Smart materials and composites

Define what is meant by the term ‘Smart material’? In your answer name a specific smart material and describe a useful physical or mechanical property it has. (2 marks)
- A smart material is a material that changes its form or characteristics when either heat or electricity is applied. One example of this is Nitinol, which is a smart memory alloy (comprised of nickel and titanium), which can be dis-formed then when heated returns back to it's original shape. 

Name a specific smart material and an application for that smart material. (1 mark)
- Thermochromic pigments on the surface of coffee mugs to tell you when the mug is warm.

Define what is meant by the term ‘composite material’ and using examples, describe the general advantages of composites over traditional materials. (2 marks)
- A composite material is something made from several constitutional materials to create a material that has greater propertied than any of the original materials. 


Explain how the structure of plywood gives the material strength. (2 marks)

- Plywood is a laminated material where the grain in the layers are facing opposing directions. This gives the wood strength in all directions. The adhesive glue also aids in the structural integrity of the timber. 

Smart Materials

Steam Bending

Steam Bending:

Most woods can be steam bent. Steam bending is a rather simple process that is exactly what it sounds like, bending wood with steam. Some of the best woods to bend are blackberry, white oak, red oak, magnolia, walnut, pecan, hickory, beech, elm, and birch. Soft woods do not tend to bend as well.

It works by re-adding moisture to the fibres in the wood, this allows them to bend and flex, and therefore they can be moulded. Moisture is added by putting the wood in a rack in a cylinder filled with steam from a pump. There is a general rule of thumb with steam bending, and that is for every inch of wood equals one hour in the steam being cured. So if a piece of wood is five inches thick then it requires five hours in the steam before attempting to bend. After the wood has been cured for the adequate amount of time the wood is removed from the steamer and is clamped around a mould. The moisture is then sucked back out of the wood; this is done through kiln drying. The drying “locks” the fibres in their position bent around the mould. This means the wood retains its bent shape.

The dangers of steam bending are that if the wood is bent before properly cured then it could be at risk of breaking. It also needs to be bent with the grain; if bent against the grain or the wood contains knots then it could also break whilst bending.

The process is used on a small scale making jewellery and one off furniture. But traditionally it was used on a larger scale to form the primary structure for hulls of boats. 

Chair Project

Types of wood, Seasoning and Finishing.

Assignment 1: "I should never have purchased"

Sony Xperia Play

My phone contract was coming to an end and it was time for an upgrade. Admittedly, I was upgrading from a Nokia so anything would be better, or so I thought...

Earlier that year I attended “Gadget Show Live” at the NEC. Where a vast array of high end tech manufactures come together in one big hall to show off their latest upcoming products. The notorious technology tycoon, Sony, had a rather unusually large stand as they were showcasing their all new Xperia Play, the “revolutionary” step in mobile gaming technology by incorporating a slide out PSP style gamepad into a standard Sony smart phone. I was amazed by the concept and sure enough a few months later, made the purchase.

The faults were immediately noticeable from the first start-up of the handset. Upon unpacking the phone from its box I noticed the horrific button placement. The power button was situated below the level of the casing, making it very fiddly to awaken the phone. Then there was the issue of where the volume buttons were positioned, rather oddly, in the middle of the side of the phone, exactly where your palm rests whilst holding the handset. Causing the slightest change in grip to alter the volume, occasionally to max, giving you a rather unwelcomed shock whilst listening to music through the provided headphones (which were also crap).

Button placement aside, there were other faults too. The PSP panel didn’t quite line up with the main phone body, and the sliding mechanism was quite loose. This made the phone very uncomfortable to hold as the edges of the product were noticeable, and not “seamless” as the product description described. Furthermore every time the sliding joint moved, the phone detected this movement and launched the mediocre media screen, which was to graphically intensive for the under specified Xperia to handle, Causing it to glitch and inevitable, crash. The result of the crash called for a reboot of the phone which seemed to take longer than necessary.

All of these faults seemed to be linked to a lack of market research, poor quality control and assurance checks and lastly subpar manufacturing processes resulting in misaligned parts.  

The conventional plug and the new design plug are made from ABS (Acrylonitrile butadiene styrene), a very common thermoplastic. This material is suited to the role of a plug as it has the following properties:

•          It has high impact resistance so it can withstand the knocks delivered from common use.
•          Is a very good electrical insulator to protect the user from shock.
•          It is also recyclable as it is a thermoplastic. This is a very important factor as the amount of plugs produced is so large, if they were un-recyclable the impact on the environment would be significantly greater.

The manufacturing process used to mould these plugs is injection moulding. This is where a thermoplastic is heated into a liquid state and then forced into a split mould at high pressure using a hydraulic press. The advantages of this are that any faulty items can be put straight back into the hopper, and re-moulded. Also any shavings or waste product can be put back in so the process has minimal waste. Also the moulds can be used hundreds of times before they need replacing. The only disadvantage is that the split moulds are very expensive to replace once worn down.

The plug could have been redesigned as there were flaws with the old, traditional design. The primary flaw in the old design was that the plug could not be easily stored, and very often took up a large proportion of the packaging. Another flaw with the traditional design is extension cords were very large and two plugs could not be compacted into a small space, taking more materials to produce extension leads and moreover, not as convenient for the user. The new design eliminates these issues by the folding design making storage and packaging simple. And the clever folding design allows multiple plugs to be connected into the same area as one traditional plug, saving on materials and rendering them more usable and convenient for the user.