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Many competitive headliner substrate materials were tested to determine the strengths and weaknesses of each material including new headliner materials such as those on the 97 Ford Expedition, 96 Chevrolet Cavalier, 97 GM G Van, 96 Ford Contour, and 96 Chrysler Cirrus, all of which are urethane/foam/glass layered substrates and the 96 Nissan Altima, a corrugated cardboard base substrate. In general, today's headliners are based upon three substrate types glass, foam, or cellulose (paper or cotton). Glass headliners are requested less frequently due to the lack of recycleability and the skin irritation caused to assembly plant workers. Of those substrate candidate materials screened, the best performing headliner substrate materials were 1997 Ford Expedition and 1997 GM G Van.

Recycling of automotive headliners has been carried out by grinding them and forming composites with isocyanate-based binders. Rear-seat-to-back-window trim panels have been prepared. Composites with 80-90 wt.% of scrap manufactured in plant runs exhibited mechanical properties comparable to the existing products. The rear-seat-to-back-window trim panel composites were produced by compression molding ground scrap-binder pre-preg sheets for 30 seconds at moderate temperatures, with no postcuring. This is the best indication that the utilization of the scrap headliners is both technically and economically sound. The plant runs have confirmed the feasibility of production of large parts with relatively complex shapes such as headliners. The adhesion of decorative materials to the composite substrates was excellent. More importantly, the decorative materials can be applied to the substrate during compression molding without any additional adhesive.

Layered structures made from elastic and porous materials are widely used as insulation systems in the automotive industry. They have a dynamic behavior which is strongly influenced by the various interaction mechanisms within the porous material. The paper concentrates on modeling such materials using a 3-D finite element (FE) approach. This model can be combined with a boundary element (BE) procedure in order to assess the radiated acoustic field. The key part of FE representation is a Biot's model for the two phase porous material. A mixed displacement formulation is selected. The model can be used for predicting the surface impedance and/or the acoustic transmission characteristics of layered materials. The combined use of this mixed FE/BE model enables also the evaluation of the acoustic response (radiated power, field pressure).

The effects of strain rate on the deformation behavior of steels were investigated to find the most appropriate micro structure of steel for anti-crash parts of automobiles, such as front-side-members. The dual phase steel absorbed a higher amount of energy during dynamic deformation than other steel with the same static yield strength. The increase of volumetric fraction of the austenite phase in the dual phase steel deteriorates the dynamic deformation behavior. The FEM analysis for crash test of member also showed the superior performance of the dual phase steel.

Headliner technology will be presented in this paper. Older established technologies such as cut & score, fiberglass, hardboard and resinated cotton are still used because of their proven reliability and low cost. But newer processes including polyester, natural fiber, Tramivex™ and urethane offer reliability, structure, acoustic performance and some recyclability. Fiberglass has always been a leader in acoustical performance but has breakage and handability issues in the assembly plants. This paper will be divided in four sections. The first section discusses manufacturing processes for headliners covering current and past. It also covers the materials used and types of facing. This section will state why headliner technology used in the USA is different than Europe or emerging markets. Second section describes acoustics. It will explain performance as related to material types. Porosity, cell type, fiber length and diameter is explained as it relates to the absorption of sound.

Several different steel sheets were tested for energy absorption, using hat square columns and dynamic crash testing. Results indicate that steel sheets containing large volume fraction of retained austenite have relatively high energy absorption. The relationship between retained austenite and energy absorption was analyzed. These special steel sheets have already been successfully used for production body parts, such a front-side-member, without difficulties arising in volume production.

This paper presents a new material technology that can achieve both crashworthiness and weight reduction of the vehicle body. This new technology is based on three fundamental approaches. One is a technique for evaluating high-speed material deformation characteristics related to the crush behavior of energy-absorbing structures. A second is the material concept of high tensile steel featuring both increased material strength and higher strain-rate sensitivity in order to improve its energy-absorbing capacity. We have found 590N/mm2-class dual-phase (DP) steel consistent with this concept. The third is a technique for estimating the crush behavior of body structures, taking into account the plate thickness reduction and work hardening distribution resulting from the press-forming process. Finally, it was shown that the use of DP steel results in a 15% reduction in the weight of absorbing structures without affecting crashworthiness.

Oil type, weight and storage time effects on formability of galvannealed sheet steels were examined in punch stretching (LDH) and friction (DBS) tests. The effects of oil weights between 1 and 8 g/m2 and storage times up to three months were examined. The results suggest that application of prelube or mill oil of about 3 g/m2 is desirable to maximize formability. Lower amounts of oil could lower punch stretchability somewhat from the maximum values. On the other hand, oil weights beyond 3 g/m2 did not appear to offer additional improvements in formability. DBS friction coefficients did not change with oil weight or storage time. Storage caused some variability in punch stretching test results for samples with the mill oil. The results indicate that prelube is beneficial for the formability of galvannealed sheet steels in the specific forming modes tested here, and the benefits continue after storage for up to three months.

The influence of coatings on fatigue behavior has been examined for the following commercially produced sheet steels: uncoated titanium stabilized interstitial-free (IF); electrogalvanized titanium stabilized IF; hot-dip galvanized aluminum killed, drawing quality (AKDQ); and galvannealed AKDQ. Fully reversed bending fatigue tests were conducted at ambient temperature on Krouse-type flexural fatigue machines. A dependence of crack development was observed and correlated to the microstructure and properties of the different coatings. Furthermore, a functional design relationship for each material was determined through stress-life analysis. The experimentally determined fatigue properties were compared to conventional estimates based on tensile properties which ignore coating effects. The results of this work suggest that ductile coatings may enhance fatigue resistance, while brittle coatings may reduce fatigue life.

