Fracture Mechanics

by YPU Admin on April 23, 2013


My name is Huw Woodward and I am currently in the second year of my PhD at the University of Manchester.


My research can be divided into two elements: fracture mechanics and computational modelling. Fracture mechanics is the study of cracks within structures. The presence of a crack within a structure can reduce its strength significantly and lead to its failure at loads much lower than would otherwise be expected. Be it the wing of an airplane or a high pressure vessel in a nuclear power station, understanding the behaviour of these cracks is vitally important to ensure their safe design. Computational modelling involves the use of computers to run mathematical models which predict the behaviour of complex systems. Engineers use computational modelling as a tool to analyse the behaviour of structures under different loads; for example, it can be used to predict the failure loads of a structure. My research focuses on developing a new method for the modelling of cracks within structures with the aim of improving on current techniques. My research is partly funded by EDF Energy so my research is particularly geared towards the study of cracks within high pressure pipes that are used in nuclear power stations.

In Depth

Due to current limitations in the analysis of fracture mechanics problems, power stations are over-engineered. This means that parts of the power station are designed to be much stronger than is necessary in order to account for the uncertainty that exists in the understanding of these cracks. Improving the accuracy of our models will allow for more efficient designs of these power stations, leading to improved safety standards and reducing costs.

Computational modelling might sound complex; however, it is based on a simple principle: a large and complex problem can be solved by dividing it into many smaller parts before solving each part individually. For example, analysing the stresses within a large structure such as a suspension bridge would be near impossible when considering the structure in its entirety. Imagine building a suspension bridge out of Lego blocks. Each Lego block is small, of a simple shape, and is therefore easy to analyse. Using a computer’s ability to solve thousands of simple equations very quickly makes it possible to analyse each block individually in order to build a solution for the entire bridge. This is essentially what is done when modelling a structure computationally.

My interest in computational modelling was sparked during my third year project as part of my undergraduate studies in Mechanical Engineering at the University. My project involved an attempt to computationally model a tornado. The project introduced me to the elegant techniques used to model problems of seemingly impossible complexity. The mathematics behind such techniques still fascinates me. The fact that my work will have real-world, practical implications adds to my motivation and is one of the reasons why I chose engineering over a science degree. Applying your knowledge to improve on our current capabilities is what engineering is all about!

Going further

The importance of fracture mechanics suddenly became apparent during the Second World War when problems occurred with the American-built “Liberty” Ships.

Due to some major design flaws some of these ships literally broke in half due to huge cracks that formed through the hull. This sparked a huge increase in the focus given to the study of fracture mechanics. You can read more about these ships at Bright Hub Engineering.

This video shows the simulation of a car crashing into a bollard. Towards the end of the video you can see how the complex structure of the car has been divided into many smaller pars of simple shape.  

For more information on many various Engineering-related topics, Bright Hub Engineering is a great resource. The Brightside Trust also has information about studying subjects that can lead to careers in Engineering. 

For further information about studying Engineering at the University of Manchester, the department website provides a lot of useful information. 

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