I believe as the project manager of this group that our project has the required strengths to undertake relief work as contracted. The crane has been designed with quality and tough materials but at the same time also keeping the costs of the materials low.
The crane design has been taught out very carefully to make sure it meets the need of the tender. The design conquers all the aspects; it is small enough to fit in a 4x4, measuring at around 3x2 meters.
It can easily be moved around by hand also keeping health and safety regulations in consideration.
Special training is not needed with the use of this crane as it has designed while considering that it can also be used by non-professionals, although it can be provided at an extra cost.
I feel our project has meet the needs of the tender and its robust enough to be successful although there still might be few weakness but are not very significant.
I would like to thank all the team members of their brilliant effort towards this project and hopefully this project will be successful
If you guys would like to input additional strengths please comment below.
Friday, 23 April 2010
Thursday, 22 April 2010
Financial Report (2)
Looking as the whole construction of the emergency crane is to supply a solid crane that Non Governmental Organisations (NGO’s) can use to after natural disasters occur. Therefore it is key to keep profits to a minimal or if possible 0% as the cranes will be used for a good cause. The crane will be based on the concept of simply assembly of interchangeable components (Kit parts) which are essential for repair and improvement processes in order to prolong the crane’s shelf life.
Our simple innovative design means there a reduced number of parts needed, as well as the less number of skilled labour required in the construction of the crane. This means that even a team of 3 engineers all working on specific areas can fully build the crane from scratch bringing the whole production cost down giving our team a tremendous advantage over the market competition.
Labour includes
-Quality Control
-Assembly
-Welding/Bolting
-Polishing/Painting
-Testing
It is very hard to put a cost on labour but with asking around and receiving quotes whilst making aware of the good cause the crane will be serve the: Total Labour Cost Of One Crane should be £ 300
(this includes workforce labour plus machinery and materials required to do the job)
Summary
| Cost Of x1 Crane Kit | £ 680.76 |
| Cost Of x1 Cranes Labour | £ 300.00 |
| Subtotal | £ 980.76 |
| | |
| Total Cost Of x100 Crane | £ 61268.40 |
| Total Cost Of x100 Cranes Labour | £ 30000.00 |
| Subtotal | £ 91268.40 |
Financial Report (1)
The majority of our crane will be made up of steel due to its relative good strength. Steel comes in different forms namely Carbon Steels, Alloy Steel, Tool Steels and Stainless Steels which all vary in price and will be incorporated into various parts of the crane. For the construction of our crane we will be looking at obtaining high quality materials at the lowest available price.
Below is an idea of the typical cost of producing a single fully working model of the crane.
The cranes kit, including cost of each part:
6x L Triggers for Base
£90.00
4x rubberised Steel Handle Bars
£60.16
1x Stainless Steel Rope and Winch system
£67.50
1x Jib Construction System
£105.00
Pulley System
£50.00
1x Hydraulic
£45.80
1x Rotating Base System
£214.03
1x Hook
£48.00
TOTAL COST OF x1 CRANE KIT = £ 680.76
If our team is to win the invitation to tender then the cost will become:
TOTAL COST OF x100 CRANES = £ 68076.00
TOTAL COST OF x100 CRANES at 10% DISCOUNT = £ 61268.40
(The costs quoted above exclude any human/machinery labour required in the construction of the crane)
Reference websites used in estimation of costs
http://www.apluswhs.com/
http://www.metals4u.co.uk/
http://www.midlandwirecordage.co.uk/
http://www.meps.co.uk/index.htm
Below is an idea of the typical cost of producing a single fully working model of the crane.
The cranes kit, including cost of each part:
6x L Triggers for Base
£90.00
4x rubberised Steel Handle Bars
£60.16
1x Stainless Steel Rope and Winch system
£67.50
1x Jib Construction System
£105.00
Pulley System
£50.00
1x Hydraulic
£45.80
1x Rotating Base System
£214.03
1x Hook
£48.00
TOTAL COST OF x1 CRANE KIT = £ 680.76
If our team is to win the invitation to tender then the cost will become:
TOTAL COST OF x100 CRANES = £ 68076.00
TOTAL COST OF x100 CRANES at 10% DISCOUNT = £ 61268.40
(The costs quoted above exclude any human/machinery labour required in the construction of the crane)
Reference websites used in estimation of costs
http://www.apluswhs.com/
http://www.metals4u.co.uk/
http://www.midlandwirecordage.co.uk/
http://www.meps.co.uk/index.htm
Benefits of our crane
Innovate high-performance
applications with versatile Optim
• Achieve higher payloads for lifting and transportation applications.
