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An innovative seat back design for fold down split-rear seat backs has been developed for application in SUV’s, MPV’s and hatchbacks. The all-thermoplastic seat back design meets US and European government regulations such as, the FMVSS 210, 207 in the US, and ECE 17 (luggage retention) in Europe. It is also expected to meet the newly introduced FMVSS 225 (child seat belt tether load) requirement. Currently application of the blow molded seat back is limited to sedans where the seat belt anchor loads are transmitted to a steel package shelf. For applications where the seat-belt anchor loads are transmitted to the seat back, hefty steel frame and reinforcements are required which add weight and cost to the seat back. The same is true for seats that need to comply with the European luggage retention requirement.

Contemporary interior designs make increasing use of soft feel and color harmony to provide a more luxurious and attractive environment for the driver and passengers. At the same time, progress in part manufacturing methods has increased the need for materials designed to work well in a variety of processes, such as injection molding, extrusion, blow molding, rotational molding and others. The focus of this paper will be on materials which are pre-colored to match OEM standards and are therefore capable of producing “ready-to-install” components without expensive post-operations like painting. The materials discussed will be in the 55–90 Shore A hardness range typically preferred by designers today, thereby avoiding the undesirable hard, “plastic” impression some other materials require as a trade-off. Plasticized PVC is often used in these applications for its good balance of performance and cost.

An exploratory study was performed to determine the feasibility of using oriented polypropylene rods as a replacement for metal in side impact beam applications. The study was divided into four phases: (i) laboratory testing of the impact and tensile properties of oriented polypropylene coupons, (ii) design of an oriented polypropylene side impact beam of comparable rigidity to that of a metal beam but with significant weight savings, (iii) development of a means of attaching the polymeric bar to the vehicle and (iv) flexural testing of a scaled down prototype. The oriented polymeric and metal beams exhibited comparable stress-strain behavior during scaled down testing. Although more research is required to validate the design of an oriented polymer side impact beam, the encouraging results suggest that oriented polymers should be considered for use in automotive components that can make use of their high specific strength and stiffness.

Usinor has developed organic and inorganic films, for many automotive applications. The surface post-treatments made by the coil-coater provide additional functions to the metallic coated steel, such as lubrication or corrosion protection, and offer an excellent compromise between car manufacturing, steel utilisation and costs saving. Even though the organic coating thickness can reach 8 μm, steel products can be welded and electro-painted, thanks to metallic pigments within the coating, which make the polymer conductive. In some particular cases, where high flexibility and formability are required, the best solution is organic non-pigmented systems with lower thickness from 1 to 2 μm. Other pre-painted steel systems with thicker organic coatings have the potential to replace ED-paint or to remove Primer-Surfacer on paint lines by the car manufacturer.

The desire to increase production and reduce cost while increasing environmental consciousness, is a constant challenge in the thermoplastic olefin (TPO) paint industry. Typically, TPO substrates are painted with an adhesion promoter for durability, and top coats for appearance. Although the adhesion promoter has an important function, the intrinsic value is not significant compared to top coats. A process and material was developed to eliminate conventional adhesion promoter spray application. By incorporating a novel adhesion promoter into the aqueous pretreatment system, many of the stresses of high production volumes, and operating costs were addressed while improving environmental awareness.

The paper describes a finite element procedure and material model that can be used to predict the post-impact geometry of a thermoplastic bumper energy absorber. The material used in the study is a thermoplastic PC/PBT blend. The methodology presented determines the final geometric shape based on a new finite element material model. The material model uses a secant return modulus that is a function of the plastic strain. The conversion of material data into a finite element material model, along with a finite element procedure for analyzing multiple impacts, is discussed. Comparisons of finite element predictions to test data are also presented.

A recent trend in the auto industry has been an increasing focus on the environment, which demands that product designs be “eco-friendly”. For this it is important to design products that can be easily disassembled or formed of combustible materials. Accordingly, forming parts using a single kind of recyclable material is the most effective way to satisfy the above-described requirement. We therefore took this approach with the development of an air cleaner filter. While a conventional air cleaner filter for an engine is generally composed of three parts, that is, filter medium, sealing material, and frame, we developed a recyclable air cleaner filter formed only of the filter medium. To do so, however, it was critical that both sealability and durability of the filter medium be maintained. In order to achieve this, a thermoplastic non-woven fabric was used to produce the filter.

