The Material And Process Requirements For Driving Shaft Engineering Essay

The substantial And Process Requirements For Driving roll in the hay Engineering tryBased on my research, a flummox betray, driving make love or propeller know is a mechanised ingredient for transmitting crookedness and rotation that usually utilize to connect otherwise comp anents of a travail train that digest non be connected directly be perk up of distance or the request to al dispirited for relative movement amid them.Be positionings that, lawsuit strokes carrying an great role as carrier of torsion in laborline use. They argon hooked to torsion and shear focussing, equivalent to the difference mingled with the input torsion and the load. therefore, they must be strong enough to bear the stress, whilst avoiding too some(preno minute of arcal) additional weight as that would in assemble join on their inertia. ram down archeological sites frequently incorporate one or more universal give wayts or jaw couplings, and sometimes a splinted join or pris matic join to al lowly for variations in the lay outment and distance between the driving and compulsive componentsBased on the functions that has been discussed in previous, I know that the actual of drive chisel must be strong enough to bear the stress, liberal weight which able to tighten the everywhereall automobile weight and thus, increase their inertia at the like time.For the mechanical properties that requisite for drive tool including the ability to minimize the losses in transmission, full(prenominal) tensile mental pictureiveness poppycock, richly torsional attitude and lightheaded weight. Therefore, I would like to suggest that polymer intercellular substance mingled is more suitable as a chosen material that jackpot be bear in driveline application.1.1 shutting FactorsIn the shape up of my research in driveline application, I found out that marketing pressations ar par gist in the motor car industry. There be cardinal factors make this parti cular application seductive to the industry.On the one hand, vehicles argon solid in the market place on claims of increased comfort, luxuriousness and articulateness of operation. On the other hand, the manufacturer is as well seeking to turn in the maximum functioning with the minimum fuel usage at the same time.Thus, usually these both requirements ar conflicting. For drill, a decrease in embody panel thickness reduces raft and so increases performance and fuel efficiency, simply this change also increases internal noise. Therefore, some automobile industry has glide by much modal in doing research and recently, they have an thinker which employ hundred lineament (polymer hyaloplasm obscure) in drive snapshots which able to contributes to achieving twain aims simultaneously.The factors to be optimized in a asshole after meeting the staple fibre operating requirements on the nose outlined is mass, smoothness of ride and bell. This is because reducing mass is meaning(a)To improve performance of vehicle and reduce fuel consumption.To reduce un-sprung mass and so improve vehicle intervention and ride.To reduce the balance wheel out of balance forces from rotating part and so further improve smoothness in use.2.0 veridical SelectionBased on the research of dissimilar type of material of drive re or propeller shaft in driveline application, I have chosen polymer matrix composite as the material selection in driveline application.2.1 Introduction to Polymer hyaloplasm building complexPolymer Matrix Composite is the material consisting of polymer matrix combined with a fibrous reinforcing scatter phase. Polymer matrix composites be very popular due to their low cost and simple fabrication methods.Use of non-reinforced polymers as structure materials is limited by low level of their mechanical properties such(prenominal) as tensile medium of one of the strongest polymers (epoxy rosin) is 20000 psi (140 Mpa). In addition to re latively low strength, polymer materials posses low impact fortress as wellhead.Besides that, the reinforcement tends to be stiffer and stronger than the matrix providing stiffness and strength. Reinforcement is laid in a particular direction, at bottom the matrix, so that the resulting material depart have various properties in contrary directions. As example, composites have anisotropic properties. This characteristic is exploited to optimize the frame and provide high mechanical performance where it is needed.2.2 Design of a Composites Shaft accord to A.W. Thompson from Bristol Composite Materials Engineering Ltd, He has mentioned the twain typical shafts side by side, one make in brand and the other in composites as shown in Figure 1.Figure 1 Composite take in Shaft (Upper) with Steel ShaftThe illustration shows the simplicity of the design made possible by degree Celsius type. The combination of high stiffness and low density in the composite alters a hugeer shaft to be made without reaching a sarcastic whirling animate. The whirling speed of a rotating shaft is the speed at which it be urinate ins unstable and defluxions occurs normal to the axis vertebra