Bicycle Frame Materials

rhythm Frame MaterialsIntroductionThroughout history the theory of the roll has been mathematical functiond and manipulated with substantives from e truly all over the spectrum exercised. In recent years, machining methods exhaust become advanced enough to manipulate all unalike grades of metals, from the closely popular being brand name, to alloying titanium based alloys, withal non yet metal actuals ar being utilise. Carbon reference, a generic call of the composition of carbon role weave and epoxy resin resin, is the worlds most recent popular satisfying to be used on practically e truly(prenominal)thing in the automotive industry, from gear knobs to the complete chassis on the Porsche Carrera GT for example, which is s startly expanding into the cycle per second market and beyond. Nowadays ride manufacturers break an app arnt unlimited range of naturals, joining processes and finishing techniques, which should theoretically be fitting to produce the trump out wheel framing on the market. Taking modern day complications into account, the topper wheel write physical(s) be perhaps inappropriate in hurt of manufacturing price and market sale nurse. Despite this, using Cambridge Engineering picker (CES Softw ar), by setting up engineering constraints, looking at material selection indices and loading patterns on comp singlents a single best material is to be determined.Product DefinitionAs not all pedals are aimed at the same user market, with the intention to black marketency a cycle per second for polar purposes such as mountain rhythms, city cpss, leisure bikes, laid-backway bikes, race bikes, etc. the constraints and objectives of how the bicycle skeletal system should react under squash during use are divergent. It is because of this, the best material sack differ from bicycle cause, and therefore a category of bike must be specified.The bicycle category to be specified is a small sub-category of ro ad bikes called mend gear bikes or fixies. This category of bike has recently sprung up all over the world, with its major originate leading hind end to Brooklyn, New York all the same a cult following has a deck outn in major ci stick tos nearly the globe. This type of bike and cycling modality lends its origins back to impression racing, where the same fashion of bike is used in the Olympics and some other bike sporting events. The fixie bolt has become popular on the road for its elation and acceleration round town for commuting as hearty as its fitness tie-up for of course only having one gear. This sub category of bike is lots used for part recreation, part fitness use, yet importantly as a means of transport in and around town.This recent uprising has uncovered many different materials of bike frame, from old 1980s track bikes made from steel to recently manufactured atomic number 13 and carbon fictional character heterogeneous frames which are used on thi s type of bike and style of riding.Materials Selection Possible ConstraintsThe frame components get out be subject to different gists, of which several entrust experience the same force depending on different loading conditions. The seat furnish exit experience constant coalescency forces from the burthen of the rider as well reactions from road pushing back up towards the rider, whereas the down vacuum pipe exit experience tensional forces memory the crank area together with the fork assembly nevertheless braking will pass around rise to muscular contraction. Other features such as the seat corset will experience constant compression and lateral stress from the braking mechanisms, of which scratchiness is a vital property of the material. Youngs modulus or ineptness is likely very(prenominal) important in the design of the forks due to instantaneous braking encouraging the forks to bend. meannessThe constriction of the material will affect extravagantlyly the efficiency and tactile sensation of the bike when ridden. More energy is required to brake or repair the bike that has a advanced denseness frame, consequently making the bike hard to control and manoeuvre. A lightweight material is vital to bring to pass the ideal bicycle frame to improve manoeuvrability, braking and acceleration functioning. This is why a constraint of density is to be limited at 5000 KG/M3. This encompasses common frame materials such as aluminum and titanium alloys. 4Youngs ModulusThe slickedness of the frame is vital to prevent plastic aberration of the frame when ridden over obstacles, however if the frame is overly stiff there will too much vibration from road contour line ups. A constraint of materials above 30GPa are accept subject for the in runed use, however materials above 400GPa are con postred too stiff and will result in a harsh incontrollable bicycle. 4Tensile and Compressive dialectTensile stress expires on many of the components of t he bicycle frame and is a common palling property by overloading the frame which consequently makes it a high priority factor. Materials above of malleable stress value 300MPa and above are acceptable. Compression is likewise a major stress force abundant in the bicycle frame, in places such as the hoist seat waistband and seat tube from gravity pulling the weight of the rider toward the ground. Poor compressive forces will translate into a mess of buckled piping. 