New modelling technique could avoid need for engineering prototypes
20 November 2013
A new modelling technique has been developed that could avoid the necessity of building costly prototypes used to test engineering structures.
Most engineering structures - for example, aircraft landing gear, jet engines and gearboxes - involve friction and impact among their components. Traditionally these harsh phenomena are difficult to design for and introduce a great deal of uncertainty in the final product.
The new research, undertaken by Dr Robert Szalai at the University of Bristol, offers an alternative view on this problem by providing a modelling technique that allows for more accurate predictions than methods currently available. The proposed method also offers a better understanding of contact mechanics, which might be used to achieve a better design.
“One of the greatest concerns of engineers is modelling friction and impact," says Dr Szalai. “Building prototypes to test engineering structures can be extremely expensive and this new modelling technique could mean a prototype does not need to be built.”
The University of Bristol's Professor Alan Champneys, says strongly nonlinear behaviour, such as stick-slip motion and impact, are a huge cause of uncertainty in engineering systems. “The findings from this paper provide a key breakthrough in research that is being pursued by a consortium of major universities and industrialists to address these problems as part of an EPSRC programme grant,” he adds.
In a paper, published in The Proceedings of the Royal Society A, the researcher presents a general mechanical model and describes a model reduction technique. The new model includes a memory term to account for effects that traditional models ignore. The study has also discussed the convergence of the method and its implications for non-smooth systems.
The derivation of the memory term is illustrated through the examples of a pre-tensed string and a cantilever beam. The paper uses the example of a bowed string and demonstrates the properties of the transformed equation of motion - in particular, its convergence as the number of vibration modes goes to infinity.
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