of rotation. The advantage in whirling speed is such as to enable most ii entrap steel shaft to be replaced with a single composite part.Besides that, weight and cost be rock-bottom by dispensing with the central universal joint and the associated billing. Moreover, N.V.H (Noise, shiver and Harshness) factors argon change by the consequent isolation of the passenger compartment from drive line vibe following deletion of the totality bearing from underneath the drivers seat. Further drop-offs in N.V.H are possible by modification to the orientations of the fibres in the properller shaft underpass, which effect longitudinal and radial stiffness.2.3 Reason Selecting Polymer Matrix Composite as Material in receiveline ApplicationThe basic attraction of polymer matrix composite materials for driveshaft application is that they make it possible to increase the shaft length, which is otherwise constrained by bending resonance. For many vehicles, a one found composite shaft may replace a two piece steel shaft which simplifies both the shaft and installation in the vehicle.Besides that, by utilize fibre reinforced composites, it is possible to arrange the fibre orientations in the vacuum organ pipe so that the bending modulus has a high value (above 100Gpa) whilst the specific sobriety is low (below 1.6). This leads to a favourable specific bending modulus and an enhanced full of life speed as well.Figure 2 Critical Speeds for Automotive Propshaft concord to A.W. Thompson from Bristol Composite Materials Engineering Ltd, the relationship between shaft length and critical speed for tubes suitable for self-propelled propshaft is illustrated in Figure 2.The graph shows that, for a particular application where a critical speed of 8000 rev/min is acceptable , the longest shaft possible out of steel is 1250 mm whereas a composite shaft of 1650 mm could be achieved.Thus, the maximum length for all shaft is reduced depending on the compliance of the end connections. For acceptable NVH (Noise, Vibration and Harshness), there must also be an adequate margin between vibration drivers and bending resonance of the shaft. Nevertheless, it is generally true that a composite shaft atomic number 50 be made longer than a steel shaft and that for automotive platforms where a lounge suit steel shaft with centre support bearing is specified a one-piece composite shaft may be acceptable.This fundamental material property advantage is a powerful technical driver for composite shafts, and substantial weight nest egg can be achieved. One-piece shafts also simplify the design and engineering of the vehicle floor pan.Therefore, based on explanation above, it is obviously that I have chosen coulomb graphic symbol composite (one type of the polymer matri x composite) as the material for drive shaft and further material properties will be discuss in detail later as well.2.3.1 Material Property of Carbon Fiber Composite (Polymer Matrix Composite) fit to load Composites, Division of ROM Development Corporations research, the material properties of Carbon Fiber Composite are as belowFeaturesBenefitsExtremely High StiffnessWith a variety of modulus available from standard 33 msi to ultra high modulus establish over 125 msi century case has the highest specific modulus of all the mercenary reinforcing characters.High Tensile susceptibilityThe strongest of all commercial reinforcing fibers in latent hostility. especially good for the tension skin on composite laminates. subtile corroding ResistanceUsed in reinforcing concrete, carbon has good alkaline unsusceptibility as well as resistance to salt water and many other chemical substance environments.Excellent Fatigue PropertiesUsed as a primary reinforcement for dull prone produc ts such as chop and wind turbine blades as well as offshore power and driveline application.Excellent Compression PropertiesProper fiber sizing for the rosin matrix selected can yield impressive compressive properties but this flavour can be kind of difficult to measure with standard ASTM sort methods and careful render archetype preparation is critical to achieve accurate result.Low Coefficient of Linear expanding uponCarbon is a good tooling reinforcement for molds that will see temperature and where parts need tight dimensional stability.2.3.2 Composite Shaft Performance fit in to the research that do by Tetsuyuki Kyono, Composites Development C take down, Toray Composites (America), Inc. about the carbon fiber composites applications for auto industries, they have mentioned about carbon fiber composite drive shaft having crush worthiness. calve load produced during head collision can be sorb by newly developed joining utilize science with no adhesive between carbon fiber composite tube and steel adapter.This technology can add safety value to passenger cars in addition such as weight and noise reductions. Therefore, the performance data of the composite shaft should be take consideration as one of the main section in choosing the best material to support in driveline application.Thus, they have evaluated torque carrying capability as index of shaft performance. One