Human Electric Trike Thesis

Design of an electrically assisted human powered trike

Front Suspension Analysis

Posted by Bob Dold on Friday, October 6, 2006 7:05 PM

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.

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