Leipzig: meat, no vegetables and Sports Engineering

On the 18-20th November, Leipzig (Figure 1) in East Germany played host to the ANSYS Conference & 27th CADFEM Users´ Meeting. John Hart and Tom Allen from the Sports Engineering Research Group were in attendance, leaving behind cold wet Sheffield in exchange for cold wet Leipzig. ANSYS produce Finite Element (FE) and Computational Fluid Dynamics (CFD) software. FE software is generally used for analysing mechanical problems such as a football impact, CFD is generally used for aerodynamic problems such as modelling the flow around a skeleton bobsled.
Figure 1. Leipzig

The conference was held at the impressive Leipzig Messe (Figure 2) and held over an epic 3 days. Day 1 mostly consisted of keynotes spread over a marathon 10 hrs, day 2 the user’s got to present, whilst day 3 was given over to software based workshops. The conference was held in both German & English, giving us ample opportunity to improve our technical German abilities, and to perfect the “confused don’t know what is going on” look.

Figure 2. Leipzig Messe

The keynotes from the ANSYS bigwigs were very informative in terms of recent updates to the Computer Aided Engineering (CAE) software, as well as providing an insight into the direction things are heading in the world of engineering simulation. It appears that FE and CFD are moving ever closer together into a single piece of software. Sports Engineers may soon be able to analyse 1) the aerodynamics of a golf club, 2) the impact of the club with the ball and 3) the aerodynamics of the ball, within a single piece of software. Another area which caught my interest was the introduction of acoustic analysis into the FE software. At the 2008 International Sports Engineering Association (ISEA) Conference, Head revealed that they engineer their tennis rackets to produce a ‘sweet’ sound upon impact with the ball. Their reasoning being that this sound can influence the perception of the user and increase their satisfaction in using the product.

The 2nd day of the conference was our time to shine. My presentation on modelling tennis rackets with FE (Figure 3) was scheduled at 10 am while John had been given the 4.40 pm graveyard shift to showcase his work on using CFD in bicycle design.

My presentation was on a comparison between FE modelled shots against actual shots from the 2006 Wimbledon Qualifying Tournament. I demonstrated that the FE model predicted the rebound velocity of the ball to within 1 m/s of the actual tennis shots. The model can now be used to determine the effect of racket parameters, such as stiffness, on an actual tennis shot.

Figure 3. Finite element model of a tennis racket

John presented some very interesting work on the aerodynamics of Planet-X road bikes (Figure 4). He outlined the history of CFD in sport, highlighting how the techniques were pioneered by Formula 1 and America’s Cup teams. More recently the technology has trickled down to elite sports team and now even small companies such as Planet-X are utilising the software.  When asked;

Why are you concerned with the aerodynamics of the bike, when approximately 70% of the drag comes from the rider?

John explained that road races can come down to 1/100th of a second and any improvement in aerodynamics, however small, can be decisive. John also highlighted the compromise which must be made between the optimum riding position and aerodynamics.

Figure 4. Computational fluid dynamics simulation of Planet-X road bike.

Following the final session we headed off to the Moritzbastei for the conference dinner (Figure 6). The Moritzbastei is a series of 16th century Saxony vaults and cellars that have been turned into a popular venue for concerts, plays, exhibitions, or just a good party. As ever, at any of these events held in Germany, there was plenty of German beer to sample, along with meat, meat, and well more meat! As we sampled the range of German beverages and cuisine on offer we discussed the finer points of CAE in sports technology, what an evening.

Figure 5. Party time in Leipzig



About Dr Tom Allen

Dr Tom Allen is a lecturer in engineering design at Sheffield Hallam University. He leads the University's BSc (Hons) Sports Technology course and is the associate editor of Sports Engineering.

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