[CARBON FIBER REINFORCED POLYAMIDE] 1 UNIVERSITI TEKNIKAL MALAYSIA MELAKA FACULTY OF MANUFACTURING ENGINEERING DEPARTMENT OF MATERIAL ENGINEERING ACADEMIC YEAR 2015/2016 SEMESTER 3BMFB BMFB 3293 COMPOSITE PROCESSING AND ENGINEERING Assingment 1 : Carbon Fiber Reinforced Polyamide 6,6 as Substitution for Metal Used in Car Seat (Automotive Application) by MUHAMMAD AL-ASYRAF BIN DIN (B051410074) Submitted to : Dr. Zaleha Submitted on : 25 APRIL 2016 1
2 [CARBON FIBER REINFORCED POLYAMIDE] 1.0 Introduction The car industry uses a tremendous number of materials to build cars, these including iron, aluminum, plastic steel, glass, rubber, petroleum products, copper, steel and others. These parts are used to create everything from those small things we don't think about, such as dashboard needles and wiring, to the big stuff, such as the engine block or the transmission gears. These materials have evolved greatly over the decades, becoming more sophisticated, better built, and safer. They've changed as new automotive manufacturing technologies have emerged over the years, and they're used in increasingly innovative ways. The automakers have a competitive market in building a better car. Like the chassis to the entire vehicle, the seat frame is the structure that supports the seat. It's basically the skeletal system where the main parts of the seat are attached. So naturally, when this structure breaks down, it need to immediately carry out the replacement to avoid any potential problems. The most popular ones material used in car seat frame is carbon steel. It rusts more easily when exposed to air and moisture, however, as the carbon content rises, steel has the ability to become harder and stronger through heat treating. The downside is that it becomes less ductile. The weight also higher, thus contribute to a higher overall weight of the car. This conventional car seat frame also require many manufacturing process, these components have to go through are stamping, metal-plating, bending, welding, and riveting. As for surface treatment, the specific metal used in creating the frames could either be galvanized, copper-plated, chrome-plated, electroplated and thus making the cost of production is higher. 2.0 Problem Statement Vehicle weight reduction is a well-known strategy for improving fuel consumption in vehicles, and presents an important opportunity to reduce fuel use in the transportation sector. By reducing the mass of the vehicle, the inertial forces that the engine has to overcome are less, and the power required to move the vehicle is thus lowered. In this study, weight reduction as a strategy to reduce fuel consumption will be explored, primarily on the vehicle level. The study focusing on the selection of what interior component in the car, which contributes higher weight distribution, is car seat, making it the top list part of component needs to be redesigned in term of material used. The suitable candidate for this application is Carbon Fiber Reinforced Polymer. 2
[CARBON FIBER REINFORCED POLYAMIDE] 3 3.0 Materials analysis Table 1: Compressive strength of a few selected reinforcing fiber Type of Fiber Tensile Strength (GPa) Compressive Strength (GPa) E-glass fiber 3.4 4.2 T-300 Carbon fiber 3.2 2.7-3.2 AS 4 Carbon fiber 3.6 2.7 P100 Carbon fiber 2.2 0.5 Table 2: Mechanical properties of selected material for car seat frame Properties Carbon fiber Metal E-Glass Type ( gcm-3) T1000 HT Carbon Steel Strength Gpa 7.06-3.4 Tensile Modulus gpa 294 190 72.4 Compressive Strength (GPA) 2.7 AS 4-4.2 Density g/cm3 1.8 7.85 2.54 Poisson ratio - 0.27-0.3 - Thermal conductivity (W/m.K) (In Epoxy) 5-7 in plane 0.5-0.8 in transverse 80 - Table 3: Typical properties of resin (at 23C) Properties Cast Epoxy Resin Polyetherimide (PEI) Polyamide-imide (PAI) Density (g/cm3) 1.2-1.3 1.27 1.4 Tensile Strength (MPa) 55-130 15.2 26.9 Tensile Modulus (GPa) 2.75-4.10 3.0 3.03 Table 4: Properties of commonly Used Polymer Resin Properties Thermoset matrices Thermoplastic matrices Epoxy Vinyl Ester Polyamide 6,6 PET Density (g/cm3) 1.3 1.2 1.14 1.35 Tensile Moduls (Gpa) 4.5 3.3 1.6-3.8 2.8-4.1 Tensile strength (Mpa) 130 75 95 48-72 Strain to failure (%) 2-6 4 15-80 30-300 CTE (10^-6 'C) 110 50 144 117 Maximum service temperature ('C) 90-200 100 110 120 3
4 [CARBON FIBER REINFORCED POLYAMIDE] * sources were taken at various books, see the appendices for more details. 4.0 Discussion Carbon fiber Carbon exists in various allotropic forms. The three important forms are graphite, diamond, and fullerenes. Carbon atoms are arranged in a hexagonal fashion in the graphite structure. It has layer structure with closely pack and strongly bonded carbon atoms in the layer and weak van der Waals forces between the layers. Graphite is a highly anisotropy material, because of this structure. This is the form that exists in carbon fibers. Diamond has a cubic structure with strong covalent bonding in all three directions. Carbon fibers are made from organic precursor fibers, which undergo large amount of plastic deformation before fracture. These fibers are converted to carbon fibers on pyrolysis. The widely used precursor fiber is polycrylonitrile (PAN) fiber (Morgan,2001) PAN Carbon fiber as reinforcement PAN Carbon fiber is the most common textile precursor, which it is the one type of the carbon fiber. The molecular structure of PAN are randomly arranged on either side of the chain. PAN