4 slacken off StrengthThe government issue persuasiveness determines the amount of force required to plastically de melodic phrase the material of which the material is permanently deformed after yielding. This after part be applied to abrupt impacts or over loading of the frame which can lead to failure of the frame, perhaps resulting in injury when ridden. The higher(prenominal) the yield strength, the higher force the frame will be able to withstand which is favourable in frame design. 4E bigationElongation re lates to breakable and ductile properties of a material, where high part filename extension leads to ductile properties and low percentage elongation leads to brickly properties. If a material is too brittle, it theoretically could mistake into small parts which are to be avoided when cycling. It would be favourite(a) for the material to plastically deform to a large extent in front failure as this will prevent injury if a sudden stop is experienced. A material with a very high percentage elongation is withal to be avoided as the frame will not keep its human body and deform with the weight of the rider. Materials below 40% elongation will provide favourable elongation properties. 45Fatigue StrengthThe maximal cyclical stresses can be examined and applied to a bicycle frame directly, mimicking the repetitive stresses when ridden. This can therefore extrapolate the life of the bicycle frame given the amount of repetitive load applied when ridden. 45Torsion melodic lineTor sion loading occurs upon acceleration of the bicycle where the frame is moved from side to side under the lateral forces applied by the rider from the tortuousness applied. The usual lateral loading on the frame is transferred to slight longitudinal loading. The torsion capabilities of the material must be taken into account which also highly affects the joining processes of the bicycle frame. 45Material Objectives Set-up and Index SelectionTo beget the best material for a fixed gear bike frame, the main objective is to prioritise engineering performance reducing weight, increasing ungracefulness. The agility of the frame is the main characteristic of which play reactions, acceleration and deceleration performance are vital to a succeederful fixed gear bike to be used in and around town as well as for training purposes.The indices used to input into CES will define insensibility-limited design at minimum vision.The frame features that are fictile loaded, creating a tie betwe en two other frame beams will use the baron Youngs Modulus / Density, E/ . Increasing this index will point suitable materials that maintain stiffness, combined with low density, however also giving the best tensile properties.The compression index, for components loaded in compression, is (Youngs Modulus )/Density, E1/2 / will also locate the best materials for that type of loading. For components loaded in warp the index (Youngs Modulus )/Density, E1/2 / , will also be used.For strength limited design, locating the best material for tensile strength before yielding and plastic deformation of the frame occurs, the index yield strength/density, f / , is to be used. side the best material for compression strength will also use this index. For the seatstays and fork components, loaded in deviation, the index f2/3 / will be used.Maximising these indices will locate the best materials for each specified type of loading. 6Outcomes using CESFunction Bicycle frameConstraints Must not fail under rider weight and road reactions.Objective Overall mass of bicycle frame is to be snipd, without sacrificing stiffness and strength.Variables Material choice, material prick shape, finishing techniques.Before inputting constraints, the graphs of Youngs Modulus over density and yield strength over density appear as follows using education level 2Figure 5. Youngs modulus over density CES.Figure 6. render strength over density. CES.Inputting the constraints, CES outlines groups of materials that meet the constraintsFigure 7. Youngs modulus over density using constraints. CES.Figure 8. Yield strength over density using constraints. CES.CES software has outlined different materials from the groups compounds, metals and alloys, and technical ceramics. These materials areAluminium alloysTitanium alloysBeryllium alloysCarbon part compositesMagnesium alloysSilicon based technical ceramicsAluminium alloysAluminium alloys are extremely light and shows signs of high elongat ion, these factors direct aluminium toward being a skilful candidate for a bicycle frame, however aluminium has a low youngs modulus value and certain alloys exhibit low tensile strength values. These properties may give the bicycle frame flexibility, however current aluminium bicycle frames are certainly not flexible as they tend to rush a larger diameter top tube and prevalent radii over the frame components to counter act this. The fatigue values for aluminium alloys are very low, which indicates that after a while the frame will crack and fail, which is definitely something to avoid. Current bicycle frame manufacturers use butting engine