When designing a snowboard, several properties such as edge
design, dimension, and force tolerance are taken into
consideration.
There are three types of sidewall layer design, as shown on the right. Layer designs are important because the surface area of snowboard edges change the ways in which a snowboard turns. The more surface area there is around the edge of a board, the sharper the turns a snowboard will make. It is then advisable that a snowboard made with a sidewall construction would be ideal for a beginning snowboarder. What causes this is a general principle of physics. The more area a certain force is being applied onto the surface, so is applied pressure (P = F/A). The increased amount of pressure allows the board to dig deeper into the snow, thus "grabbing" more snow as a normal force from the snow pushes the snowboarder and a smaller turning radius is achieved. Some snowboards are constructed with an edge with small surface area (cap construction) because it provides an lighter overall weight and performs better aerodynamically when advanced airborne tricks are performed. Higher end snowboards are designed with a mix of the sidewall and cap types of construction and is commonly known as the half cap construction. This type of construction is basically like a hybrid version of the two as the cap goes halfway down the edge and forms a sidewall down the bottom edge.
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*http://www.geocities.com/snowfactory/boardcomponents.html |
*http://www.eng.uab.edu/compositesLab/snowhome.html
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The resultant force acting on a snowboard (caused by gravity and the person riding the snowboard) is tested with special equipment that tests a material's tension and compression range. A free body diagram of the applied forces of a static snowboard are shown on the left. |
As a snowboarder leans into the front end of the snowboard
on a hill,
weight is shifted and momentum is increased. A kinetic frictional
force is applied, causing ground heat as well as heat on the
board.
Safety plays a huge role in snowboard design. Although most hazards commonly found in human error, a common hazard found in snowboard design is the layout of the layers. A slight imperfection can cause a snowboard to break if not designed or tested properly. Another imperfection may be the heat tolerance of one of the material exposed at the edge. Should one or more material have an insufficient thermal conductivity, parts of a snowboard may deform and cause injury. Heat, as mentioned earlier, is caused by the frictional force between the snow and the board. It may seem ridiculous to believe that heat may be a hazard since the environment is rather cold.
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Design testing- A snowboard is tested by a Snowboard Engineer on a 30 degree inclined plane. By understanding Newton's second law, knowing the friction coefficient between the polyethylene surface and snow, as well as the mass of the snowboard and the engineer, the engineer can determine his acceleration due to gravity and other forces (air drag being negligible) acting on the snowboard. Obtaining these two calculations can further determine the snowboard's structural strength. |
Suppose the engineer's mass is 70kg, and the snowboard's
mass is 5 kg. A friction coefficient of 0.04 was determined in the
laboratory. To find the acceleration of the snowboarder, we must find
the force driving the snowboarder down the hill. According to the free
body diagram above, the force driving down the snowboarder is indicated by
the vector labeled mgsinθ. But there is also a frictional force
retarding the downward motion, which is defined as μFn, where μ is the
friction coefficient and Fn is the normal force. The normal force Fn
is the force pushing against the snowboarder, which is equal to the force
which the snowboarder applies to the ground perpendicular to the incline.
This force is defined as mgcosθ, therefore the normal force Fn is Fn = mgcosθ = (75kg)(9.81m/s^2)cos30 = 637 N Therefore the frictional force is Ff = μFn = (0.04)(637N) = 25.5 N And the driving force of the snowboarder is Fd = mgsinθ - Ff = (75kg)(9.81m/s^2)sin30 - 25.5N = 440N Finally we can find the acceleration of the snowboarder. Since the engineer insists on keeping the snowboard on the ground, we assume ΣF = ma = mgsinθ - Ff a = (mgsinθ - Ff)/m a = 5.8 m/s^2 |
Image courtesy of snowboarding.com |
The dimensions of a snowboard are specific for every
person's physique and riding ability. In a snowboard/ski shop, you
would probably notice that several snowboards have a 2-3 digit number
printed on the top side (where holes are drilled). This number
usually indicates the effective edge of a snowboard. A person
of a certain height and weight should consider looking at a reference
chart for indicating which effective edge length is ideal. A basic
rule of thumb states that the taller a snowboarder is, the longer that
person's snowboard should be.
The average width and sidecut radius define what sort of riding a person will primarily do with the snowboard. A small sidecut radius (more curved sides) will mean a narrower snowboard, thus allowing better control of turning. Whereas a snowboard with a larger sidecut radius makes room for a wide snowboard, hence more surface area. More surface area will mean more pressure, which leads to a greater potential energy and finally, more speed when traveling. |
Image courtesy of snowboarding.com |
Image courtesy of snowboarding.com
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