Life Cycle Analysis Of Bicycle Engineering Essay

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Consider the statistics of 2007, all over the world the 137 million bicycles were produced which more than the double of the number of the cars produced in the world in 2007. Till 1980's the production of the car and bicycle were almost the same but there after from 1990's there has been steep rise in the production of bicycles. (Mathew, 2008) The bicycle promotion is mainly taking place because it is more efficient and cleaner alternative to the personal automobiles and can help cities in a way to reduce traffic, to solve the problems of smog and the pollution problems. Many of the government organizations and social groups in most of the countries are working to bring the cycles as a major part of the urban transport. (Mathew, 2008)

Figure 1: World Automobile and Bicycle Production from 1950 - 2008

Source: (Mathew, 2008)

There are tremendously increasing programs and policies all over the world for a considerable increase in the use of bicycles. The concerns over the increasing prices of the oil and the changing climate conditions would encourage people to go for cycling. The main motive the current study is thus focused on the analysis of a Bicycle. The Manufacturing process, the raw materials required, their impacts on the environment would be studied and presented. A comparative study on the various bicycle materials would be carried out and the best materials for the bicycle would be presented. The study would also involve a study related to the EC directives for manufacturing and the compliance of the bicycle manufacturing with the EC directives.

1.2 Aim

To carry out life cycle analysis for Bicycle: Comparative study of different materials and the Manufacturing Process

1.3 Objectives

To investigate the different materials used for bicycle and to carry out a comparative study of various materials with respect CO2 emissions

Study and Analysis using CES to find the right materials for Bicycle

To analyze the manufacturing process of bicycle and to investigate the direct impact of EC directives on the manufacturing process.

To analyze the disposal process and to investigate the direct impact of EC directives on the disposal process.

1.4 Methodology

Project Overview

Reviewing Objective

Understanding important concepts of Product Life cycle

Investigating Different Materials used for Bicycle

Studying EC directives for Manufacturing and Disposal

Investigate the manufacturing process and its compliance with EC directive.

Drawing out conclusions from the study and suggesting recommendations

Analysis of the Comparison

Investigate the Disposal process and its compliance with EC directive.

Comparative study of different materials with respect CO2 emissions

CES analysis to find the right material for Bicycle

Figure 2: Flow Chart for the Research

1.5 Expected Outcome and Recommendation

A thorough analysis of the different materials used for bicycle and a comparative study to find out the best materials in order to make bicycle more environmental friendly. Analysis of the manufacturing process would be carried and it would studied with respect to EC directives for manufacturing and would be checked to what extent they are being followed. On the basis of this suggestions and recommendations would be made on how the manufacturing process can be modified.



2.1 History of Bicycle

Leonardo Da Vinci envisioned a machine very similar to the modern world bicyle in 1940. But he did not go for developing the vehicle and even his sketches were not found till 1960s. The first attempt was made by Comte, a Frenchman, in 1700s when he invented the Celerifree which was a wooden hobby horse made with the help of the two wheels which are then joined by the beam. The person who will ride it will sit on the beam top and would propel by pushing the feet against the ground. The modified version came in 1816, when German man Baron Karl developed a hobby horse which was steerable. (Herlihy 2004) Few years after the development of this the riding of hobby horse became a fashion in Europe. The riders started experiencing and discovering newer methods and ways of riding. In 1840, Kirkpatrick Macmillan developed a two wheeled object which was operated with the help of treadle. He traveled around 225 km round trip to Glasgow with that and set a world record. A few years after that Ernest Michaux, developed a hobby horse which used rotating pedals and cranks connected to the axle in the front. (Herlihy 2004)

The main era of improvements in the bicycle started in 1860 when the metal-spoked wheels, ball-bearing hubs, a lever-operated gearshift with four speeds and solid rubber tires etc got invented. James Stanley in 1866 created a very unique Velocipede version. It had very large front wheel and the wheel at the back was small. It soon became very famous and got started to be exported to US. (Herlihy 2004)

In 1885, John Kemp, developed Rover Safety, the name safety was give because it was much safer than the Ordinary developed by the James. The safety developed by John had two equal size wheels made up of solid rubber, a diamond-shaped frame and a chain-driven rear wheel. The use of the Dunlop's pneumatic tires also took place in 1800s only. In 1898 the coaster brakes got developed and thereafter the biking became easier as the freewheeling would allow the continuous spin of the wheel without actually pedaling every time. (Herlihy 2004)

Figure 3: Bicycle Frame (Herlihy 2004)

2.2 Raw Materials

The main part of the Bicycle is its diamond shaped frame which is required for linking all the components of the bicycle together and in a proper configuration. The frame helps in providing rigidity and strength to the bicycle and the handling of the bicycle is largely dependent on it. In a frame there are rear and front triangle. The front in true sense forms a quadrilateral of four tubes: seat, the down, the top and the head tubes. In the rear triangle is the seatstays, chainstays and the dropouts of rear wheel. The steering tube and the fork are attached at the front of the frame to the head tube. (Caunter 1972)

For a lot of time in the history the main material for the manufacturing of the frame was steel or the alloy steel, very heavy but very strong. There had been continuous improvements in the frame material to increase the rigidity, durability, toughness, lightness, and strength. In 1970 a newer form the alloyed steels was developed which can now be welded mechanically resulting into the availability of inexpensive and lighter frames. In the recent years the light weight frames made of aluminum have become more popular. However the strongest metals are titanium and steels having large life spans as compared to that of aluminum which get failed due to fatigue within four to five years. (Caunter 1972)

In 1990s even lighter frames have been introduced with the developments of composite materials made of structural fibers like carbon.

