1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW16225 Acoustic Wheel House Liner Materials Copyright 2012 General Motors Company All Rights Reserved March 2012 Originating Department: North American Engineering Standards Page 1 of 14 1 Scope This standard describes the requirements for fi
2、ber-based acoustic wheel house liners attached to the exterior of the vehicle. 1.1 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 well. The material shall be a moldable, self-supporting com
3、posite 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 house applications. 1.1.1 Material and Performance Classification. Identification: The specific performance characteristics
4、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, flexural rigidity and hydrophobicity. 1.1.1.1 Weight per Unit Area. Type 1: 1000 10% gsm (gram per square meter) Type 2: 1200 10%
5、gsm Type 3: 1400 10% gsm 1.1.1.2 Acoustic Absorption Level. Wheel liner shall perform to the acoustic absorption level specified on engineering drawing, Level A, or B. See 3.2 and Table 3. If no level is specified on the drawing, the default shall be Level A. 1.1.1.3 Water Pass-Through Class. Class
6、1 No water pass-through allowed. Impermeable barrier required either locally or globally. Wheel liner must meet all requirements listed in Tables 1 and 2 and all Class 1 requirements where noted. The fabric and film lamination must be tested. Class 2 Minimal water pass-through permitted (full compre
7、ssion in a region). Wheel liner must meet all requirements listed in Tables 1 and 2 and all Class 2 requirements where noted. Class 3 - Some water pass-through permitted (regular compression in a region). Wheel liner must meet all requirements listed in Tables 1 and 2 and all Class 3 requirements wh
8、ere noted. If no class is specified on the drawing, the default shall be Class 3. 1.1.1.4 Flexural Rigidity. Rigidity of wheel liner shall be specified on engineering drawing, followed by the suffix “R-” (see section 8 Coding). 1.1.1.5 Hydrophobicity. Wheel liner hydrophobicity shall be called out o
9、n the drawing (H = hydrophobic, NH = non-hydrophobic). See Section 8 Coding for specifics. 1.2 Symbols. Not applicable. 1.3 Typical Applications. 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 ma
10、terial 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 wheel house area with standard mechanical fasteners such as push pins, threaded fasteners, et
11、c. 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 requireme
12、nts (stiffness, acoustics, water pass-through, geometry, etc.) 1.4 Remarks. Not applicable. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS
13、GMW16225 Copyright 2012 General Motors Company All Rights Reserved March 2012 Page 2 of 14 1.5 Limitations on Usage. The materials described in this specification are designed for use in applications where the component will not exceed temperatures of 120 C. Above this temperature, additional insula
14、tors or reflectors can be applied and need to be tested in vehicle. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO 178 ISO 9053 ISO 9073-18 SAE J913 ISO 2589 ISO 9073-17 ISO/IEC 17025 2.2 GM Standards/Specif
15、ications. GM9531P GMW3208 GMW14124 GMW14872 GMW3059 GMW3221 GMW14177 GMW15725 GMW3116 GMW3259 GMW14334 GMW3182 GMW3326 GMW14700 2.3 Additional References. TMC003 Material Safety Data Sheet guidance documents (available at ). 3 Requirements 3.1 General Requirements. 3.1.1 Test Data. Lab testing shall
16、 be performed by a laboratory that conforms (meets requirements but may not be formally recognized by a third party) to ISO/IEC 17025 and is acceptable to the responsible GM department. Test reports must conform to 5.10.2 and 5.10.3 of ISO/IEC 17025. Supplier shall submit a letter of compliance. 3.1
17、.2 Standard Conditions (GMW3221-A). All test specimens shall be conditioned to GMW3221 Code A for a minimum of 24 h, unless the test method indicates that standard conditioning is not required or that other conditions apply. 3.1.3 Material Construction Specification. All required information shall b
18、e reported on the Wheel Liner Carpet Construction Specification Data Form. See Appendix C, Data Form C1. A form shall be submitted along with each carpet material submitted for Engineering Approval. Established values for a construction will be reported on and controlled within the limits establishe
