Acoustic Wheelhouse Liner Materials
|Publication Date:||1 January 2018|
Material Description. This material shall be comprised of a needle punched non-woven material that is molded and formed to the specific geometry of the wheel opening. The material shall be a moldable, selfsupporting composite with a uniform black color surface on the tire side of the parts and shall be suitable for use in exterior vehicle environments for protecting both front and rear wheel openings.
Material and Performance Classification. Identification: The specific performance characteristics required for individual parts shall be called out on the engineering drawings. These properties are: weight per unit area, acoustic absorption level, water pass-through, and flexural rigidity.
Weight per Unit Area: g/m2 (grams per square meter).
• 800 g/m2
• 900 g/m2
• 1000 g/m2
• 1100 g/m2
• 1200 g/m2
• 1300 g/m2
• 1400 g/m2
Note: Weights listed represent average area weight of finished part. Actual weight will vary depending on location of wheelhouse liner. This weight is for the finished part and not the blank.
Acoustic Absorption Level. Wheelhouse liner shall perform to the acoustic absorption level specified on engineering drawing, Level P (Premium, acoustical treatments per GMW14194 required), S (Standard) or M (Minimum). See 3.2 and Table 3. If no level is specified on the drawing, the default shall be Level S.
Water Pass-Through Class.
• Class 1: No water pass-through allowed. Impermeable barrier required either locally or globally. Wheelhouse liner must meet all requirements listed in Table 1, Table 2 and all Class 1 requirements where noted. The fabric and film lamination must be tested.
• Class 2: Minimal water pass-through permitted (full compression in a region). Wheelhouse liner must meet all requirements listed in Table 1 and Table 2 and all Class 2 requirements where noted.
• Class 3: Some water pass-through permitted (regular compression in a region). Wheelhouse liner must meet all requirements listed in Table 1 and Table 2 and all Class 3 requirements where noted.
If no class is specified on the drawing, the default shall be Class 3.
Symbols. Not applicable.
Applicability. This material is intended to protect the body and the engine compartment from water splash, road debris, and noise and vibration in the wheel area. The material acts as both a physical barrier and provides acoustic absorption, transmission loss, and internal damping related to impact noise. The material can be attached to body and frame components around the wheelhouse area with standard mechanical fasteners such as pushpins, threaded fasteners, etc. The material can also be welded to itself using sonic, vibration, or heat welding. Any welded areas should fail cohesively within the textile material and not exhibit clean separation.
The appropriate material type shall be selected for each vehicle application based upon the engineering requirements (stiffness, acoustics, water pass-through, geometry, etc.)
Remarks. This standard describes the requirements for fiber-based acoustic wheelhouse liners attached to the exterior of the vehicle.
Limitations on Usage. The materials described in this specification are designed for use in applications where the component continuous use temperature will not exceed 100 °C and the excursion temperature will not exceed 125 °C. Temperatures higher than 100 °C (continuous) or 125 °C (excursion) require additional insulators or reflectors to be applied and need to be tested in the vehicle.