Still nothing interesting to report

I have a visit to the Lab Rat Keeper the day before Valentine’s day for a quick blood draw and BP check, and maybe a hamberder or something at one of the several fast food joints in the area. The covfefe house is closed, but despite having a large chunk of the building burned away the Mexican chicken place almost across the street from the office is still serving food. I’ve never been there, it might be a good time to try it out.

On the Sprint-T and Mini Sprint-T front, there has been a minor change in the design around the main cage. Basically the upper frame rail is now running in segments inside the hoops instead of over the corner after I did another stress analysis that showed too much bending stress on the hoop with the rails running outside the bends and the diagonal braces welded to the top and sides through bends and/or bent gussets. What I had before was the rails welded to plate brackets on both sides of the hoops in line with the horizontal and vertical legs of the hoop. What I have now is the rail welded to the top of the hoops right at the end of the bend and also where the diagonal welds to the hoop, kinda sorta. Actually the diagonals have the same size bends as the hoops so the bends line up, and using the same bend to make the connection to the vertical leg as a gusset to carry those loads directly into both legs of the hoop without imposing bending loads that have to be carried through the bend in the hoop. That’s because the bend is the weakest part of the hoop, but by using gussets and routing loads away from the bend it can be made to not fail in a wreck.

On the down side dividing the upper rail into segments and welding it to the top hoop next to the bend slightly reduces the d4 effect for torsional rigidity, because this change moves the top rails about 9″ closer together side-to-side. Instead of being 48″ apart they will be 39″ apart across the top of the cage. That’s a 56% reduction in stiffness in that plane, but that plane only contributes 25% of the overall torsional resistance of the frame. Basically this keeps both of the side planes that resist forces up and down of the total twist vector at the same stiffness, and has no effect on the bottom plane at all so even though that one plane is reduced 56% the total stiffness is only reduced by about 13% total in torsion. Noticeable but not critical. Second downside is the reduction in the access hole in the top of the cage by 4.5″ when it was already barely wide enough to get in and out without twisting sideways. So guess what I get to do getting in and out of the car?

In things that have nothing to do with me or the Sprint-T personally, the squirrel apparently made its escape prior to the arrival of the people we paid almost $400 to remove it. Also Mrs. the Poet has fallen and bruised her backside, enough that she makes involuntary noises about every other step, sometimes very loud noises accompanied by rude words. I’m not so bothered by the rude words as I am the volume used and the frequency. If her butt hurts she needs to lie down and let me take care of her instead of running around complaining I’m not doing anything for her.


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