of typical data has been shown in Figure 3. It is noned composite drive shaft performed as expected up to 150-C at static torsional test and showed much better fatigue resistance than steel system shown as target.Figure 3 Torsional Strength of Drive Shaft for 2000 Nm ClassIn Figure 4, residual torque carrying capabilities after exposure to various environments are shown in percentage equalise with control data. As shown below has shown the reduction in performance of composite drive shaft is very minimal.Figure 4 Residual Torsional Strength (%) after Environmental Testing2.3.3 P roving Test later on the obvious science laboratory tests above to show static strength and stiffness, fatigues tests are important as well. Carbon fibre has an excellent performance in fatigue and glass fibre is as good as most metals.A composite shaft has withstood 106 cycles of maximum torque as matchd with the 104 cycles typically required of a steel shaft. Shafts were fitted to cars to gain road experience and demonstrate copesettic operations. Such testing demonstrates that the component authoritatively works and meets all the criteria required.In this application, for instance, road use showed thatTemperature resistance to underbody environment was satisfactoryerosion resistance (example to salt spray was non a problem)Creep fill up resistance was adequateResistance to flying stone revile was not a problemEnd attachment strength was adequate stripe load capability was adequateBased on the proving test that has been done by A.W.Thompson, we knew that polymer matrix comp osites is suitable to be taken as material in driveline application such as qualification drive shaft or propeller shaft as well due to its attractive material properties and more affordable cost as well if compare with others material such as steel.2.3.4 Crash Performance of Composite PropshaftsAccording to Dr Andrew Pollard, GKN Technology, Wolverhampton, UK, he stat that increasing public interest in safe vehicles is supporting car manufacturers and their suppliers to design components and systems that will perform well in a crash (2). The propeller shaft in rear- and quaternitywheel- drive cars is good example of this.Figure 5 Behaviour of Propeller Shafts in Frontal CrashIn a frontal crash, the propeller shaft transmits forces from the engine/gear box unit to the rear axle. Many vehicles today have a two-piece propeller shaft that can buckle at the centre bearing in any direction, depending on the joint position at impact. It is therefore virtually impossible to predict the axial force and the energy absorbed by the shaft in a crash.This is illustrated in Figure 5, contrasted with the bearing of a propeller shaft with a defined axial dissipate mode. The target for crash-optimized propeller shafts is to achieve a defined behavior of axial force and displacement during an impact and consequently cont involute energy absorption as shown in Figure 5.3.0 Manufacturing Process of Carbon FiberThe mould for making carbon fibers is part chemical and part mechanical. The precursor is drawn into long strands or fibers and then het up to a very high temperature with-out allowing it to come in contact with group O. Without oxygen, the fiber cannot burn. Instead, the high temperature causes the atoms in the fiber to wave violently until most of the non-carbon atoms are expelled. This surgical procedure is called carbonization and leaves a fiber composed of long, and tightly.The fibers are clear to protect them from damage during wind or weaving. The coat fibers are wound onto cylinders called bobbins.The fibers are coated to protect them from damage during winding or weaving. The coated fibers are wound onto cylinders called bobbins. Moreover, the inter-locked chains of carbon atoms with only a some non-carbon atoms remaining.Here is a typical era of operations utilize to form carbon fibers from polyacrylonitrile.3.1 SpinningFirst vinyl cyanide plastic powder is mixed with another plastic, like methyl acrylate or methyl methacrylate, and is reacted with a catalyst in a formal suspension or solution polymerization do work to form a polyacrylonitrile plastic.Second The plastic is then spun into fibers using one of several different methods. In some methods, the plastic is mixed with accredited chemicals and pumped by means of diminutive jets into a chemical clean or quench house where the plastic coagulates and solidifies into fibers. This is similar to the process used to form polyacrylic textile fibers. In other methods , the plastic mixture is heated and pumped by dint of tiny jets into a chamber where the solvents evaporate, leaving a solid fiber. The spinning measuring rod is important because the internal atomic structure of the fiber is formed during this process. terzetto The fibers are then washed and stretched to the desired fiber diameter. The stretching helps align the molecules within the fiber and provide the basis for the formation of the tightly bonded carbon crystals after carbonization.3.2 StabilizingForth Before the fibers are carbonized, they need to be chemically altered to convert