can be used to produce functional molded fiber floor insulators.

Geometrical stiffening of the panels via rib design are considered due to vehicle design requirement and vibro-acoustic considerations. This paper studies the damping effectiveness of different damping treatments (extensional, shear damping structural damping layer - based on friction and inelastic collision) for flat panels and geometrically stiff panels. This paper considers the significant panel characteristics, damping efficiency of extensional and constraint layer dampers and structural damping layer. The overall vibro-acoustic reduction is measured over the low and medium frequency regions. The damping effectiveness on the panels is characterized by average vibration reduction, and frequency response function (FRF). The in-vehicle damping performance is measured experimentally with vibration excitation on in-vehicle size body panels.