Front Suspension Analysis

Today I used CosmosWorks to check the front suspension design, I used the same loading as on the rear swing arm; 3G up, 2G aft, and a 1G lateral load. G is equal to the loading on each front wheel, which comes to 125#. A solid tetrahedral mesh was used on the a-arms, spindle and pushrod with a total node count of 79,560 and 43,415 elements. The stress plot below shows fairly low stresses except for the lower rod end which is around 50ksi. The rod ends are steel so this is an acceptable stress for them.

 

The displacement plot below shows a deflection at the spindle of about .040in, which is acceptable. However, it also shows a large deflection of the pushrod of up to .080″ which indicates it may have buckling problems.

To check the buckling I modeled the push rod by itself and applied the axial load it is seeing of 530# at the 3G, 2G, 1G case. The results of this analysis show a buckling factor of below 1 (.53), indicating there is a problem. I plan on rerunning the analysis using a steel pushrod to see if can withstand the load without bucking, my other alternative is to go with a larger diameter aluminum pushrod.

10/6 Update

Received Garmin Edge 305 yesterday, charged it up and used it in my car on my trip to work this morning. The speed seemed to be accurate to my car’s speedometer within a MPH, I logged the entire ride and was able to plot out the time vs. speed, grade, and elevation. The default sample rate was about once every 3 or 4 seconds, it can be set to sample every second which I will set it for when doing the test runs. See below:

The steepest grade on my way to work was about 15%, right at the start of the ride. I also found a program (G7ToWin) that lets me export the raw data to Excel so I can combine it with the Omega voltage logger data when I receive it.

The 305 also let you export your path to a Google map, as seen below:

Also went ahead and ordered 3 Odyssey PC925 motorcycle batteries from BatteryWeb for $98.88 each, these will be wired together in series to form a 36V, 27 amp-hour pack weighing 78 pounds.

Big Blue Saw emailed me and said they would be delivering the waterjet parts next week, so I should be able to start assembly next weekend.