The other components, than the frame, like brakes, wheels, chains and derailleurs are generally made of stainless steel.

Figure 4: Details of Bicycle Parts (Herlihy 2004)

2.3 Manufacturing Process

First of the seamless tubes which are required for constructing the frame are made from the solid steel blocks which are first pierced and then drawn into the tubes through various stages. The seamless tubes are generally more superior then the seamed tubes which are made with the flat steel strip stock by drawing it and then wrapping it in to the tube and then welding it along the whole length of the tube. Later buttering can be done or the tube wall thickness can be altered in order to manipulate the seamless tubes in order to increase their strength and to make them light. (Van Der Plas, 2005) Butting of joints and ends of tubes involves increasing their wall thickness as there most of the stress is applied, and thinning the walls at locations where there is little stress as in center of tube. The resilience of frame can also be increased by butted tubes. There can be different types of butting for a tube, single butted with one end made thicker, double butted with both ends made thicker as compared to the center, triple butted with either ends having different thickness, and quad butted which is resembles triple butted apart from the thinning of center towards the middle. However for certain bikes even constant thickness tubes are used. Welding by machine or hand-brazing is used for assembling the tubes, the later being more expensive process as it is very labor intensive. Plastic binders or strong glue may be used for joining the composites. Machines are generally used to manufacture the components although they may be attached by either hand or machine. Skilled bicycle builders make the final adjustments to the bike (Van Der Plas, 2005)

Assembling the Frame

Tailoring of the tubes- Annealing or softening of the metal is carried out by heating and then "hollows" or "blooms" are formed by hollowing them out. The heating of these blooms is carried out again, and acid is used for pickling in order to remove the scale and then they are lubricated. The appropriate dimensions are achieved by measuring the hollows and cutting them with precision. The adult bicycles have frame sizes ranging from 19-25 inch as measured from the top of the seat post to middle of the crank hanger. Then the hollows are put over a mandrel which is connected to a draw bench. Then a process called cold drawing is carried out on the hollows by passing them through dies stretching them into thinner and longer tubes in order to achieve right gauge. A variety of designs or lengths may be obtained by tapering and shaping the tubes. More then a dozen of operations may have to be carried out by taper-gauge fork blades in order to achieve the correct strength, resilience and weight. (Van Der Plas, 2005)

Brazing, Welding and Gluing - Hand or machine can be used to join tubes to the frame. Lugs which are metal sleeves joining various tubes at a joint may be used for joining the frames by welding, brazing or even simple gluing. Brazing is a special form of welding process the only difference being it is carried out at a lower temperature of around 871 degree celsius. A white flux is formed by using gas burners which are arranged evenly sound the lugs that are heated and this flux melts and cleans the surface, thus preparing it for brazing. The filler material that is used for brazing may be brass or silver that has a lower melting temperature than the material of the tubes being joined. The filler material seals the joint on which it is applied as it slowly melts around it. (Van Der Plas, 2005)

Aligning and Cleaning - After assembling the alignment of the frames is checked by placing them into jigs. As the frame is still hot and malleable various adjustments that are required can be made easily. Pickling with acid solution is carried out for removing the excess flux and brazing metals and this is followed by washing and grinding of the brazing until it becomes smooth. Further precision alignments if required are made after the metal has cooled down. (Van Der Plas, 2005)

Finishing- Then the painting of the frames is carried out which serves the dual purpose of giving a more finished appearance and also protecting the frame. A undercoat is used for priming the frame and the a colored enamel is used for painting the frame. Automatic electrostatic spraying rooms or hand-spraying method may be used for painting the frames. The positively charged paint spray is attracted by the negatively charged frames that are rotating for the full coverage. After this lacquers and transfers are applied on the frame. On some components like fork blades chrome-plating may be used instead of paint. (Van Der Plas, 2005)

Assembling the Components

Derailleurs and Gear Shift Levers - The gear shift levers may be mounted on various locations like down tube (used in racing bikes), on the handle bar ends or on the stem depending on the style of the bicycle. The rear and the front derailleurs are attached by a cable extending between them. Brazing or clamping of the front derailleurs (which are used for moving the chain from one drive sprocket to another) is done on the seat tube. However rear ones may be mounted on integral hangers or bolt-on hangers. (Van Der Plas, 2005)

Handlebars, Stems and Headsets- There could be various shapes of handle bars like raised, I dropped or flat. A bicycle stem which fits in to the head tube is used for bolting these stems onto them. The various headset components like bearings, locknuts and cups are attached to the head tube. The steering is made easier as the headset allows the turning of the fork inside the head tube. (Van Der Plas, 2005)

Brakes- Handlebars are used for mounting of the brakes. Cables are extended to the brackets and are also fastened to the calipers. A plastic or cloth tape can be extended to the handle bars followed by plugging of the ends.

