About The Bend Test
The Bend Test is designed to allow the user to determine the "flex" of the ski. The "flex" is a number calculated from an equation made up of elasticity and moment inertia. Force, length, and displacement are calculated together to equal elasticity times moment inertia, "flex number".
Force Application
The force application is a linear actuator powered by a 12v right angle motor. Attached to the linear actuator is a load cell. The linear actuator will pull the ski downward and the load cell will measure the tension of the ski. The linear actuator will pull down on the ski until the load cell measures 50lbs of tension. Once the deflection of the ski is measured, the linear actuator releases the ski back to normal position.
Load Cell
The load cell can be used in tension or compression. We are using it for tension against the ski. The load cell will be pulled opposite directions between the linear actuator and the ski. The load cell has a max of 30kg however, we only need to use about 25kg.
Calculations
The "flex number" is calculated from an equation made up of elasticity and moment inertia. Force, length, and displacement are calculated together to equal elasticity times moment inertia, "flex number".
E = Elasticity
I = Moment of Inertia
F = Force
D = Displacement
L = Length
Jig
The four pictures above show the different setups for the flex test. The point of these different assemblies is to test each part of the ski. The common test is the picture in the top left. The bottom two pictures are the same setup just the ski is flipped around to test both ends of the ski. The bottom pictures are also the way the vibration test is set up.