LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently December 18, 2018, 11:13 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 419 posts ]  Go to page Previous  1 ... 24, 25, 26, 27, 28
Author Message
PostPosted: July 13, 2016, 10:33 am 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1282
Location: Denver Co
Bobber wrote:
Still planning on the Big Block? What plans are you working from?


Not following here...

also i sent the main and middle tube drawings.

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
PostPosted: July 13, 2016, 1:00 pm 
Offline

Joined: April 15, 2014, 1:54 pm
Posts: 397
Whoops, forgot which car I was working on. But while I'm at it, can I size your chassis for a blown big block Chev? I just happen to have something for you in back.


Top
 Profile  
Reply with quote  
PostPosted: July 13, 2016, 1:06 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1282
Location: Denver Co
Bobber wrote:
Whoops, forgot which car I was working on. But while I'm at it, can I size your chassis for a blown big block Chev? I just happen to have something for you in back.


still not following...

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
PostPosted: July 14, 2016, 11:24 am 
Offline

Joined: April 15, 2014, 1:54 pm
Posts: 397
I haven’t added all the tubes yet, but I wanted to see how much strength this structure gets out of the side rails alone. The side rails don’t do much, less than 1000 ft lb per degree. The problem is that the front and rear "boxes" do not tie the rails together well.

The side rails and roll bar are 2”x0.065” wall tubing. Everything else is 1”x0.065”. Chassis bare weight is at 125 lb.


Attachments:
Twist.jpg
Twist.jpg [ 1020.13 KiB | Viewed 6000 times ]
Top
 Profile  
Reply with quote  
PostPosted: July 14, 2016, 11:49 am 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1282
Location: Denver Co
that looks way off from my cad model which says 205lbs. the main suspension boxes are also 2.0 x.065. There are also a few x braces missing in the rear suspension box.

i sent you an email with the tube sizes.

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
PostPosted: July 14, 2016, 1:52 pm 
Offline

Joined: April 15, 2014, 1:54 pm
Posts: 397
I threw in some more steel to stiffen it up but I still can’t even get up to 1000 ft lb per degree. Bare chassis weight is 145 lb. Is there an analysis by someone else that may indicate why I’m not getting much strength out of this chassis?


Attachments:
Twist 2.jpg
Twist 2.jpg [ 1.7 MiB | Viewed 5992 times ]
Top
 Profile  
Reply with quote  
PostPosted: July 14, 2016, 2:14 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1282
Location: Denver Co
that still looks off. the rear suspension box should be 2" tube. Not sure why it is like that. here is the only other simulation that i have.


Attachments:
2012-10-23_2333.png
2012-10-23_2333.png [ 246.64 KiB | Viewed 5991 times ]

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.
Top
 Profile  
Reply with quote  
PostPosted: July 14, 2016, 3:00 pm 
Offline

Joined: April 15, 2014, 1:54 pm
Posts: 397
Yes, right now I am experimenting with the tubes to see who contributes to the stiffness. I've been analyzing the chassis for pure torsion. Is that what your program is optimizing for? Have you analyzed your side rail framework independent of the end "boxes". I may try that.
Were the end boxes designed for Team 321 suspension?


Top
 Profile  
Reply with quote  
PostPosted: July 14, 2016, 3:08 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1282
Location: Denver Co
Bobber wrote:
Yes, right now I am experimenting with the tubes to see who contributes to the stiffness. I've been analyzing the chassis for pure torsion. Is that what your program is optimizing for? Have you analyzed your side rail framework independent of the end "boxes". I may try that.
Were the end boxes designed for Team 321 suspension?


that was all done for me a long time ago. i think it was optimizing for torsion. My suspension boxes were designed to fit my engine and my own custom suspension. I kind of think this thread was hijacked for its original intent of the lotus chassis. Should we start a new one?

Something has to be way off. It was mentioned before that the At-om chassis has around 4k lbs torsional rigidity so mine should be at least that or better... agree?

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
PostPosted: July 14, 2016, 4:00 pm 
Offline

Joined: April 15, 2014, 1:54 pm
Posts: 397
I agree it might be a good idea to isolate this piece of thread. I'm seeing something I don't understand in the At-om structure and I have to chase that down. Where did the 4000 ft lb number come from?


Top
 Profile  
Reply with quote  
PostPosted: March 14, 2018, 2:58 pm 
Offline

Joined: August 21, 2017, 7:37 am
Posts: 216
Location: Pittsburgh, PA
Im a long time AutoCad user. Downloaded AutoCad Fusion 360 for free a while back to try my luck at CAM failed. Currently trying, and failing, again at load simulations. Got as far as to import my dxf stick fram and assign material but cant for the life of me figure out loads and constraints.

link to STEP file

https://drive.google.com/open?id=1D0v6i ... VLAqfsme2B


Attachments:
fusion 360.JPG
fusion 360.JPG [ 390.66 KiB | Viewed 4646 times ]

_________________
AWD Exotruck 525hp Subaru EJ22 http://www.locostusa.com/forums/viewtopic.php?f=36&t=19011
Top
 Profile  
Reply with quote  
PostPosted: March 16, 2018, 11:47 am 
Offline

Joined: August 21, 2017, 7:37 am
Posts: 216
Location: Pittsburgh, PA
getting warmer. But i keep getting Mesh Errors as i try to add more material

https://youtu.be/9sI0-QUnWV0

_________________
AWD Exotruck 525hp Subaru EJ22 http://www.locostusa.com/forums/viewtopic.php?f=36&t=19011


Top
 Profile  
Reply with quote  
PostPosted: May 21, 2018, 11:46 am 
Offline

Joined: November 26, 2012, 2:29 pm
Posts: 121
Location: Sioux Falls, SD
terryjr wrote:
getting warmer. But i keep getting Mesh Errors as i try to add more material

https://youtu.be/9sI0-QUnWV0

Is there any way you can generate finer mesh for specific areas?

That's how I had to fix a couple problem areas in my model when doing FEA, for some reason my upper outside tubes for the engine bay always gave me issues even though they are designed the same way as everything else. I made it so those two tubes were a finer curve based mesh and everything else is a more simple triangle based and POOF no issues.


Keep in mind this is in Solidworks... I don't know if fusion360 has this capability.

_________________
My build -> viewtopic.php?t=15585


Top
 Profile  
Reply with quote  
PostPosted: July 24, 2018, 12:49 pm 
Offline
User avatar

Joined: December 17, 2010, 1:24 pm
Posts: 1358
Location: Gainesville, Mo.
BUMP!

_________________
Mike - Read my story at http://twinlakesseven.blogspot.com/


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 419 posts ]  Go to page Previous  1 ... 24, 25, 26, 27, 28

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
POWERED_BY