Ruukki is the only supplier of very thin ultra high-strength steels
from 2.5 mm.
• Create more innovative applications with laser-welded thin, wide
sheets and a broad selection of high-strength sections and tubes.
Create good-looking end-products
with Optim, which has great workshop
capabilities
• Enjoy painless forming of Optim thanks to its minimal yield strength
variation and high thickness accuracy.
• Benefit from easy welding thanks to low alloying of Optim. Increase
welding speed with thinner gauges to save time and money.
• Benefit from excellent surface quality and flatness with our unique
production processes
- direct quenching
- powerful levelling capabilities both for heavy plate and
cut-to-length lines
applications with versatile Optim
• Achieve higher payloads for lifting and transportation applications.
Ruukki is the only supplier of very thin ultra high-strength steels
from 2.5 mm.
• Create more innovative applications with laser-welded thin, wide
sheets and a broad selection of high-strength sections and tubes.
Create good-looking end-products
with Optim, which has great workshop
capabilities
• Enjoy painless forming of Optim thanks to its minimal yield strength
variation and high thickness accuracy.
• Benefit from easy welding thanks to low alloying of Optim. Increase
welding speed with thinner gauges to save time and money.
• Benefit from excellent surface quality and flatness with our unique
production processes
- direct quenching
- powerful levelling capabilities both for heavy plate and
cut-to-length lines
A little more about Steel...
The material Steel has been used throughout this blog. I think it's about time I clarified what Steel exactly is!
Steel is not just a natural material. It is in fact, an alloy. The term Alloy, is used to describe a material that has been made up of various other materials. Steel consists mainly of Iron. Iron is not that strong as a single substance, by adding other metals to this iron, we produce steel. This steel can be up to a thousand times strong than the original steel!
Above, a photo of pure Iron.
I mentioned the Iron is bonded with other materials, Carbon essentially. Steel typically will have a carbon content ranging from 0.2% to 2.1% pending on weight and quality. Carbon acts and a hardening element, this prevents dislocations in the atomic structure.
Other materials added into the Steel alloy, usually contain the following, Manganese, Chromium, Vanadium and Tungsten. Each are usued to offer different properties to the steel. These can vary from
A sword, for example, must be lightweight, have a high tensile strength, but, ideally, not bend! (Where as a spring, should be very ductile!)
Steel is not just a natural material. It is in fact, an alloy. The term Alloy, is used to describe a material that has been made up of various other materials. Steel consists mainly of Iron. Iron is not that strong as a single substance, by adding other metals to this iron, we produce steel. This steel can be up to a thousand times strong than the original steel!
Above, a photo of pure Iron.
I mentioned the Iron is bonded with other materials, Carbon essentially. Steel typically will have a carbon content ranging from 0.2% to 2.1% pending on weight and quality. Carbon acts and a hardening element, this prevents dislocations in the atomic structure.
Other materials added into the Steel alloy, usually contain the following, Manganese, Chromium, Vanadium and Tungsten. Each are usued to offer different properties to the steel. These can vary from
- Hardness - Ability to stop deforming when a force is applied.
- Ductility - Ability to deform elastically without fracture
- Tensile strength - Amount of stress the material will take without rupture.
A sword, for example, must be lightweight, have a high tensile strength, but, ideally, not bend! (Where as a spring, should be very ductile!)
Stress and Strain Behaviours
My colleague has published a post making a general comparison of Steel, against, Aluminium. I will be looking to develop on this matter furthermore, so, as a group, we can be sure we're making the right choice.
As mentioned, mechanical properties vary from low strength alloys, to medium and high strength alloys. Regardless, there is no such aluminium alloy that compares to the strength of steel. But, as mentioned beforehand, strength is not alloys a deciding factor when selecting materials.
Below, there is a graph showing the stress strain curve (for, temperatures from -30c to 80c) you can see how each alloy, behaves very, very differently. Because of this, we shall have to select materials carefully.
As you can see from the above diagram, an important factor, steel is linearly elastic, up the 0.2% limit, however, aluminium, the proportional limit fp, is lower then fo.
As mentioned, mechanical properties vary from low strength alloys, to medium and high strength alloys. Regardless, there is no such aluminium alloy that compares to the strength of steel. But, as mentioned beforehand, strength is not alloys a deciding factor when selecting materials.
Below, there is a graph showing the stress strain curve (for, temperatures from -30c to 80c) you can see how each alloy, behaves very, very differently. Because of this, we shall have to select materials carefully.
Heat, does have a big factor also. Heat can have an impact from the weilding taking place in the manufacturing process, but also from the outdoor temperature. Aluminium's suffer more damage than Steel's, especially heat treated aluminium alloys. This results in lower actual strengths than metals in a stable environment.
