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Computer Simulation of Wear
We have created a unique computer simulation to model rail wear, and its development and improvement is ongoing. Currently, rail material is represented as a mesh of rectangular elements, and to mimic microstructure the material properties vary from element to element. Applied stress varies with depth and the elements accumulate damage and fail at different rates. Elements can be removed as the material fails to simulate wear. Failure is based on the extent of plastic deformation of the steel.
The wear model requires development to consider surface roughness, additional failure mechanisms, and to move to 3-dimensions from the current 2d software. |
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Modelling rail damage. Left: model. Right: micrograph |
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Boundary or Finite Element Modelling of Cracks |
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Cracking of metals is a major problem for railways. How cracks grow, and how fast, is being investigated using computer modelling and experimental testing. Rail-wheel contact forces drive much of the damage, but other issues such as welds, residual stress following rail manufacture, and maintenance techniques can also affect the rail life.
Opportunities currently lie in computer modelling and experimental testing to predict crack growth rates, and to understand how visible surface crack appearance is related to the internal state of the rail. |
Modelling a series of 3 semi-circular cracks in a rail |
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Ageing Population
An ageing population is a commonly talked about theme and this is for good reason. The world population over the age of 65 is expected to be more than double from 357million in 1990 to 761million by 2025. This increase in elderly people could easily become a burden on all aspects of society i.e. healthcare, housing, economics etc. These sorts of statistics have led to a large volume of research into the ‘ageing population’. Our area of interest is in the benefits of development of assistive technologies and aids. |
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The Problem
Many old people function well and maintain their health effectively but there are many more that don’t. The cost of care of elderly and frail people increases dramatically with the increased level of assistance required. In the UK alone there are approximately 12million people over the age of 65 and approximately 95% of these live in homes on their own. Of these 12million 28% require some help with domestic tasks or personal care. It makes sense to improve the quality, effectiveness and efficiency of this care to avoid any loss of independence.
The Aim
The aim of our research is to develop assistive technologies which will aid both the elderly and their carers, technologies that will allow them to remain independent and within their own homes. Areas of interest are remote monitoring, home sensors i.e. to detect if a patient has fallen and other smart technologies. |
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The Ageing Population |
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Cataract Eye Surgery |
A cataract is the clouding of the eye lens and unfortunately it is due to the ageing process and is inevitable. It will happen to us all!
Currently the most popular technique for cataract surgery is Phacoemulsification. This involves inserting an ultrasonic tool into the eye which the surgeon uses to dig grooves in the cataract which are then used to help break up the cataract. Using the same tool the broken up cataract is removed using suction and a new folded lens is inserted which unfolds within the eye to finish the operation. The patient is conscience during the operation with local anaesthetic in the eye. |
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Cross-section of eye showing Phacoemulsification tool inserted |
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The Problem
The area of interest to the group is what happens when things go wrong! It is possible to damage the sensitive parts of the eye using the Phacoemulsification tool if the grooves in the cataract are dug too deep. This occurred in 4.3% of cases in ’97-98. This equates to 11,000 operations – a lot! |
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The Aim
The aim of our research is to reduce this complication rate by providing real time feedback to the surgeon as to how far he has dug into the cataract. Almost like a car parking sensor which beeps more frequently as you approach a stationary object. Currently an image analysis approach is proving successful and a patent application has been filed. This project involves collaboration with a famous surgeon in the UK. |
Eye clamped during cataract surgery |
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