Material Selction Essay Example for Free

Material Selction Essay Park bench A park bench isn’t just for parks. It is an essential component of any public outdoor (or indoor) area. The 3 material I chosen ( wood concrete steel) These park benches provide strength and durability with a strong steel skeleton and high quality UV and weather resistant thermoplastic coating. One of the most popular bench styles, the thermoplastic coated steel park bench comes in a range of styles and colors. The thermoplastic coating protects the steel for years to come, and is maintenance and corrosive free. Made for the widest range of applications, these benches can be portable as well and permanent installs. Commercial park benches made with wood are always a top seller. Made usually of cedar, or pine, wood park benches offer strength and durability, reinforced with a welded metal frame construction for a long life. Wood is the popular choice also for its classic styling. When people think park bench, they will more than likely visualize a wood slat park bench with back and arms in an unfinished cedar nestled in a shady spot under an oak tree. This is obviously a great solution for a park, or outside of a mall but I would not recommend it for any city transit area. Other materials, like powder coated steel are better performers for high traffic. Concrete Park Benches are an inexpensive solution to a high traffic area. Dense and strong, anything concrete will last a long time and is ideal for parks, schools, bus stops, corporate break areas and rest stops, and other various street scapes or public areas. It is also resistant to vandalism and thievery due to its inherent density and bulk. It would be strenuous to attempt to move or damage one of these, making a concrete park bench the perfect solution for a permanent install. Hip joint The human hip is a ball and socket joint. This means that the top of the leg bone, the femur, is rounded and fits into the socket of the hip. This joint may need to be replaced if it has worn away, broken, or become chronically painful in some way. The process involves replacing the hip joint with 3 artificial parts, cup, ball, stem: Cup The cup is the most vital part of the hip joint process as the other 2 parts is dependable on the cup being good thus the material must not only be tough and strong but resistant to corrosion, degradation, and wear-.I chose the material ultra-high density polyethylene for the cup component in because of its outstanding toughness cut and wear resistance and its excellent chemical resistance. Fermoral ball – I chose the ceremaric material Zirconia for the head (ball) component in because of its Strength and Longevity, Zirconia is virtually indestructible ans should last a life ti. itcan be polished to give a very smooth surface and have a much lower wear rate than metal on polyethylene. Also using ceramics over metals for hip replacement parts are to do with the inherent biocompatibility of ceramic materials. Being highly oxidised, they are very inert and so the risk of any reactions with the host is negligible. However As with everything in life, all these benefits come with a price. Zirconia is very tough, which is good until you consider the abrasive effect of the material against the other compnenets. Fermoral stem – I chose the alloy material titanium for the stem component because not only does it have the combined properties of being light and strong it also allow for movement of the artificial hip joint with a minimal amount of friction. In addition, titanium are long lasting, strong and resistant to corrosion, degradation, and wear. Therefore, they will retain their strength and shape for a long time. Resistance to wear is particularly significant in maintaining proper joint function and preventing the further destruction of bone caused by particulate debris generated as the implant parts move against each other. However titanium is quite expensive.