(NB. If using mechanical fasteners, instead of weildings, there will be no heat damage)
(NB. If using mechanical fasteners, instead of weildings, there will be no heat damage)
As you can see from the above diagram, an important factor, steel is linearly elastic, up the 0.2% limit, however, aluminium, the proportional limit fp, is lower then fo.
Wednesday, 21 April 2010
beam's properties
Elastic Modulus 210000 N/mm^2
Poissons Ratio 0.28
Shear Modulus 79000 N/mm^2
Thermal Expansion Coefficient 1.3e-005
Density 0.0078 g/mm^3
Thermal Conductivity 43 W/m K
Specific Heat 440 J/kg K
Tensile Strength 399.826 N/mm^2
Yield Strength 220.594 N/mm^2
Poissons Ratio 0.28
Shear Modulus 79000 N/mm^2
Thermal Expansion Coefficient 1.3e-005
Density 0.0078 g/mm^3
Thermal Conductivity 43 W/m K
Specific Heat 440 J/kg K
Tensile Strength 399.826 N/mm^2
Yield Strength 220.594 N/mm^2
The Pulley
Pulleys are a better way to lift large masses onto tall heights and are examples of simple machines.
The types of pulleys that had been researched included:
- Fixed pulleys:
- Movable Pulleys
- Compound Pulleys
- Block and tackle
For the project we decided to use the the fixed pulley system. This is a fixed or class 1 pulley with a fixed axle. That is, the axle is "fixed" or anchored in place. A fixed pulley is used to change the direction of the force on a rope (called a belt). A fixed pulley has a mechanical advantage of 1. A mechanical advantage of one means that the force is equal on both sides of the pulley and there is no multiplication of force
NOTE that
The number of pulleys used in a system may increase or decrease the mechanical advantage of the system. Generally, the higher the mechanical advantage is, the easier it is to lift the object.
This means no matter how easy it is to use the pulley system, the system itself is not very efficient due to the force of friction. For example, one has to pull two meters of rope of cable through the pulleys in order to lift an object one meter.
The types of pulleys that had been researched included:
- Fixed pulleys:
- Movable Pulleys
- Compound Pulleys
- Block and tackle
For the project we decided to use the the fixed pulley system. This is a fixed or class 1 pulley with a fixed axle. That is, the axle is "fixed" or anchored in place. A fixed pulley is used to change the direction of the force on a rope (called a belt). A fixed pulley has a mechanical advantage of 1. A mechanical advantage of one means that the force is equal on both sides of the pulley and there is no multiplication of force
NOTE that
The number of pulleys used in a system may increase or decrease the mechanical advantage of the system. Generally, the higher the mechanical advantage is, the easier it is to lift the object.
This means no matter how easy it is to use the pulley system, the system itself is not very efficient due to the force of friction. For example, one has to pull two meters of rope of cable through the pulleys in order to lift an object one meter.
Corrosion
Corrosion Theory
Humans have most likely been trying to understand and control corrosion for as long as they have been using metal objects. The most important periods of prerecorded history are named for the metals that were used for tools and weapons (Iron Age, Bronze Age). With a few exceptions, metals are unstable in ordinary aqueous environments. Metals are usually extracted from ores through the application of a considerable amount of energy.
Certain environments offer opportunities for these metals to combine chemically with elements to form compounds and return to their lower energy levels. A modern and comprehensive document on the subject is the second edition of the classic CORROSION BASICS textbook. Some excerpts of that document are used here.
Corrosion is the primary means by which metals deteriorate. Most metals corrode on contact with water (and moisture in the air), acids, bases, salts, oils, aggressive metal polishes, and other solid and liquid chemicals. Metals will also corrode when exposed to gaseous materials like acid vapors, formaldehyde gas, ammonia gas, and sulfur containing gases. Corrosion specifically refers to any process involving the deterioration or degradation of metal components. The best known case is that of the rusting of steel. Corrosion processes are usually electrochemical in nature, having the essential features of a battery.
When metal atoms are exposed to an environment containing water molecules they can give up electrons, becoming themselves positively charged ions, provided an electrical circuit can be completed. This effect can be concentrated locally to form a pit or, sometimes a crack, or it can extend across a wide area to produce general wastage. Localized corrosion that leads to pitting may provide sites for fatigue initiation and, additionally, corrosive agents like seawater may lead to greatly enhanced growth of the fatigue crack. Pitting corrosion also occurs much faster in areas where microstructural changes have occurred due to welding operations.
