Bumper beams

As with SMC, appHcations are limited to high volume because of the capital investment in equipment and tooling. Thermoset compression molders require additional heating and material Handling equipment to adapt their process to thermoplastic sheet fabrication. AppHcations include automotive bumper beams, load floors, radiator supports, battery trays, and package shelves. Chair sheUs, military containers, material Handling pallets, trays, and concrete foaming pans are also produced. 

HTPC (Hybrid ThermoPlastic Composite) bumper beams made by Plastic Omnium are used by General Motors on the Pontiac Montana, Chevrolet Venture and Oldsmobile Silhouette. Continuous woven fibres are overmoulded with a long or short fibre reinforced polypropylene to save weight (6 kg), enhance impact resistance (20-40%) and integrate numerous functions such as reinforcement ribs. The process is fully automated. 

EPP foam inserts for bumpers (fenders) are a major application area (91) (98) (161) (279) (302) (362) (366) (386) (398) (424). Unlike EPS, EPP has the multiimpact performance required, can fit inside the hollow bumper beam, and has a low mass. ABAQUS FEA has been used (a.28) to design such inserts. Arange of cross-sectional shapes were considered in an attempt to achieve a near uniform crushing load of about 3 kN over a deflection of 50 mm. Those with triangular cut outs were found to be best. 

The combined use of continuous-glass-strand mat as a core material and uniformly and monoaxially aligned continuous-glass fiber as the surface material has also been proposed (5, 25). The incorporation of expanded polystyrene copolymers into composites was proposed for shock-absorbing composites, such as bumper beam cores, knee bolsters, etc. (17, 18). 

Typical applications in development with these PP/PS alloys include automotive bumper beams, pillars, sporting and recreational equipment, sledge hammer handles and other consumer tools appliance components. The lighter weight (lower... 

Polyamide/polycarbonate blends have been evaluated for exterior automotive applications such as bumper beams. Their dimensional stabil-... 

The front and rear bumper beams on the 1993 Toyota Corolla were made fiom polypiopylene/fibeiglass composite. Estimate the longitudinal modulus of these beams assuming a fiberglass (E-glass) composition of 50%. 

Xycon Amoco TPEs/TPU — Bumper beams, electr. 

A combination of chopped roving and preform may also be used. The use of PUR gives a wide range of properties, extending towards elastomeric (for parts such as automobile fenders or bumper beams) and introduces cellular/foam forms. 

In Europe, the 5 kg recyclable front bumper beam for the Mercedes S range is produced in series quantities in a special grade of polypropylene GMT. To withstand impact up to 4 km/h without damage to itself or the car chassis a Mercedes internal requirement, approximating to USA... 

Polypropylene nanocomposites are remarkable for their better mechanical properties, such as high tensile strength and modulus, and for their dimensional stability. They have a wide range of applications in the automotive sector [7-11]. The PP composites are used in automotive industry as battery supports, instmment panel carriers, body panel reinforcements, front-end modulus, underbody aerodynamic covers, electronic boxes, pedals and their supports, door panels and door modules, bumper beams, fender extensions, wheel covers, hub caps, and trim rings for wheels (Fig. 11.4). 

An excellent example of a compatible system is the 1997 Buick Park Avenue bumper/fascia system. The fascia is a TPO material and the energy absorber is PP foam snap fit to the aluminum bumper beam. Signal markers and trim strips are also snap-fit for easy removal. Therefore, a large amount of compatible material can be quickly removed from it for recycling. There has been a trend toward molded-in-color fascias on certain types of vehicles. These not only reduce mass but also eliminate the environmental burdens associated with painting. Molded-in-color fascias have been used on a variety of small cars and some sport utility vehicles. 

The joint venture between General Electric and PPG in 1986 to form the Azdel Corporation has created a unique composite market of its own. The most publicized application is for bumper beams (198). Azdel composite sheets were first introduced in the Corvette bumper system in 1984. Honda began to use it on the 1990 models (199). In 1992, the worldwide sales of glass mat thermoplastic was projected to be over 60,000 tons (200). Half of the sales were in the United States (32,700 tons). European sales, at 15,400 tons, were slightly more than that in Japan at 12,000 tons. In addition, Europe and especially Japan were projected to experience higher growth rate than the United States. 

HF Gdes. Effect of Processing Conditions on Thermoplastic Glass Reinforced Bumper Beam Performance. ANTEC, SPE, Toronto, 1997, pp 1976-1978. 

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