carbon fiber are generally categorized into high tensile (HT), high modulus (HM), and ultrahigh modulus (UHM) types. It also has lower thermal conductivity than pitch carbon fibers (Minus, 2005) and microstructure of PANbased carbon fiber has relatively good layer arrangement and small stack heights, which minimize interlayer, shear failure and hence improve compressive strength. Advantage of Carbon Fiber Carbon fiber is Corrosion Resistant and Chemically Stable. In car mar maker industry, any material should resist with corrosion as to have a longer lifespan. Compare to carbon steel, the carbon fiber is higher corrosion resistant. Carbon fiber has good tensile strength Tensile strength for carbon fiber is 7.06 GPa which is X higher than old material (carbon steel), the value different shows that amount of maximum stress for the material can withstand while being stretched or pulled before necking or failing. This is important, as the car seat is the hot spot in car safety because it would give higher impact to the passenger when collide. Carbon fiber has high strength to weight ratio Even there is any other material would be a good candidate to substitute the metal used in car seat such E-Glass as a reinforcement (Table 2- strength and density) but the carbon fiber relatively has highest strength yet lowest weight compare to two others material in Table-2. Carbon fiver has a lower density In table 2, there is 6.05 g/cm3 difference between carbon fiber and carbon steel density which carbon fiber contribute lower weight. This weight reduction, approximately 70% reduce would give high impact to car s fuel consumption. 4
[CARBON FIBER REINFORCED POLYAMIDE] 5 Thermoplastic matrices Thermoplastic are inherently tough and resistant to damage from low velocity impacts. In addiction to impact resistance, thermoplastics have excellent abrasion resistance. They exhibit attractive dielectric properties and these properties are not significantly affected by moisture absorption (Mallick, 2008) Polyamide 6,6 as matrices Nylon 66 (aka nylon 6-6, nylon 6/6 or nylon 6,6) is a type of polyamide. Nylons come in many types, and the two most common for textile and plastics industries are nylon 6 and nylon 66. Nylon 66 is made of two monomers each containing 6 carbon atoms, hexamethylenediamine, and adipic acid, which give nylon 66 its name (Palmer, 2001). Advantage of Polyamide 6,6 as matrices Polyamide 6,6 has a lower density By referring the table 4 above, polyamide 6,6 is the lowest in weight compare to others. As mention earlier, weight reduction could improve fuel consumption and car performances. Polyamide 6,6 has higher strain to failure In general, it have higher strain to failure than thermoset polymer which may provide a better resistance to matrix micro cracking in the composite laminate.it is necessary for a seat to withstand load or elongated more before failure as it would give low stiffness to the car seat design. The Polyamide 6,6 has a higher strain to failure compare to epoxy and vinyl ester as in table-3. Polyamide 6,6 has higher impact strength The most important advantage of thermoplastic polymer over thermoset polymer is their high impact strength to strength and fracture resistance, which it turn impart an excellent damage tolerance characteristic to the composite material. Shorter fabrication time Epoxy has a long fabrication time in the mold (where the polymerization reaction, called the curing reaction to transform the liquid polymer to a solid polymer). As carmaker industry nowadays, has a larger mass volume production per year compare to aerospace industries, the time taken production per part need to be highly considered. 5.0 Conclusion Carbon fiber reinforced Polyamide 6,6 as material substitution from carbon steel used in car seat s frame. After undergo material selection and analysis to determine the substitution material for the metal used in car seat frame, some of the advantages are figured out The weight is reduced-the weight is reduced approximately 70% from the old material 5
6 [CARBON FIBER REINFORCED POLYAMIDE] Required lesser space- The foam required to cover the frame is lesser thus would give a larger room leg to the passenger Easy of handling-there is no slightly adhesive or gummy to the touch during the processing Can be recycled- Thermoplastics are easily recyclable, compared to thermosets, because the polymer chain does not degrade when melted down. Thus the mass production of the car will not going to waste after lifespan Reference 1. Morgan, P. (2001). Carbon Fibers and Their Composites. Taylor & Francis. 2. M.L Minus and S. Kumar, The processing, properties, and structure of carbon fiber, JOM, 57:52 (2005) 3. Mallick, P. K. (2008). Fiber-reinforced-composites (3rd ed.). CRC Press Taylor & Francis group. doi:978-0-8493-4205-9 4. Palmer, R. J. (2001). Polyamides, Plastics. Encyclopedia of Polymer Science and Technology. 3. 5. Li, Qingwen; Li, Yuan; Chikkannanavar, S. B.; Zhao, Y. H.; Dangelewicz, A. M.; Zheng, L. X.; Doorn, S. K.; et al. (2007). "Structure-Dependent Electrical Properties of Carbon Nanotube Fibers". Advanced Materials 19 (20): 3358 3363.doi:10.1002/adma.200602966. 6. Ratcliffe, E.H., National Physical Laboratory, Teddington, Middlesex, England, quoted by Weast, R.C. Editor-in-Chief, Handbook of Chemistry and Physics, 48th edition, 1967-1968, Cleveland: Chemical Rubber Publishing Co., page E6. Appendices 6