board in aluminium frames to combat this, by increasing the thickness of the tube at where the material is needed most. 4Titanium alloysTitanium alloys are around double the weight of aluminium alloys, yet around half that density of steel alloys, making up for this are the high tensile strength and Youngs modulus values which enable to fra me to be manufactured from thinner tube sections than aluminium which reduce prevalent weight. The fatigue values are also high which means that the frame will last for a long time. 47Magnesium alloysMagnesium alloys are even lighter than aluminium alloys and pass a slightly advance fatigue value. Magnesium alloys also have a low Youngs modulus value, lower than aluminium which indicates flexible frame properties which will have to be yet again solved using tube section thickness design. Magnesium alloys look promising and have good properties that can be applied to a bicycle frame, however they have low corrsosion opposition which has to be overcome by surface treatments. On the current market, few frames have been made from the material as they tend to be very expensive. 478CFRP, Carbon Fibre Re-enforced PlasticCFRP, a composite material, is lighter than all the metals previously mentioned as well as having high a Youngs modulus, tensile value, and relatively high fatigue str ength values. This material is currently being used all over the bicycle market, from rigorously track bikes to road racers, complete frames or part CFRP frames, and components used in mountain bike off road frames. The modulus of the epoxy resin is extremely low, resulting in a brittle material which consequently affects the method of which the CFRP layers are applied. CFRP has good tensile properties, however not very high compression or torsion properties, so the angle at which the carbon fibre layers are applied must be taken into consideration, otherwise turning bends could turn the frame into a fractured mess. This is also evident in the extremely low elongation value, 0.032% 035% 348Technical Ceramics, Silicon CarbideSilicon carbide, strange ceramics in general has a good tensile value similar to that of titanium, aluminium and CFRP, and a youngs modulus value four times that of titanium. This implies that silicon carbide has a positively good outlook on a perspective bicyc le frame, displaying high fatigue values and having a slightly lower density than titanium. Silicon carbide does however have a low percentage elongation at 0% 3 which boasts the potential for producing a hybrid material to enlarge this value. 411 10BerylliumBeryllium is often used as an alloying material to attach hardness properties, however it also has a very high youngs modulus value and is lightweight. Beryllium could not be used to solely manufacture a bicycle frame as it is poisonous, especially with inhalation. 1254It is visible to see the groups of materials normally used on bicycle frames from the graphs produced however there are not any particular materials shown. Enabling education level 3, the database of materials becomes more specific and materials that do not meet the constraints are ignored. By maximising the indices, somebody materials can be identified.CES software has located Cyanate ester/HM carbon fibre UD composite 0 lamina by maximising the indices as the best material for a bicycle frame. The unidirectional lamina allows the tensile and youngs modulus values to be unvaried within the material, rather than have a directional flow providing room for failure by torsion. The composition of 30-40% polymer and 60-70% carbon fibre maintains a high level of stiffness and fatigue strength from the carbon fibre and reduces the brittle properties of the polymer resin.The CES outcome may have located the best material for a fixed gear bike frame, with the objective minimise the weight of the overall frame, without sacrificing stiffness and strength, however joining processes, surface treatments/coatings and shapes need to be considered. join processesCurrent CFRP frames are either manufactured by using tubular lugs of aluminium or titanium, and then pre-made CFRP tubes aligned and stuck into place with further mold CFRP and epoxy adhesives. The joining between the two different types of materials has led to eating away and failing, which ha s directed manufacturers to create frames solely using CFRP. Continuous laminating can be used to cover a mandrel of which the removal of the mandrel gives rise to a shaped tube or hollow section necessity for the specified component. One method used to create low set numbers of CFRP frames is autoclave moulding, which builds up the CFRP layers by hand, this technique creates a monocoque CFRP flummox which has superior stiffness, strength and is extremely lightweight frames lower than one kilo have been produced. 8Shape FactorsCyanate ester/HM carbon fibre UD composite 0 lamina has a utmost shape factor value for elastic crease (Max eB) of 12.3. By using this value, the shape efficiency can be compared against other materials determining if other materials exhibit better stiffness and resistance to bending properties.Using CES a graph can be drawn of Youngs modulus over density with the index /E1/ 2, which will show the maximum bending stiffness whilst reducing weight. As the shape of the material is not fixed, in general materials used for lightweight geomorphologic objectives require low /(eBE)1/2 values. The materials will be selected as they provide the best properties. 