19、d on the Construction Specification Data Form. See Appendix A, Data Form A1. 3.1.4 Color Material Specification. All required information shall be reported on the Color Data Form. A form shall be submitted along with each textile material submitted for Engineering Approval. Established values for Co
20、lor Material data will be reported on and controlled within the limits established on the Color Specification Data Form. See Appendix B, Data Form B1. 3.2 Test Requirements. All testing shall be conducted on mass production representative materials. Flat panels shall be used for Table 1 testing. Thi
21、s material must be representative of mass production materials and process (weight, thickness, manufacturing process, etc.) Production parts must meet performance requirements as outlined in Table 2 per performance level as indicated on engineering drawings. Unless otherwise specified in the appropr
22、iate test procedures, at least three test pieces shall be tested. For test procedures that require a complete component, components shall be randomly selected from a minimum of 50 parts, if not otherwise agreed with responsible Materials Engineer. Copyright General Motors Company Provided by IHS und
23、er license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16225 Copyright 2012 General Motors Company All Rights Reserved March 2012 Page 3 of 14 Table 1: Material Requirements Note 1 Test Test Proce
24、dure Requirement Resistance to Mildew GMW3259 There shall be no visible growth or odor of mildew. Resistance to Fluids (Engine Compartment) GMW15725 (section 4.7: Resistance to Fluids. Test Fluids; A, D, F, G, H, I, K, M, N, P, Q) There shall be no color change, loss of bond, material degradation or
25、 tackiness following the test. Resistance to Fluids (Exterior) GMW14334-B Rating 3 Abrasion Resistance GMW3208 - 1000 cycles, H38 Wheel, 1000 g weight There shall be no holes, fuzziness, separation, or other changes that impact the function of the wheel house liner or reduce the perceived quality of
26、 the vehicle. Breaking Force ISO 9073-18. (Test both Machine Direction (MD) and Cross Machine Direction (CMD).) Shall be a minimum of 90 N/cm: As received. After gravelometer Exposure (GMW14700 Method B, five cycles of 473 mL approximately 700 g, gravel). Salt Staining Resistance GMW14872 There shal
27、l be no physical deterioration or permanent staining. Evaluate after Exposure A, Exterior cycle, 4 salt sprays per cycle, Method SH. Resistance to Water Wicking SAE J913. (Test MD and CMD) Report water wicking after using solution A for 16 h. There shall be 5 mm wicking. Tearing Resistance GMW3326.
28、(Test MD) and CMD) Shall be a minimum of 110 N: As received. After gravelometer Exposure (GMW14700 Method B, five cycles of 473 mL, approximately 700 g, gravel). Acoustic Permeability (not required for Class 1) ISO 9053. Test the specific airflow resistance of five (5) specimens each taken from nomi
29、nal thicknesses. Report average specific airflow resistance in liters per cubic meter per second on construction sheet. Pressure shall be 500 Pa and orifice size of 100 mm2. The fibrous wheel house liner performance is designed to comprehend the air gap on the B side of the liner. The fibrous wheel
30、house liner material shall have a flow resistivity (inverse of permeability) of 1500 500 mks rayls. Acoustic Performance (not required for Class 1) GMW14177 (400 Hz to 10 000 Hz) See Table 3. Freeze - Thaw Expose plaques to 14 cycles of GMW14124, Cycle K. (Test plaques in both a vertical and horizon
31、tal position.) The plaques shall exhibit no objectionable degradation after the test such as: wrinkling, distortion, delaminating, expansion, shrinkage or other distortion that will interfere with normal function. Copyright General Motors Company Provided by IHS under license with General Motors Com
32、panyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16225 Copyright 2012 General Motors Company All Rights Reserved March 2012 Page 4 of 14 Test Test Procedure Requirement Impact Resistance (Gravelometer) GMW14700, Method B Fiv
33、e cycles of 473 mL (approximately 700 g) gravel. Test in the following conditions: As received = after 16 h at 23 C, 50% relative humidity (RH) At low temperature = tested at -30 C At low temperature = tested at -30 C after soaking in water for 16 h There shall be no holes, fuzziness, separation, or
