With the Winter Olympics ending this weekend, I couldn’t resist this story about simulated slapshots. The slapshot is the most difficult shot in ice hockey and it is all about power and speed. Indeed, the fastest slapshot puck was clocked at a blistering 175 km/h.

To do a slapshot, the player draws back their stick and then accelerates it down and forward, so the blade slaps the ice just behind the puck. As the stick strikes the ice it flexes, storing energy that is released when it reaches the puck.

In the 19th century hockey sticks were made from a solid piece of wood, but they broke easily. Players started using much stronger laminated wooden sticks, which made the slapshot possible. Fast forward to 2000, and players started using sticks made from composite materials that are even stronger and lighter than wood – so slapshot speeds increased.

Dynamic loading

Now, scientists at US-based Altair Engineering have used the company’s Radioss dynamic loading simulation to understand why composite materials offer hockey players an advantage. They found that a composite stick gives a higher degree of control over the puck when compared to a wooden stick. This allows more energy to be delivered to the puck from a composite stick. You can read more about the study here and watch the simulations.

A good hockey player has an intuitive understanding of  how to make a slapshot, in the same way that a good crane operator knows how to shift a load while preventing it from swinging back and forth. Cranes that operate on construction sites lift loads using a long cable. As a result, the load is a pendulum that has a natural frequency of oscillation. When the load starts to move horizontally, it will naturally start to swing back and forth – but a good operator will know the tricks required to dampen the motion.

Now, the physicist Stephan Schlamminger at NIST in the US has stumbled upon these tricks while he was developing ways to control the motion of torsion pendulums. These pendulums are used to make extremely precise measurements of the gravitational constant.

As Schlamminger was developing his equations he recalled a conversation he had many years ago with a fellow physicist who told him about the tricks that crane operators use to control their loads. He realized that he could adapt his equations to apply to cranes and has published a paper describing his findings. You can read more about his research here and also watch a video demonstration.