Saddles and Seat posts- Generally steel or some aluminum alloy is used for making seat posts and they are bolted into position. A molded padding is used for making the saddle and then is is covered with plastic materials or nylon. In past leather was commonly used for saddles however it is seldom in use now.

Cranksets- It is used for proving a support of the pedals and for transfer of power to the chain and rear wheel from the pedal. They consist of crank rings, crank arms and a bracket assemble at the bottom which consist of axle cups and bearings and these are made of steel and aluminum alloy. Bolts and caps are used to attach them to the bottom bracket of the cycle frame. The ends of the crank arms have pedals screwed onto them. (Van Der Plas, 2005)

Wheels, tires and hubs- A J International Standards Organization (ISO) system for tires sizes and wheel diameters are conformed by the wheel manufacturers. Machines which roll steel strips into hoops which are further welded into rims are used for manufacturing the wheels. In order to accept the spokes the rims are drilled and these spokes are laced one round at a time between the rim and hub flange. In order to achieve uniform tension a wheel must be straightened in radial and lateral directions. After this the tire, rim liner and inner tubes are attached. Fitting of the chain onto the bicycle follows next. A free wheel which consists of several cogs and spacers is fitted onto the rear wheel and this free wheel helps to free the rear wheel from the crank mechanism when the rider stops pedaling. An axle running through the hub of the wheel is used to attach the wheels to the bicycle. Quick release skewers or bolts may be used to tighten the axle. (Van Der Plas, 2005)

2.4 European Union Directives for Bicycle

The standards for the Bicycle manufacturing, safety and liability where a little poor in Europe till 2006. But with the introduction of CEN standards and directives in 2006 for Bicycle manufacturing process, the safety requirements, the testing processes the beginning for making the bicycle as the more reliable and a cleaner mode of transport has started. In 2006, 4 European Union standards were introduced which are as below: (European Standards, 2006)

EN 14764 Trekking and City Bicycles

EN 14765 Bicycles for children

EN 14766 Bicycles for Mountains

EN 14781 Bicycles for road racing

The directives contains standards related to the manufacturing, safety requirements and methods of testing for the major components and parts of bicycle which includes frame, fork, seat, brake systems, gear systems, handlebar etc. (European Standards, 2006) Some of the European Directives are presented below. A detailed study of all the directives would be carried out in the further study.

Manufacturing Directives for Brake - Lever

The maximum value of the dimension d, which measured between the handlebar and the outer surface of brake lever which is in contact with the fingers of the rider should not be less than 40 mm. (European Standards, 2006)

Some exact values are as below:

For a bicycle with a height of saddle as 635 mm or above, the maximum value of d can be 90 mm

For a bicycle with a height of saddle less than 635 mm, the maximum value of d can be 75 mm

Figure 5: Brake Lever Dimensions (European Standards, 2006)

Manufacturing Directives for Wheels and Wheel assembly

For wheels which are intended for the rim brake the maximum allowable run-out (i.e the maximum variation in the position of rim) is 1mm when it is measured perpendicular at a suitable point on the rim and in the direction perpendicular to the axle. The wheel assembly alignment in bicycle whould has at least clearance of 6 mm between the tyre and the fork or the frame element. (European Standards, 2006)

Figure 6: Wheel assembly (European Standards, 2006)

The European directives along with the standards for different parts and components also contains instructions for the manufacturers, some of these are as mentioned below: Every bicycle designed in any country should have the following set of instructions written in the country language:

It should have mentioned the use or the application for the bicycle is designed along with the hazard warnings in case of incorrect use

It should have the details about the bicycle preparation like adjusting and measuring the saddle height

It should have clearly informed notes about the correct levers for the front and the rare brakes

It should have a method recommended for adjusting the suspension system which is adjustable

It should have safe riding recommendations like helmets, checks for brakes, tyre etc

It should clearly indicate the total permissible weight which it can bear

The correct tension in the chain and the correct method for component assembling

General recommendations on Maintenance

2.5 Future of Bicycle

The future of the bicycle is very promising in the near future. There are many reasons behind it, but the major one apart from the developments bicycle technology is the environmental pollution because of the fueled vehicles which is continually encouraging and demanding for the use of non fueled vehicles like bicycle. (Mathew, 2008) There also had been a lot of developments in the technology of the Bicycles in 1990s and 2000s and these have led to some advanced vehicle designs like Human Powered vehicles. Most of the Human powered vehicles are a low-slung recumbents having more of aerodynamic characteristics than that of the conventional cycles which results in decrease of the drag and thus increase in the speed. Recumbents are also very safe and many of them have provision for weather protection or cargo room. Wim in 1990s developed hybrid of the automobile and bicycle called the Ecocar which had provisions for safety, weather protection, easy maintenance, speed, and comfort and luggage room. With the advent of the computer technologies the design capabilities of the designers and manufacturers has enhanced greatly and this can help in even better and acceptable designs of bicycle in future. (Mathew, 2008)