Skip to content

I’m using stuff I learned in college

09/30/2011

Who would’ve thought I would be using stuff I learned in college.  This weekend due to my neck being all messed up, I got a chance to work out the math for a possible redesign of the drop in ramp.  Now the issue we were having with the previous ramp was that we lost a lot of speed when we hit the kink.  So I thought there has to be an optimum angle of the drop in ramp where we can maintain the horizontal component of the velocity when exiting.

So with the help of my bf who is a mechanical engineer and drawing up a simple free body diagram to account for most of the forces we can estimate, I was able to get a system of equations to calculate the speed coming off the ramp.  Now I don’t know what the friction of the snowflex is so scouring the internet I found 0.04 and also used 0.1 for waxed ski on snow static as the max coefficient of friction.  I’m going to assume snowflex is within that vicinity.  For the impact force, my assumption is that the steeper the angle, the more impact there will be and hence more energy lost when the rider hits that kink at the bottom.  So after crunching the numbers and actually using MATLAB to code something simple, I was able to get a graph of angle vs speed as well as energy remaining after going across a 4ft box.  Also I have to mention…there was a lot of mistakes I made that I caught.  I did some simple algebra wrong as well as not converting the units…be careful of units when doing something like this.

Here’s a pic of my matlab code


So it seems like depending on the coefficient of friction anywhere from 15 to 25 degrees is optimum.   The less slippery it is, the more slope we need which makes sense, but the steeper the angle the more of the velocity we lose to the vertical component.  Hopefully all works out and it’ll be easy to build the drop in ramp…soon…

Advertisements
No comments yet

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: