The group Presentation

Here is the presentation slide containing the information used for the presentation session on Wednesday.



Just want to congratulate the Team on a brillant perfomance and hope that it will be a success.

Our final Crane model

After a long period of designing and re-designing we finally finished with out crane model. below is a picture of of the final module.

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

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

• 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.

With that in mind, different percentages of each material, is used to create the ideal steel for the job.



















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.

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)

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.

Final Concept Sketchs

Looking at picture 1.
this was the rough sketch of the final design stipulating what sort of components to use and where to use them.




Picture 2
shows the side of the concept crane design ( upper half). this bit conatains, an eye bolt to help support the steel cords which will be used for pulling heavy objects.



Also below are sketches of the side views for the top beam indicating how the the cord will be passing through.



Picture 3
this indicates the meta bars that will be used when the crane is in operation, to help move the crane around after objects have been lifted.
The base of the crane also shown without the outriggers.

Note:
Sketches produced by the Arnold ( Chief Designer)

Steel Rope.

As there is a winch system within our crane, we shall have to use a strong type of steel rope, to hoist our load. We have previously stated we shall be using stainless steel. As it is a 'rope' we cannot just buy steel in a rope form. Instead, to achieve these desired results, a special blend of steel is produced, giving it strength, and ductility. When this is made, several of these rolls, or strands, are woven together, around a typically steel core, to produce one large 'rope'. By doing this, it enables the user to have extra support.

Ropes are favoured now due to chains. This is due to the fact they have a higher reliabililty compared to metal chains. Flaws in chains can lead to disaster, i.e. a dropping of the load. With wires however, the flaws do not make much of an impact.
The flexibililty of the rope is critical in our crane. The rope can then be wound around a cylindrical barrel, to lift a load, and unwound to put down a load.






















Above, we can see the wires, which are bonded together to form a strand, which is wound together with other strands to form the rope.

A little inspiration...!

http://www.youtube.com/watch?v=pqSFxZV6OvY&feature=related