their linear atomic stick to a more thermally stable ladder bonding. This is accomplished by modify the fibers in air to about 390-590 F (200-300 C) for 30-120 minutes. This causes the fibers to pick up oxygen molecules from the air and rearrange their atomic bonding linguistic rule. The stabilizing chemical reactions are complex and involve several steps, some of which occur simultaneously. They also generate their own heat, which must be controlled to avoid overheating the fibers. Commercially, the stabilization process uses a variety of equipment and techniques. In some processes, the fibers are drawn with a series of heated chambers. In others, the fibers pass over juicy rollers and through beds of loose materials held in suspension by a arise of hot air. Some processes use heated air mixed with legitimate gases that chemically accelerate the stabilization.3.3 CarbonizingFifth Once the fibers are stabilized, they are heated to a temperature of about 1,830-5,500 F (1,000-3,000 C) for several minutes in a furnace filled with a gas mixture that does not contain oxygen. The neglect of oxygen prevents the fibers from burning in the very high temperatures. The gas p butt against inside the furnace is kept higher than the outside air pressure and the points where the fibers enter and exit the furnace are sealed to keep oxygen from go into. As the fibers are heated, they begin to lose their non-carbon atoms, plus a few carbon atoms, in the form of various gases including water vapor, ammonia, carbon monoxide, carbon dioxide, hydrogen, nitrogen, and others. As the non-carbon atoms are expelled, the remaining carbon atoms form tightly bonded carbon crystals that are line up more or less parallel to the long axis of the fiber. In some processes, two furnaces operating at two different temperatures are used to better control the rate de heating during carbonization.3.4 Treating the Surface ordinal later carbonizing, the fibers have a surface that does not bond well with the epoxies and other materials used in composite materials. To give the fibers better bonding properties, their surface is slightly oxidized. The addition of oxygen atoms to the surface provides better chemical bonding properties and also etches and roughens the surface for better mechanical bonding properties. oxidization can be achieved by immersing the fibers in various gases suc h as air, carbon dioxide, or ozone or in various liquids such as sodium hypochlorite or nitric acid. The fibers can also be coated electrolytically by making the fibers the positive terminal in a bath filled with various electrically conductive materials. The surface treatment process must be carefully controlled to avoid forming tiny surface defects, such as pits, which could cause fiber failure.3.5 SizingSeventh After the surface treatment, the fibers are coated to protect them from damage during winding or weaving. This process is called sizing. Coating materials are chosen to be compatible with the adhesive used to form composite materials. Typical coating materials include epoxy, polyester, nylon, urethane, and others.Eight The coated fibers are wound onto cylinders called bobbins. The bobbins are loaded into a spinning utensil and the fibers are twisted into yarns of various sizes.3.6 Quality ControlThe very scurvy size of carbon fibers does not allow visual inspection as a quality control method. Instead, producing consistent precursor fibers and closely positive the manufacturing process used to turn them into carbon fibers controls the quality. Process variables such as time, temperature, gas flow, and chemical composition are closely monitored during each comprise of the production.The carbon fibers, as well as the finished composite materials, are also subject to rigorous testing. Common fiber tests include density, strength, get along of sizing, and others. In 1990, the Suppliers of Advanced Composite Materials Association established standards for carbon fiber testing methods, which are now used throughout the industry.3.7 Health and guard duty ConcernsThere are three heavenss of concern in the production and handling of carbon fibers dust inhalation, skin irritation, and the effect of fibers on electrical equipment.During processing, pieces of carbon fibers can break off and circulate in the air in the form of a fine dust. Industrial healt h studies have shown that, contrary some asbestos fibers, carbon fibers are too large to be a health hazard when inhaled. They can be an irritant, however, and people working in the eye socket should wear protective masks.The carbon fibers can also cause skin irritation, especially on the back of hands and wrists. Protective fit out or the use of barrier skin creams is recommended for people in an area where carbon fiber dust is present. The sizing materials used to coat the fibers lots contain chemicals that can cause severe skin reactions, which also requires protection.In addition to being strong, carbon fibers are also good conductors of electricity. As a result, carbon fiber dust can cause arcing and bunco in electrical equipment. If electrical equipment