The corrosion process (anodic reaction) of the metal dissolving as ions generates some electrons, as shown in the simple model on the left, that are consumed by a secondary process (cathodic reaction). These two processes have to balance their charges. The sites hosting these two processes can be located close to each other on the metal's surface, or far apart depending on the circumstances. This simple observation has a major impact in many aspects of corrosion prevention and control, for designing new corrosion monitoring techniques to avoiding the most insidious or localized forms of corrosion.
Humans have most likely been trying to understand and control corrosion for as long as they have been using metal objects. The most important periods of prerecorded history are named for the metals that were used for tools and weapons (Iron Age, Bronze Age). With a few exceptions, metals are unstable in ordinary aqueous environments. Metals are usually extracted from ores through the application of a considerable amount of energy.
Certain environments offer opportunities for these metals to combine chemically with elements to form compounds and return to their lower energy levels. A modern and comprehensive document on the subject is the second edition of the classic CORROSION BASICS textbook. Some excerpts of that document are used here.
Corrosion is the primary means by which metals deteriorate. Most metals corrode on contact with water (and moisture in the air), acids, bases, salts, oils, aggressive metal polishes, and other solid and liquid chemicals. Metals will also corrode when exposed to gaseous materials like acid vapors, formaldehyde gas, ammonia gas, and sulfur containing gases. Corrosion specifically refers to any process involving the deterioration or degradation of metal components. The best known case is that of the rusting of steel. Corrosion processes are usually electrochemical in nature, having the essential features of a battery.
When metal atoms are exposed to an environment containing water molecules they can give up electrons, becoming themselves positively charged ions, provided an electrical circuit can be completed. This effect can be concentrated locally to form a pit or, sometimes a crack, or it can extend across a wide area to produce general wastage. Localized corrosion that leads to pitting may provide sites for fatigue initiation and, additionally, corrosive agents like seawater may lead to greatly enhanced growth of the fatigue crack. Pitting corrosion also occurs much faster in areas where microstructural changes have occurred due to welding operations.
The corrosion process (anodic reaction) of the metal dissolving as ions generates some electrons, as shown in the simple model on the left, that are consumed by a secondary process (cathodic reaction). These two processes have to balance their charges. The sites hosting these two processes can be located close to each other on the metal's surface, or far apart depending on the circumstances. This simple observation has a major impact in many aspects of corrosion prevention and control, for designing new corrosion monitoring techniques to avoiding the most insidious or localized forms of corrosion.
General Comparison of Aluminium and Steel
We have come to the conclusion as a group that our crane will either have to be made up of Aluminium or Steel whilst taking into account their respective weight, cost, and durability in the long run.
Similarities
To start with the similarities of aluminium and steel:
- Structural applications of aluminium and steel are mostly similar;
- Design problems/processes are similar so an identical approach is used;
- The design rules for aluminium and steel (EC9 and EC3) are purposely very similar, see the first two reasons.
Differences
However, there are important differences in physical as well as mechanical properties which have to be accounted for in the design process. The table on this page gives a comparison between the most important physical properties of aluminium and steel. The differences in properties, the consequences for structural behaviour and how to deal with that in structural design will be elucidated below.
First of all, the low density of aluminium is the main driver for using it in many structural applications. The high strength to weight ratio is the number one reason for the development of the aircraft industry. Although its low weight is a favourable property, it can in some cases be a disadvantage; for example with cyclic loading the ratio live load/dead load is disadvantageous as compared to steel and so fatigue must be considered early in the design stage.
The low density makes an aluminium structure prone to vibrations and in these cases the dynamic behaviour of the structure has to be considered. The Young modulus, E is important for the structural behaviour. Its value is about 1/3 that of steel, but contrary to density, this is a disadvantage compared to steel.
The above indicates that in designing aluminium structures, it is often not the strength, but in many cases the deformation, that is the governing factor. So in building and civil engineering it is frequently the alloy which does not have the highest strength that has to be considered.
The low Young modulus is also responsible for the higher sensitivity to stability problems in aluminium structures (buckling). The critical stress for buckling is linearly related to the Young modulus. Moreover, aluminium designs often have very slender, thin walled sections which make it even more important to consider their stability in designing structures.
Finally, there is cyclic loading, where the Young modulus is responsible for the lower fatigue strength of aluminium – circa half that of steel. This, in combination with the low density, means that fatigue design should be considered more carefully than with steel structures. Similar to the Young modulus is the shear modulus G which is also about 1/3 of that for steel. This means that the resistance against shear forces, shear deformations and shear stability (for example lateral torsional buckling of beams) can be an important aspect in the design.
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