Due to the wide and ever increasing application of thermoplastics for the transportation and automotive industries, the performance of the under-the-hood plastic parts depend upon optimized design and processing technology and properties of polymer based materials. Nylon (polyamide) based plastics are used widely for automotive cooling fans and various under-the-hood injection molded components. For injection molding of multi-blade cooling fans and various rotating plastic parts the complex of multiple gating injection molding tools were used. Both the design of the various rotating parts (including industrial and automotive cooling fan, and the molding tool design are very important to get optimum flow patterns and to predict the locations and interaction of stress-bearing areas and knit lines (planes or inter-phases)1. The mechanical performance of the injection-molded thermoplastic components depends on the peculiarity of the part and the molding tool design.

Engineering thermoplastics were successfully utilized in the design of injection molded rotating parts such as the impellers, wheels, and cooling fans of commercial air-cooled chillers, and gas and diesel engines. Complex aerodynamic and mechanical performance of impellers and cooling fans are very important for the efficiency of integrated air-movement, climate control and cooling systems of various types of engines of vehicles, cars, heavy-duty tractors and trucks. The transportation and automotive industries have developed a culture of reliability and cost effectiveness, in which high risks and adventures are not encouraged. Due to the wide and ever increasing application of thermoplastics for the transportation and automotive industries, the performance of the under-the-hood parts depend upon optimized design and processing technology and properties of polymer based materials.

Automobile manufacturers are currently searching for ways to eliminate the traditional painting process employed in assembly plants to decorate and protect the exterior of an automobile. The entire paint facility in a typical assembly plant runs anywhere from $200,000,000USD to $600,000,000USD and can occupy 50% or more of the factory floor. Add to this the cost of environmental compliance, energy, raw materials and labor and it’s easy to see why elimination of the paint operation can a huge benefit to car manufacturers. GE Plastics has recently developed a novel polymeric film that can eliminate the need to paint. The film is based on a new polymer invented recently at GE CR&D in Schenectady, NY. This polymeric film can be applied over a variety of thermoplastic and thermoset substrates through an In-mold decoration (IMD) process to yield Class A, pre-finished exterior panels and trim that can then be assembled without the need for painting.

The Valyi surface finishing/compression molding process (SFC) has successfully been used to produce large structural panels with Class A finishing films under low pressure using short glass/carbon fiber reinforced materials and engineering materials. The material used in the SFC process must meet certain performance requirements in order to fully exploit the capability of the process. This paper reports the mechanical properties and rheological properties of short and long glass and carbon fiber reinforced materials. The fiber distribution in the parts produced by SFC have been compared to that from conventional injection molding. The long fiber reinforced PP resins show enhanced stiffness and impact strength. The methods of improving appearance due to long fiber read through have been investigated in this paper.

A comparative study of the mechanical performance of welded polyamide joints is evaluated. Under optimized welding (linear and orbital vibration, hot plate, transmission laser) conditions, the tensile strength of welded polyamide/nylon (filled and fiber-reinforced) is close or slightly higher (up to 14%) than the tensile strength of the base polymer (non-filled polyamide). In this study, the influence of two important effects (local reinforcement and “memory”) on the mechanical performance of polyamide/nylon welds is analyzed and discussed. The results presented in this study will help plastic part designers, material developers and manufacturers, choose optimized welding conditions for polyamide/nylon parts in a wide range of industrial applications.

This paper will describe a novel method for quantifying the perceived scratch and mar susceptibility of polymer surfaces. For automotive applications the relevant parameter that determines customer satisfaction is the visual perception of scratch and mar. Visual perception of a discontinuity on a surface is based on the contrast between the damaged area and its surroundings. The observed contrast differences are a function of the way in which light is scattered from the damaged area, as well as the illumination and observation angles. We have developed an imaging system that uses two geometries to capture the major contrast elements differentiating a scratch from its surroundings. The data from the two geometries are processed to extract values for reflectivity of the sample surface as well as that of the damaged area under the two observation conditions.

Automotive exterior paint systems can significantly affect the impact performance of thermoplastic body panels. To utilize the benefits of predictive engineering as a tool to assist in the design and development of thermoplastic body panels, thermoplastic body panel materials have been characterized with typical automotive paint systems for use for finite element modeling and analysis. Paint systems used for exterior body panels can vary from rigid to more flexible, depending on the vehicle manufacturer's specifications. Likewise, thermoplastics for body panels vary in mechanical properties, primarily depending on the heat performance requirements of the application. To understand the effects of paint systems on impact performance of thermoplastic body panels, two different paint systems, representing “rigid” and “more flexible,” were evaluated on two body panel grades of thermoplastics with different mechanical properties.