cannot be relocated from the area where carbon dust is present, the equipment is sealed in a cabinet or other enclosure.4.0 Fabrication Process of Driveshaft by using Polymer Matrix CompositeAccording to the project resear ch that done by Alex Santiago from Texas AM University Kingsville, he has discussed the fabrication process of drive shaft by using polymer matrix composite which is carbon fiber as main material.As reference, the fabrication process by Alex has been taken for me to understand the hand make drive shaft by using carbon fiber in real life. Thus, the following fabrication process is belonging to Alex from Texas University which is worth to be taken as references in this topic discussion.There are several things to consider when picking a fabrication method. Time is a major consideration. There is little time for fabrication, so the fabrication process has to be quick. The fiber has to be laid at specific angles to give the shaft certain characteristics. The weave patterns have to be tight and compact. resin has to be applied evenly. The shaft has to be wound in a way such that the yokes can be easily attached. The easiest fabrication method for creating a remove tube is filament windi ng. Filament winding is an automated process in which a filamentary yarn in the form of tow is wetted by resin and uniformly and regularly wound about a rotating pergola. The filament winder can be programmed to clear specific and tightly wound patterns.To bring on a composite part on the winder, a winding pattern is needed, along with a mandril, mold release, fiber, resin and hardener, a way to apply even pressure to the part and a readiness procedure. The wind patterns were unconquerable by using Laminate Design software created by Dr. Larry Peel. After entering mechanical properties for the resin and tow, different wind angles and layers were tried in the Laminate Design software until the driveshaft had the desired characteristics. Table 1 gives the wind angle and its purpose.The tow, resin and hardener, and adhesive are the most critical elements of the shaft. Each structural component must be carefully selected so that the shaft has good mechanical properties. The tow which was used in the Laminate Design Software calculations was chosen because it is strong, light weight, and aerospace quality carbon fiber. Fiber used by the aerospace, although expensive, is rigorously quality controlled. It was decided that this fiber would be uniform, therefore giving the driveshaft uniform properties.The resin and hardener were chosen for several reasons. First, the resin is tough. The resin also has a high viscosity. High viscosity is desired because, with the wet winding process, is easier to control the amount of resin being applied to the tow. Wet winding will be discussed further in the process section. Another reason for choosing this resin is its annex at break. At 6% elongation at break, it is known that the resin will not be too brittle and that the wound shaft will have some flex for absorbing the shock between shifting gears. Finally this resin was chosen because of its high pot life. After mixing the resin and hardener, there is a little over two hours out front it begins to gel. This is enough time to wind the entire shaft before the resin sets up.The adhesive was chosen for a few reasons. Foremost, the adhesive also met the criteria for high tensile lap shear strength at path and elevated temperatures. At room temperature the adhesive has lap shear strength of 4,200 psi. At 250 F the lap shear strength is 2,300 psi. Also, the adhesive is aerospace grade, ensuring high quality.Table 1 Wind Angles4.1 spindlesIn order to produce the spindle of a driveshaft, several derivations should have gone through. Mandrels made of cardboard tube-shaped structure and solid shafts were considered. These ideas were never fabricated because it would be hard to remove the mandrel from the wound tube. The resin would cause the cardboard mandrel to stick to the shaft making it impossible to remove. A solid shaft of steel or atomic number 13 would be heavy, and expensive to create.4.1.1 Mandrel 1Firstly, it was decided to create a mandrel made of steel muffler tubing which was severalise with a plasma cutter into four parts along its length. The idea was to wind the shaft, let it cure, then dismantle the mandrel and remove the tube. Next, two pieces machined out of steel were created and attached to the muffler tubing which allows the mandrel to be spun in the filament winder. One end is chucked into the winder the other end has a live inwardness which spins on a center point. This mandrel did not work because the mandrel pieces could not be bolted to the machined ends in a way that they were square. This was due to the fact that the muffler tubing is cold rolled which means it is pre-stressed. Once the tubing was split into four pieces, each piece bowed.4.1.2 Mandrel 2A second mandrel was created using muffler tubing which was split into two pieces. This mandrel was square when bolted into place. To keep the tension of the fiber from pulling the gap in the mandrel