There are a wide range of compounds that can be used as plasticizers, but esters of phthalic anhydride and saturated linear alcohols are particularly effective for flexible PVC used in soft automotive interior parts. Compared to esters derived from branched alcohols, esters derived from linear alcohols provide some unique advantages to the flexible PVC/ polyurethane composite to meet the high standards of automotive interior trim. The LINPLAST® plasticizers have proven plasticizer performance in flexible PVC formulations. The key to their excellent performance is in the linearity in the base alcohols used. These products are the highest molecular weight phthalate esters available with the highest degree of linearity. The main performance advantages of these plasticizers are their excellent fogging properties, UV degradation resistance, permanence, and short processing dry times.

Structural Reaction Injection Molding (SRIM) is generally regarded as a thoroughly developed technology and is currently utilized in many automotive applications; most prominently door panels but also other applications, for example package trays and headliners. The traditional production process involves the placement of a glass fiber mat into a mold prior to injection of a suitable liquid resin system. Upon removal of the part, the glass mat is thoroughly encapsulated by the resin system forming a structural composite material. In the new Long Fiber Injection (LFI) process, the glass fibers are injected along with the resin mixture onto the production mold. This new process demonstrates a new approach to high productivity, low cost manufacture of LD-SRIM composites.

The principles of an electronic nose are described briefly. It is shown how a sensor array in combination with pattern recognition software can be used for quality control and classification of car interior trim materials. Anomalies such as bad smelling leather and carpet are shown as outliers. The results are consistent with GC-MS TVOC measurements as well as with data from a human sensory panel. More needs to be done, however, regarding the sensor stability in particular before the sensor array can be used for routine classification of the trim materials.

Vibration welding has been acknowledged for decades as a viable, cost-effective alternative to the use of mechanical fasteners and adhesives in a range of automotive applications. These are primarily applications in which polymer parts are joined to like polymer parts to produce a weld which is more robust than that provided by other non-welding methods, such as hot melt adhesive. This technology and the equipment which supports it has enabled carmakers and Tier I suppliers to expand the use of state-of-the-art polymers into interior and exterior components which include those requiring a high level of structural integrity.

Lear Corporation has developed a new OneStep™ Liftgate trim module. The panel consists of all mechanical components and a trim cover assembled into one module. This structural liftgate uses the trim substrate and a “beam” as the common attachment point for all liftgate hardware. The assembly includes all of the liftgate components mounted to the back of the interior trim panel.

Successful simultaneous engineering requires a team with a high degree of engineering skill and experience, knowledge of the latest materials, processes, and methodologies; and it also requires finely honed people skills. Designing the workplace for people (DFP) can facilitate collaboration, increase quality and other significant metrics, and lead to an enhanced product greatly appreciated by the customer. Design for People applies the principles of performance technology to select and retain outstanding engineers, systematically train and educate for future competency needs, and reward and motivate through traditional and non-traditional approaches. Examples of best practice enable other organizations to apply the concepts of DFP.

This paper will summarise the results of a development programme to optimise the overall performance of AA6016 aluminium type body sheet product with special emphasis on hemming and surface texture. Hemming - The main problem associated with the hemming of aluminium sheet is crack formation on the hemmed radius. This programme has resulted in improved hemming properties: a flat hem joint is now possible in 1.2 mm AA6016 with 10% pre-strain. EBT-type of surface structure - EBT (Electron Beam Texture) surface structure consists of a regular pattern of isolated pockets in contrast with the well known random structure EDT (Electron Discharge Texture) and the highly directional structure MF (Mill-Finished). Compared with EDT and MF the EBT surface structure of aluminium gives improved forming behaviour and better paint appearance.

A study of an existing B-pillar was conducted to examine the changes required to increase the lateral load carrying capability by a factor of ten. A finite element optimization package was used to adjust the geometric and material characteristics simultaneously while minimizing weight. The results show that the weight and cost necessary for the ten-fold improvement in lateral load carrying capability were very low. Further, the results illustrate how structural design optimization with finite element modeling can be effectively utilized to create cost effective elements for use in an integrated occupant protection system.

A case study of the application of shape optimization technique to the design of the third cross-member of an automotive chassis has been presented. Its fundamental frequency is only marginally higher than the maximum operating frequency of the transmission and drive shaft, which are mounted on this cross-member. The objective is to raise the cross-member frequency as high as possible so that there is no resonance and resulting fatigue damage. A sizing optimization indicated that the mass was a predominant factor. Shape optimization using approximate direct linearization method was performed and a number of design directions were obtained. The fundamental frequency of the cross-member was raised by about 4 Hz.

Minor surface defects in the clearcoat film are common place realities in modern automotive painting operations. Finessing and polishing processes are required to remove these defects and restore the clearcoat to its original condition. Evaluation of new clearcoat technologies and polishing processes has always been very subjective. This drove the development of a standardized test method for evaluating the finessability of a clearcoat. In this paper the authors will compare and contrast the differences between the traditional method used to evaluate finessability with the newly developed standardized method. The standardized method shows distinct advantages when evaluating different clearcoat technologies and polishing processes.

This paper presents two new methods to quantitatively evaluate the mechanical durability of multi-layered automotive paint systems. The first examines the resistance of the paint system to particle impacts and involves the impact of hard particles against the painted surface, under controlled conditions. The second test examines the resistance of the clearcoat layer in the paint system to surface abrasion, or mar. The test uses a steel sphere which is rotated against the paint surface in the presence of a slurry of fine abrasive particles. These two techniques have been successfully applied to a set of commercial automobile paints, and were found to discriminate well between them and give reproducible, quantitative data. The effects of the bake conditions on both the erosion and abrasion resistance of a full paint system and the abrasion resistance of a range of commercial clearcoats are examined in detail.