COMPOSITE MATERIALS FOR OTHER APPLICATIONS We have given in Chapter 1 an idea on the diversity of the products which can be made using composite materials.'In this chapter we examine a few of these products,which form a good part in the evolution of these materials,excluding the aerospace sector presented in the previous chapter. 8.1 COMPOSITE MATERIALS AND THE MANUFACTURING OF AUTOMOBILES 8.1.1 Introduction Composite materials have been introduced progressively in automobiles,following polymer materials,a few of which have been used as matrices.It is interesting to examine the relative masses of different materials which are used in the construction of automobiles.This is shown in the graph in Figure 8.1.Even though the relative mass of polymer-based materials appears low,one needs to take into account that the specific mass of steel is about 4 times greater than that of polymers. This explains the higher percentage in terms of volume for the polymers.Among the polymers,the relative distribution can be shown as in Figure 8.2. The materials called "plastics"include those so-called "reinforced plastics"for composite pieces that do not have very high performance.The graph in Figure 8.3 gives an idea for the distribution by zone of the "plastic"pieces in an automobile and also shows the evolution in time.One can see the increasing importance of high-performance parts. 8.1.2 Evaluation and Evolution A few dates on the introduction of composite parts (fibers matrix)include: The antiques as shown in Figure 8.4 1968:wheel rims in glass/epoxy in automobile S.M.Citroen (FRA) 1970:shock absorber shield made of glass/polyester in automobile R5 Renault (FRA) TSee Section 1.3. 2003 by CRC Press LLC
8 COMPOSITE MATERIALS FOR OTHER APPLICATIONS We have given in Chapter 1 an idea on the diversity of the products which can be made using composite materials.1 In this chapter we examine a few of these products, which form a good part in the evolution of these materials, excluding the aerospace sector presented in the previous chapter. 8.1 COMPOSITE MATERIALS AND THE MANUFACTURING OF AUTOMOBILES 8.1.1 Introduction Composite materials have been introduced progressively in automobiles, following polymer materials, a few of which have been used as matrices. It is interesting to examine the relative masses of different materials which are used in the construction of automobiles. This is shown in the graph in Figure 8.1. Even though the relative mass of polymer-based materials appears low, one needs to take into account that the specific mass of steel is about 4 times greater than that of polymers. This explains the higher percentage in terms of volume for the polymers. Among the polymers, the relative distribution can be shown as in Figure 8.2. The materials called “plastics” include those so-called “reinforced plastics” for composite pieces that do not have very high performance. The graph in Figure 8.3 gives an idea for the distribution by zone of the “plastic” pieces in an automobile and also shows the evolution in time. One can see the increasing importance of high-performance parts. 8.1.2 Evaluation and Evolution A few dates on the introduction of composite parts (fibers + matrix) include: The antiques as shown in Figure 8.4 1968: wheel rims in glass/epoxy in automobile S.M.Citroen (FRA) 1970: shock absorber shield made of glass/polyester in automobile R5 Renault (FRA) 1 See Section 1.3. TX846_Frame_C08 Page 181 Monday, November 18, 2002 12:22 PM © 2003 by CRC Press LLC
mass distribution steel 75% polymers aluminum 16% textiles 9% #0.5% Figure 8.1 Use of Different Materials in Automobiles polymer mass distribution elastomers plastics (rubber) 45% 40% paints varnish in which tires:32% 15% Figure 8.2 Mass Distribution Among Polymer Materials Consequences of the introduction of composite pieces in automobiles are now well-known.They allow a number of advantages.One can find several common points with aeronautic construction.There are also disadvantages that are more specific to automobiles. ■Advantages include Lightening of the vehicles:A reduction of mass of 1 kg induces a final reduction of 1.5 kg,taking into account the consecutive lightening of the mechanical components. 2003 by CRC Press LLC
Consequences of the introduction of composite pieces in automobiles are now well-known. They allow a number of advantages. One can find several common points with aeronautic construction. There are also disadvantages that are more specific to automobiles. Advantages include Lightening of the vehicles: A reduction of mass of 1 kg induces a final reduction of 1.5 kg, taking into account the consecutive lightening of the mechanical components. Figure 8.1 Use of Different Materials in Automobiles Figure 8.2 Mass Distribution Among Polymer Materials TX846_Frame_C08 Page 182 Monday, November 18, 2002 12:22 PM © 2003 by CRC Press LLC
mass distribution mass distribution body elements body elements elements under the hood elements under the hood passenger compartment passenger compartment 49% 56.7% electricity electricity transmission transmission motor motor 23.5% 21.5% chassis chassis 20.7% suspension suspension 2.8% 2.7% 16.8% 0.5% 2% 2% 1.7% 1982:101.000tons 1987:181.000tons Figure 8.3 Distribution of "Plastic"Components in an Automobile 1955.Citroen DS 19(FRA) 1953,Chevrolet Corvette (USA). roof in glass/polyester complete body in glass/polyester 70.000 cars/year 10,000 cars/year Figure 8.4 Composite Pieces in Antique Cars Cost reduction:This is due to the reduction of the number of pieces required for a certain component and to noise reduction and isolation. The better corrosion resistance of the composite pieces. Significant disadvantages are It is difficult,for fabrication in large volume,to obtain as good a surface finish as that of painted sheet metals. For the car body,the painting process and the treatment of the surfaces require high temperature exposure. 2003 by CRC Press LLC
