The Science of Hockey: A Brief Intro

[Gustav 6,415]

What's good, VHL! I'm here with an article that I'm really excited to write...which I'll probably follow up with a much longer sequel eventually...because this week is my exam week and I'd rather earn my points and get the hell out than spend hours on end writing up a few thousand words for all of you (as much as I'd like to).

 

For those of you who don't know, I'm currently an engineering student. While I don't claim to be a scientific expert, I at least have exposure to some interesting concepts that can be applied to the sport of hockey if I think about them hard enough. And sitting here simultaneously thinking about something I can easily write about and stressing out over exams led me to wonder--why haven't I made that an article yet? That's what I'm going to do here, where I talk about stick design in a way that also allows me to boil down some key concepts that would be useful for me to know in the coming week.

 

Before we begin, some key terms:

Elastic Deformation: a material changing its shape in a way which can be easily reversed (like stretching a rubber band, it just pops right back to where it was).

Plastic Deformation: a material changing its shape in a way which cannot be easily reversed (like bending a fork--it doesn't bend back when you let go of it and even if you try to bend it back it won't be exactly where it was before).

 

That's all I'll mention for now for the sake of making this article digestible. There are some other words to talk about, but that's all we need to know for now.

 

Hockey sticks, as most here will know, originally started out as pieces of wood. Wood was the standard in many pieces of sporting equipment back in the day, from hockey sticks to golf clubs (as well as baseball bats, which are still wood today unless you're a cheater and you fill yours with cork). For quite some time, wooden sticks were what they were, and until Bobby Hull and Stan Mikita popularized curved blades, they were the most basic sticks imaginable. But then the '80s rolled around, and Wayne Gretzky brought about a new era of aluminum-shafted sticks. Fifteen years later, materials scientists had started making sticks out of composite materials (or, in other words, "throw tiny fibers of one thing inside another thing"--which can actually drastically improve the properties of the main material if done right). Composites continue to be used today, with different compositions being experimented with and improved upon constantly, most notably with modern carbon-fiber designs.

 

A criminally obsessed-with feature of modern sticks is their "flex"--i.e. the amount of force upon the stick necessary to make it bend a certain amount. Lower numbers mean less force (and more bendy), higher numbers mean more force (and less bendy). So why does this matter in the context of science?

 

 

This is what's known as a stress-strain curve. Simply put, stress is the amount of force on an object, and strain is how much that object's shape changes under a given stress. A hockey stick's stress-strain curve will probably look the most like the blue one here, line B. Line A is a very brittle material (like diamond), while line C is a very stretchy one (like rubber). The vertical dashed line at the end of each curve is the point where the material will break (so material A doesn't stretch a lot, material B stretches a bit, and material C will stretch out a ton before it breaks).

 

Remember those two terms I threw out there earlier? Only the part where the line is straight, not curved, is the part where elastic deformation is happening. When the line starts curving, that's when the object's shape starts changing permanently, and we don't want that in a hockey stick.

 

So, there's a trade-off to be made as the only real "usable" portion of the curve is the straight one. Do you want a stick that bends a lot and may give you a bit of an advantage with the speed of your shots? It may not tolerate as much stress before you break it. If you're a smaller forward who likes wrist shots, you want your stick's stress-strain curve to be somewhat between B and C here--you can build up some nice extra energy on your regular shots by having the stick bend a bit more, and less stress on your stick before it bends permanently or breaks isn't a major concern. But what if you're a big, powerful defenseman? You're taking a lot of slap shots and putting all your weight into them, so you don't want that stick breaking on you. You want your stick to be between A and B on this chart. It's not going to bend like that forward's stick. It's actually going to feel more fragile because of that. But it isn't--it's actually stronger because you can put more stress on it before it snaps, even if it doesn't bend much before it does.

 

See how line A reaches a higher point than B or C? It's going to be very hard to break something with that curve, but it's also going to be impossible to bend it because the material would rather break than bend. Same with line C--the material is actually so eager to bend that rearranging itself so it's able to bend actually takes away some of the stress on it. For the purpose of illustration here, think of line B as a nice happy medium (and the reason why I said that's your average hockey stick). It will bend a little, and it can stand up to a decent amount of force.

 

Hopefully this is a nice and understandable read, there are a few other interesting concepts I have in mind but there are also better things I could be doing this week. See you after exams.

 

 

1,001 words; guess I have next week off too but I won't complain about that.

[a_Ferk 766]

Pretty informative read Gustav, I think it gave a lot of insight towards the science of hockey sticks for those that have never played before. Don't really have any criticisms so just wanted to add that the certain amount that flex expresses is the pressure required to bend the stick one inch. Usually a flex around half your body weight is a good choice but it all comes down to position and personal preference. 10/10 article

[Gustav 6,415]

Week 2