Crash simulation models require dynamic material property data to produce realistic predictions. The models often have to simulate multi-layered components that can contain polymers, foams, and metals. This paper describes a pilot study on the dynamic tensile properties of energy absorbing foams. The first phase consisted of the development of tensile test procedures suitable for high rate testing of foams. The second phase involved dynamic tensile tests on foams at rates up to 3.0 m/s. A half-scale ASTM D1623 Type A cylindrical tensile dog-bone was used for the dynamic tests. The pilot study showed that dynamic tests on foam were possible. The dynamic ultimate tensile strength, failure strain, and stiffness of three foams at various rates were measured. The groundwork has been laid for the development of a foam tensile test standard for the automotive industry, with the potential of generating shared databases.

A biaxial test procedure is used to assess the constitutive properties of polymers in tension. The constitutive constants are derived for high strain rate applications such as those associated with crashworthiness studies. The test procedure is used in conjunction with a time- and strain-dependent quasi-linear viscoelastic constitutive law consisting of a Mooney-Rivlin formulation combined with Maxwell elements. The procedure is demonstrated by describing the stress vs. strain relationship of a rubber specimen subjected to a step-relaxation input. The constitutive equation is transformed from a nonlinear convolution integral to a set of first order differential equations. These equations, with the appropriate boundary conditions, are solved numerically to obtain transient stresses in two principal directions. Material constants for use in the explicit LS-Dyna non-linear finite element code are provided.

Experimental modal analysis (EMA) provides many parameters that are required in numerical modeling of dynamic and vibratory behavior of structures. This paper discusses EMA on an exhaust system of an off-road car. The exhaust structure is tested under three boundary conditions: free-free, supported with two elastomeric mounts, and mounted to the car. The free-free modal parameters are compared to finite element results. The two-mount tests are done with the mounts fixed to a rigid and heavy frame. The rigidity of the frame is verified experimentally. The on-car test is done with realistic boundary conditions, where the exhaust structure is fixed to the engine manifold as well as the two elastomeric mounts. The two-mount and the on-car tests result in highly complex mode shapes.

A general three-dimensional finite element model was built to simulate the tracking conditions inherent in automotive front-end accessory drives, specifically, serpentine V-ribbed belt drives. Commercial finite element code ABAQUS was used for the simulation. The analysis is based on a hyper-elastic material model for the belt, and includes the effect of the reinforced cords and fibers in the rubber compound. The model can be used to study different parameters of the belt drive system such as rib number, pulley misalignment, drive wrap angle and drive speed. Experiments were used to validate the finite element model. Belt misalignment force of two, four and six ribbed belts under different misalignment conditions was obtained from experiment and compared with the results from the finite element model. Good correlation between these results brings confidence to the finite element model. Finally, typical FEA simulation results for a six-ribbed belt are presented.

Some engineers in the U.S. are still hesitant to change from graphite cylinder head gaskets to MLS designs due to surface finish capabilities at engine plants and in the aftermarket. Sealing these various hardware surface finishes is accomplished via a rubber on the surface. The coating's ability to conform to various surface irregularities while withstanding high temperatures, long term coolant and oil exposure, and joint shearing forces is paramount to long term sealing. This paper will explore the sealing capabilities of a highly conformable flouro-polymer rubber coating developed specifically to seal rougher surface finishes.

Predictive life determination of elastomer compounds is becoming increasingly important due to shortened development time and reductions in cost. Currently to select rubber compounds the automotive industry uses different specifications. In the USA and in most European countries these specifications are based on ASTM D 2000, and in Japan the specifications are based on JIS-B 2402. These test methods are mostly related to single point measurement. Unfortunately, from decades of long experience, engineers know that the real life time of elastomeric parts cannot be derived from these currently used specifications and test methods. During investigation of the sealing mechanism performed by Chicago Rawhide for many years the basic rubber properties responsible for seal life have been established. Using both standard ASTM and new methods for measuring the change in rubber properties during oil immersion aging, correlation were established between the kinetics of such changes and seal life.