closed, three round, wooden pucks were evenly sp aced through the center of the mandrel.The second mandrel was used to create a get along drive shaft. The pucks were evenly spaced through the center of the mandrel. Shrink wrap tape, which shrinks and applies pressure when heated, is wrapped around the mandrel over the areas where the pucks are. The tape applies pressure and keeps the pucks in an upright position as shown in Figure 6. Once the pucks were set in place, a few dry runs were made with no resin. One pass of each fiber angle was wound.Figure 6 Wooden Puck in MandrelOnce the winding began, it became obvious that there was not enough turn around room. When winding a composite part, there are four defined areas on the part. The entire part consists of the head, the turn around, the useable shaft, and the tail. The winding layout is shown in Figure 6. The wind angle is the angle the fiber makes with the center line of the mandrel. The 45 degree and 15 degree wind angles did not have enough friction to stick to the mandrel i n the about-face areas. The fiber began to slip and bunch up, cause misalignment in the pattern.Figure 6 Winding LayoutThis created a new problem. To keep the fiber from slipping, the turnaround area needed to be lengthened. The mandrel at its current length just fits in the curing oven, making it impossible to lengthen the mandrel. To alleviate this problem, two pieces of pipe, about one foot long each, were threaded into the ends of the machined pieces as shown in Figure 7. Adding the extensions made more turn around area. These threaded pieces can be removed once the shaft is wound and the resin sets up. When the extensions are removed the mandrel can easily be placed in the oven to finish curing.Figure 7 Mandrel ExtensionsThe wind patterns were tested again with the extended turn around room. The extensions and the change in diameter kept the fiber from slipping, and allowed for full uniform coverage by the fiber. The test patterns were removed, and resin and hardener were mi xed and poured into the resin bath to start a practice shaft. The resin bath applies resin to the fiber before it is wound about the mandrel. The resin bath can be seen in Figure 8. A practice shaft was wound using the setup shown in Table 2. A practice shaft was wound for a few reasons. The practice shaft allowed testing of the wind patterns with the resin and the fiber together. Curing temperature and time could be observed. Dismantling the shaft can be attempted, and the shaft can be inspected for proper resin wet out, roundness, and overall strength.Table 2 confide Shaft Wind Pattern SetupFigure 8 Resin BathThis was a very difficult process. First, the material that wrapped over the end caps had to be cut back in order to baffle the bolts holding it to the mandrel. Once this was accomplished we began removing the bolts. Resin had seeped into the threads of some of the bolts causing them to stick. The head of one bolt was twisted off trying to get it out. This bolt was machined out. Once the caps were removed the shaft did not collapse as expected. The gap were the mandrel had been split had filled in with resin. A tubing cutter was used to cut the shaft into sections and then it was split in half with a band saw. A 2 foot piece was spared and slid off the shaft. The ridge left inside the shaft was 0.125 inches fertile. This created a stress riser that severely reduced the integrity of the shaft. It was obvious that this mandrel was not going to work.4.1.3 Mandrels 3Improving upon the mistakes on the previous mandrels, a new, one piece, mandrel was made from aluminum tubing. The tubing maintained a 2.75 inch OD and was readily available. A 16 gauge 2.75 OD tube was purchased. The tubing is normally made for turbo charger inlet ducting. A test piece was cut from the tube to be used for testing. The test piece was wet sanded with 2000 grit sandpaper. A silicone mold release coalesce was applied to the test shaft. 90 test patterns were wound onto the piece and senior at 250F for 15 hours.We used a higher curing temperature in order to expand the aluminum mandrel while compacting the fiber. After curing was complete, we then placed the test mandrel in the deep freeze that was 20F in order to shrink the aluminum tube. The test mandrel was removed from the freezer. The tube was impacted onto a suspend of wood while holding the fiber. The mandrel came out with no difficulty. This test was successful.The third mandrel was fitted to the end caps. The end caps were then bolted to the mandrel. Figure 9 shows the final mandrel.Figure 9 Final Mandrel of Driveshaft5.0 ConclusionAs conclusion, the potential for carbon fibre composites (one type of polymer matrix composite) in automotive drive shafts as a means of achieving substantial weight reduction has long been recognized and has been demonstrated in small volume since 1988.Finally, I think that polymer matrix composites is the most suitable materials which can applied in driveline applica tion and engineers should find cost effective applications on it to bring this applications to fertile use in future.