cage questions for DE car, possible club racer in near future
#92
This is most defiantly not the GR thread. Not that the GR thread was not many hours of guilty entertainment...
If I am reading things right 12Klb load deformed the flat X .8xx and the pyramid X .1xx. If this is true then this simulation would point to the pyramid X being a bit better in a broadside. Granted this is not a large amount of movment but with the pyramid X starting further away from you along with better numbersl. One thing to note it the largest deformation of this pyramid X is right near the drivers side. Might be worth it to build with this tube being thicker than the other 3.
If I am reading things right 12Klb load deformed the flat X .8xx and the pyramid X .1xx. If this is true then this simulation would point to the pyramid X being a bit better in a broadside. Granted this is not a large amount of movment but with the pyramid X starting further away from you along with better numbersl. One thing to note it the largest deformation of this pyramid X is right near the drivers side. Might be worth it to build with this tube being thicker than the other 3.
Last edited by kurt M; 03-21-2006 at 11:48 PM.
#93
Originally Posted by complexx
So the largest deflection is 0.147?
Bro
#94
Originally Posted by kurt M
This is most defiantly not the GR thread. Not that the GR thread was not many hours of guilty entertainment...
If I am reading things right 12Klb load deformed the flat X 7.xx and the pyramid X 1.xx. If this is true then this simulation would point to the pyramid X being quite a bit better in a broadside. One thing to note it the largest deformation of this pyramid X is right near the drivers side. I wonder if there is a way to make this tube section the last one give? If you are building with 1.5X .95 use 1.50X 1.20 for that one tube as an example.
If I am reading things right 12Klb load deformed the flat X 7.xx and the pyramid X 1.xx. If this is true then this simulation would point to the pyramid X being quite a bit better in a broadside. One thing to note it the largest deformation of this pyramid X is right near the drivers side. I wonder if there is a way to make this tube section the last one give? If you are building with 1.5X .95 use 1.50X 1.20 for that one tube as an example.
Good thinking about multiple thickness tubes. Again, I wouldn't put any credence in the absolute numbers as there is a lot of other factors involved in replicating a real crash. I think these numbers are fine, though, for comparison between different designs.
Another note, you will notice that the load is distributed over a fairly large portion of the X. I did this as I didn't know how much of a door typically gets caved in. If you guys want a different loading scenario, please let me know. I'm unemployed right now and have some time to devote to this in between scrambling to find a job and trying to survive. A lot of my time is spent job hunting and related activities on the web, so I will usually be available throughout the day.
Bro
#95
Originally Posted by bruinbro
Yep. I should note that the deflection numbers are for total magnitude, not just in the Z direction. It's a snap to generate a chart with delections in a particular direction, just time consuming to port them into this forum. Do let me know if there is something particular you would like to see.
Bro
Bro
If I had to guess what the thickness of the sheet is, I'd say, maybe .050
#96
Originally Posted by complexx
Would it be possible to runt he analysis with some sheet metal gussets like in some of the pictures previously posted in this thread? A gusset in each of the corners of the center of the X.
If I had to guess what the thickness of the sheet is, I'd say, maybe .050
If I had to guess what the thickness of the sheet is, I'd say, maybe .050
Bro
#98
Gusseted pics
Here's the analysis for the gusseted basic X design. I'm still scratching my head...
Basic model
Broadside crash
Broadside crash side view
Head-on crash point load
Head-on crash distributed load
Thoughts?
Bro
Basic model
Broadside crash
Broadside crash side view
Head-on crash point load
Head-on crash distributed load
Thoughts?
Bro
#99
Very interesting!!
I agree that distributed load is basicly a waste of time. In a front end crash bars from crush zone and suspension pickup points will transfer to points.
One thing I think you might be missing in your model is bottom box beam? (see photo) At least in my 75 911S tub this is a massive if fairly thin walled structure.
I agree that distributed load is basicly a waste of time. In a front end crash bars from crush zone and suspension pickup points will transfer to points.
One thing I think you might be missing in your model is bottom box beam? (see photo) At least in my 75 911S tub this is a massive if fairly thin walled structure.
#100
Originally Posted by kurt M
This is most defiantly not the GR thread.
#101
Was this the flat X? If so there is little change over the non reinforced model. If not then
we got some head scratching for sure. Was this a single plate reinforcment? I wonder what a Taco type install would modle like. I would expect it to move the strain and its result of out to the ends of the tacos. End up with a truncated cone shape.
we got some head scratching for sure. Was this a single plate reinforcment? I wonder what a Taco type install would modle like. I would expect it to move the strain and its result of out to the ends of the tacos. End up with a truncated cone shape.
#102
Originally Posted by bruinbro
Actually, the flat X had a max deflection of 0.817" and the pyramid X had a max deflection of 0.147".
Good thinking about multiple thickness tubes. Again, I wouldn't put any credence in the absolute numbers as there is a lot of other factors involved in replicating a real crash. I think these numbers are fine, though, for comparison between different designs.
Another note, you will notice that the load is distributed over a fairly large portion of the X. I did this as I didn't know how much of a door typically gets caved in. If you guys want a different loading scenario, please let me know. I'm unemployed right now and have some time to devote to this in between scrambling to find a job and trying to survive. A lot of my time is spent job hunting and related activities on the web, so I will usually be available throughout the day.
Bro
Good thinking about multiple thickness tubes. Again, I wouldn't put any credence in the absolute numbers as there is a lot of other factors involved in replicating a real crash. I think these numbers are fine, though, for comparison between different designs.
Another note, you will notice that the load is distributed over a fairly large portion of the X. I did this as I didn't know how much of a door typically gets caved in. If you guys want a different loading scenario, please let me know. I'm unemployed right now and have some time to devote to this in between scrambling to find a job and trying to survive. A lot of my time is spent job hunting and related activities on the web, so I will usually be available throughout the day.
Bro
#103
Try the gusseted X brace, but bend the X brace outward like in one of the previous analysis. I think it was the second one you posted. if your feeling like a special person, you could also try to the same analysis with a .100 gusset. This would be similar to what a taco gusset would do as opposed to a plane sheet gusset.
#104
Interesting indeed.
Part of the reason for the plate can be seen in the stress numbers. All that displacement causes a lot of stress. Could infact yeild things. The plate helps take the load some.
I also agree that to be effective you need to figure in some thing for the car structure. The head on impacts are not realistic since if the impact gets to those forward bars my feet & legs are NOT going to like it anyway. Also the two verticals really should be tied in at the top. That will give the upper points a place to be.
Nice work by the way. Hey just like in the real world once the model is done all the real work begins.
Part of the reason for the plate can be seen in the stress numbers. All that displacement causes a lot of stress. Could infact yeild things. The plate helps take the load some.
I also agree that to be effective you need to figure in some thing for the car structure. The head on impacts are not realistic since if the impact gets to those forward bars my feet & legs are NOT going to like it anyway. Also the two verticals really should be tied in at the top. That will give the upper points a place to be.
Nice work by the way. Hey just like in the real world once the model is done all the real work begins.
#105
Originally Posted by bruinbro
Here's the analysis for the gusseted basic X design. I'm still scratching my head...
Basic model
Broadside crash
Broadside crash side view
Head-on crash point load
Head-on crash distributed load
Thoughts?
Bro
Basic model
Broadside crash
Broadside crash side view
Head-on crash point load
Head-on crash distributed load
Thoughts?
Bro
Perhaps its just the sheet that is deforming to that extent?
Last edited by complexx; 03-22-2006 at 04:58 PM.