Cost reduction: This is due to the reduction of the number of pieces required for a certain component and to noise reduction and isolation. The better corrosion resistance of the composite pieces. Significant disadvantages are It is difficult, for fabrication in large volume, to obtain as good a surface finish as that of painted sheet metals. For the car body, the painting process and the treatment of the surfaces require high temperature exposure. Figure 8.3 Distribution of “Plastic” Components in an Automobile Figure 8.4 Composite Pieces in Antique Cars TX846_Frame_C08 Page 183 Monday, November 18, 2002 12:22 PM © 2003 by CRC Press LLC
How to Evaluate the Gains: In theory:These are the experimental vehicles;Ford,Peugeot (1979).As com- pared with the metallic pieces,composite parts have obtained mass reduction of 20%to 30%on the pieces for the body. 40%to 60%on the mechanical pieces Example:Ford vehicle,which has a mass in metallic construction of 617 kg and a mass in composite construction of 300 kg for a global gain of 52%.It is convenient to consider this case as "technological prowess"far from the priority of economic constraints. In practice:Over the past years,an increasing number of pieces made of glass fibers/organic matrices have been introduced.The following list contains pieces that are in actual service or in development. Components for the body ■Motor cap ■Hood cover ■Hatchback door ■Fenders ■Roofs ■Opening roof ■Doors ■Shock absorber ■Interior components ■Seat frames Side panel and central consoles ■Holders Components under the hood ■Headlight supports ■Oil tanks ■Direction columns Cover for cylinder heads Cover for distributor ■Transmission shafts Motor and gearbox parts Components for the structure ■Chassis parts ■Leaf springs ■Floor elements Figure 8.5 shows the importance of the volumes actually occupied by the composites in an automobile. Example:Automobile BX Citroen (FRA)1983 with a total mass of 885 kg. Many of the molded pieces made of glass/resin composites as shown in Figure 8.6 are now commonly used by the automobile manufacturers.We note in particular the two elements below,the importance and large volume production of which (rate of production of more than 1000 pieces per day),indicate a significant penetration of composites in the manufacturing of automobiles. 2003 by CRC Press LLC
How to Evaluate the Gains: In theory: These are the experimental vehicles; Ford, Peugeot (1979). As compared with the metallic pieces, composite parts have obtained mass reduction of 20% to 30% on the pieces for the body. 40% to 60% on the mechanical pieces Example: Ford vehicle, which has a mass in metallic construction of 617 kg and a mass in composite construction of 300 kg for a global gain of 52%. It is convenient to consider this case as “technological prowess” far from the priority of economic constraints. In practice: Over the past years, an increasing number of pieces made of glass fibers/organic matrices have been introduced. The following list contains pieces that are in actual service or in development. Components for the body Motor cap Hood cover Hatchback door Fenders Roofs Opening roof Doors Shock absorber Interior components Seat frames Side panel and central consoles Holders Components under the hood Headlight supports Oil tanks Direction columns Cover for cylinder heads Cover for distributor Transmission shafts Motor and gearbox parts Components for the structure Chassis parts Leaf springs Floor elements Figure 8.5 shows the importance of the volumes actually occupied by the composites in an automobile. Example: Automobile BX Citroen (FRA)1983 with a total mass of 885 kg. Many of the molded pieces made of glass/resin composites as shown in Figure 8.6 are now commonly used by the automobile manufacturers. We note in particular the two elements below, the importance and large volume production of which (rate of production of more than 1000 pieces per day), indicate a significant penetration of composites in the manufacturing of automobiles. TX846_Frame_C08 Page 184 Monday, November 18, 2002 12:22 PM © 2003 by CRC Press LLC
rear window doorframe opening roof side aileron roof support for window wiper rear light box hood gas hatch rear shield hub cab front rim shield front lower grill body reinforcing rear view front wheel lateral rib mirror upper piece protection door panel front fender roof opening roof frame demister upper lining ducts board back cylinder head plate cover battery spare tire support hatch and cover front face leaf spring headlight socket back shock structure absorber seat shell self supporting wheel motor shock fuel floor space support beam line Figure 8.5 Composite Pieces in an Automobile The hood is made of glass/polyester molded at high temperature in a press (20,000 kN)with the deposition of a gel coat during molding'to assure the quality of the surface.The following comparison is eloquent: 2 See Section 2.1.1. 2003 by CRC Press LLC
The hood is made of glass/polyester molded at high temperature in a press (20,000 kN) with the deposition of a gel coat during molding2 to assure the quality of the surface. The following comparison is eloquent: Figure 8.5 Composite Pieces in an Automobile 2 See Section 2.1.1. TX846_Frame_C08 Page 185 Monday, November 18, 2002 12:22 PM © 2003 by CRC Press LLC