34、 other changes that impact the function of the wheel house liner or reduce the perceived quality of the vehicle. Flexural Rigidity ISO 178, 10 mm deflection, span set at 50.8 mm, sample size of 25.4 mm x 152.4 mm, crosshead speed of 12.7 mm/minute. (Test MD and CMD.) Shall be a minimum of 5 N. The w
35、heel house liner material shall be of sufficient rigidity to be self- supporting in application and resist deflection in use. Report average load. As received. After gravelometer Exposure (GMW14700 Method B, five cycles of 473 mL, approximately 700 g, gravel). Water Barrier Film Peel Strength (Class
36、 1 only) Perform peel at an angle of 180 on a power driven machine with a constant rate of 300 mm/minute jaw separation. Perform peel test: As received After each cycle of the Temperature Humidity cycle (Dimensional Stability) (total of 2 peel tests) Minimum peel strength of 525 Nm, or cohesive fail
37、ure of one or both of the fabric and film. Note 1: Test samples shall be 2.5 mm nominal thickness for Type 1 materials, 3 mm nominal thickness for Type 2 materials, 3.5 mm nominal thickness for Type 3 materials. Table 2: Part Performance Requirements Test Test Procedure Requirement Weight per Unit A
38、rea GMW3182 Report values. Typical values: 900 to 1500 g/m2, based on performance needs. Measurements should be made over the entire part. Thickness ISO 2589 Report values. Measurements should be made over the entire part. Freeze - Thaw Expose entire wheel liner assembly to 14 Cycles of GMW14124 Cyc
39、le K. Test an entire wheel house liner in “vehicle position” mounted in a rack, or fixture. (Test one part only.) The wheel house liner part shall exhibit no objectionable degradation after the test such as: wrinkling, distortion, delaminating, expansion shrinkage or other distortion that will inter
40、fere with normal function after. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16225 Copyright 2012 General Motors Company All Rights R
41、eserved March 2012 Page 5 of 14 Test Test Procedure Requirement Resistance of Material to Heat Aging Expose entire wheel liner assembly for 168 h at 85 C. Test an entire wheel house liner in “vehicle position” mounted in a rack, or fixture. (Test one part only.) The wheel house liner part shall exhi
42、bit no objectionable degradation after the test such as: wrinkling, distortion, delaminating, expansion shrinkage or other distortion that will interfere with normal function after. Resistance to Temperature Humidity Cycle (Dimensional Stability) This cycle shall be carried out two times without int
43、erruption: 17 h 0.5 h at -30 C 3 C. 72 h 1 h at +75 C 3 C. 24 h 1 h at +40 C 3 C and 93% 5% RH 7 h 0.5 h at -30 C 3 C. 24 h 1 h at +40 C 3 C and 93% 5% RH. 24 h 1 h at +22 C 3 C Test entire wheel house liner in “vehicle position” mounted in a rack, or fixture. The wheel house liner part shall exhibi
44、t no objectionable degradation after the test such as: wrinkling, distortion, delaminating, expansion shrinkage or other distortion that will interfere with normal function after. The parts must be checked on the checking fixture before and after the environmental cycle. Impact Resistance (Gravelome
45、ter) GMW14700 Method B Five cycles of 473 mL (approximately 700 g) gravel. Test in the following conditions: As received = after 16 h at 23 C, 50% RH At low temperature = tested at -30 C At low temperature = tested at -30 C after soaking in water for 16 h There shall be no holes, fuzziness, separati
46、on, or other changes that impact the function of the wheel house liner or reduce the perceived quality of the vehicle. High Pressure Cleaning Resistance GM9531P Method B The wheel house part shall be subjected to high pressure spraying with water on the tire side per GM9531P Method B with the follow
47、ing substitutions: Pressure: 8.27 MPa (1200 psi) Spray Impingement: 90 to Surface 25 Nozzle Fan 75 mm Nozzle to Surface 15 cm/s sweep 10 s duration for each sweep (sweep is forward and back) 520 sweeps The wheel house liner part shall exhibit no holes, fuzziness, separation or other distortion that
48、will interfere with normal function. Class 1 no water pass through. Class 2 and 3 measure height of water plume and report. Place a scale on the backside of the part perpendicular to the surface. Provide a short video showing the test setup and height of plume. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16225 Copyright 2012 General Motors Company All Rights Reserved March 2012 Page 6 of 14 Test Test Proce
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