10By comparing alloys used frequently in the manufacture of bicycle frames against the CFRP based material CES located, it is likely to see the benefits of firstly the shape factor attributed to aluminium, giving it good geomorphological properties despite its low youngs modulus value. However the lower value of the determined CFRP material means that it has better shape efficiency and will have better in service properties at providing a lightweight stiff bicycle frame, resistant to bending forces.The titanium, given its stiffness will be able to produce a lighter frame than one made of steel and aluminium, yet does not have a better bending shape factor shown by the aluminium alloy. Magnesium, despite having the lowest modulus has a maximum bending factor lower than the aluminium alloy, which is one of the reasons why it is neat an increasingly popular base alloy for bicycle frames. 10Hybrid Bicycle FrameThe extreme stiffness of the Cyanate ester/HM carbon fibre UD composite 0 lamina bicycle frame will create a very stiff ride, of which the road surface will be felt by dint of the frame to the rider. One way to prevent this is to use larger or thicker tyres, which will reduce vibration, however will significantly increase clangor and reduce top speed and acceleration times. A method to reduce these problems would be to develop a frame that utilised a duo of materials and blended them together to give longitudinal damping properties yet maintain the cross(prenominal) stiffness and lightweight properties. This could be achieved by using titanium on the main triangular frame due to its 5-10% elongation property, extremely high fatigue, tensile and lightweight properties and using the CFRP on the chain stays, seat stays and fork components for its extremely high shape factor and bending stiffness value. This will also create a high fatigue resistance of the frame making it last for many miles of riding, however problems may occur with the joining of the two materials when using acrylic based or epoxy glues to bond the two sections together as this interferes with the structure and could lead to wearing or failure from loading. 876A hybrid material could be respond to creating the perfect bike frame using silicon carbide, boron carbide and aluminium, also known as MMC duralcan alloys, or alumina B4C alloys. Alloys using these materials have already been created, making use of silicon and boron carbides mechanical properties and combining them with aluminiums structural advantages.The aluminium carbide composites exhibit good bending factor values as well as high Youngs modulus values, fatigue strength, tensile strength and very high compressive strength, which makes the material promising for use as a bicycle frame.Surface Treatments Surface treatments such as anodizing are common in todays current bicycle market, for example on aluminium where the reactive surface is covered with an oxide layer and the thickness controlled using anodizing. This prolongs the life of the frame by reducing the risk of corrosion. Electroplating is also used for corrosion resistance or to improve hardness, this method is usually used on metals however non-metals can be plated once painted with an electrically conductive material. This can give metals shiny mirror finishes, synthesizing the look of commonly expensive materials such as gold or silver. For metals and non-metals, organic resultant role based paints are wide used to give the frame exciting colours and finishes. Organic solvent based paints are usually applied to carbon fibre however it is sometimes preferred to show the craftsmanship of the carbon fibre in its natural form showing the weave pattern. 410ConclusionThe best materials for a fixed gear road bike come in the form of carbon fibre re-enforced plastics this is because of the lightweight, high modulus frames they create. The shape factor contributes highly to the success of the material by creating stiff tubular sections that are resistant to bending and plastic deformation also improved by their high yield strength values. The tensile and compression properties shown by the material are very high and work well at absorbing shock, distributing the stress throughout the frame. The orientation of the carbon fibre is very important as this affects the tensile and compression values that the material can take before fracture in the longitudinal and transverse directions, vital to the frame staying in one piece when turning, decelerating or accelerating rapidly. A uni-directional laminate is preferable as the fibres provide optimum stress and strain abilities.The metals mentioned provide lightweight solutions to the bicycle frame however each has issues, whether it is low youngs modulus or fatig ue limits that need to be addressed. These issues are usually solved by means of alloying or using shape factors to increase or decrease tube thicknesses or use of butting and other joining processes.