Olympians expect top-notch performance from their minds and bodies, but they get crucial advantages from the very best equipment for their sports and the weather conditions they’re competing in. Skis, for example, must stand up to near-constant changes in stress during races.
The ideal ski provides a stiff and rigid platform for skiers’ boots to attach to, flexes to carve through turns, doesn’t break under the pressure of jumps and landings and is light enough not to slow the athlete down. But that’s not all: Skis must resist damage from collisions, absorb vibrations from icy conditions and withstand the temperature extremes and intense sunlight common in mountain environments.
That’s a lot to ask of a single item. The first skis were made of strong, flexible ash wood, but technology has found ways to do much better. Today’s materials design and construction processes are closely guarded industrial secrets, specific to individual ski companies. But I and other materials experts know that the essential components and methods are very similar: All skis are like sandwiches, stacking separate layers of different materials with all those separate properties into a single item, a competition-class ski.
Advanced materials for extreme conditions
Ultra-high molecular weight polyethylene is a highly engineered plastic often used in high-strength ropes as well as in artificial hip and knee implants. It’s tough, bends and flexes a lot without breaking, resists scratches, retains its properties across a range of temperatures and has tiny microscopic pores across its surface. When it’s used as the base layer of a ski, those microscopic pores act like a sponge into which racing wax is melted to fine-tune the ski’s contact with whatever the snow conditions are.
The sides of the ski base are made of high-strength steel alloys that are heated and processed to meet the demanding conditions of skiing. These processes make the steel resistant to rust and able to be sharpened like a knife. The steel needs to hold its edge to carve through snow and ice while flexing with the rest of the ski without cracking or breaking.
Inside the ski
On top of the base is a complex layer in the ski sandwich, an element itself called a “sandwich panel,” made of similar materials and with the same techniques as those used to build spacecraft, aircraft and performance race cars. The center of the sandwich is a core material surrounded by fiber-reinforced composites.
The cores of ski sandwich panels can be lightweight titanium alloys, polymer foams similar to Styrofoam coffee cups or different kinds of woods – such as maple, oak, aspen or poplar. These different plastic, wood and metal materials are layered and combined to tune the ski to the desired levels of strength, stiffness, ability to twist and vibration-damping, all with as little weight as possible.