|
|
|
|
 Engineer Needed (and not the train kind)...
#1029482
06/01/11 09:49 PM
|
Joined: Aug 2008
Posts: 530
OP
Rock Warrior
|
I'm designing a trailer, and need some help understanding the math. If anyone knows how to do beam theory-style math, would you please contact me.
Thanks,
Dave
HUMMER .25: No need to compensate.
1989 Dodge Raider: 3.0/5
1992 Chrysler LeBaron Convertible: 3.0/A
1994 GMC Safari: 4.3/A
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: WagonMaster]
#1029483
06/01/11 10:47 PM
|
Joined: Jan 2011
Posts: 95
Getting the Wheeling Fever
|
|
Oscar
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: WagonMaster]
#1029484
06/01/11 11:11 PM
|
Joined: Jan 2000
Posts: 16,227
Web Wheeler
|
I can't answer those questions but perhaps this can help?
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: off-roader]
#1029485
06/01/11 11:55 PM
|
Joined: Jan 2001
Posts: 13,649
Web Wheeler
|
The bending moment and shear forces vary along the beam length and are often represented diagramatically.
These internal forces may vary along the length of the beam and are usually represented as separate bending moment and shear force diagrams.
The calculation of bending moments and shear forces is traditionally part of structural analysis and is beyond the scope of this unit.
Don't know how mathy you are, but this can get real hairy. There should already be some free trailer plans out there with all the engineering already done. I seen to remember something called finite element analysis that used a Kray or something to do the number crunching, but that was a while ago. Probably do it on your phone now...
Not responsible for advice not taken...
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: fasteddy]
#1029486
06/02/11 02:07 AM
|
Joined: Aug 2008
Posts: 530
OP
Rock Warrior
|
Alas, not mathy at all.
The big question right now is that a trailer parts supplier tells me that a drop axle significantly increases the effective axle overhang past the spring perch. Unfortunately, he doesn't know enough to be able to explain it. As I plan to use a drop, I figure that the actual math would be a good thing to know.
HUMMER .25: No need to compensate.
1989 Dodge Raider: 3.0/5
1992 Chrysler LeBaron Convertible: 3.0/A
1994 GMC Safari: 4.3/A
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: perucho]
#1029487
06/02/11 02:09 AM
|
Joined: Aug 2008
Posts: 530
OP
Rock Warrior
|
5,000# (max) drop axle trailer.
Last edited by WagonMaster; 06/02/11 02:09 AM.
HUMMER .25: No need to compensate.
1989 Dodge Raider: 3.0/5
1992 Chrysler LeBaron Convertible: 3.0/A
1994 GMC Safari: 4.3/A
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: WagonMaster]
#1029488
06/02/11 05:11 AM
|
Joined: Jan 2001
Posts: 13,649
Web Wheeler
|
No math required, just common sense.
If you have a straight axle, you can put the spring perches anywhere up to the back of the hub, so you can minimize the amount of axle between the wheel and the perch.
If you have a drop axle, you can't put the perches in the bend area of the "drop" of the axle, you have to go inboard to the flat section of the axle to place the perch. Since most of the drop profile's I've seen are a ess-ish shape (two 45ish degree bends), instead of a right angle and a right angle, the distance becomes significant,
Not responsible for advice not taken...
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: fasteddy]
#1029489
06/02/11 06:07 AM
|
Joined: Aug 2008
Posts: 530
OP
Rock Warrior
|
No math required, just common sense.
If you have a straight axle, you can put the spring perches anywhere up to the back of the hub, so you can minimize the amount of axle between the wheel and the perch.
If you have a drop axle, you can't put the perches in the bend area of the "drop" of the axle, you have to go inboard to the flat section of the axle to place the perch. Since most of the drop profile's I've seen are a ess-ish shape (two 45ish degree bends), instead of a right angle and a right angle, the distance becomes significant, This axle... http://www.northerntool.com/shop/tools/product_200330525_200330525...for example, appears to have about a 2" "S" as the drop. On a 72" axle (arbitrarily), would the 2" on a side really make that much difference? This is why I need the math... <img src="/forums/images/graemlins/confused.gif" alt="" />
HUMMER .25: No need to compensate.
1989 Dodge Raider: 3.0/5
1992 Chrysler LeBaron Convertible: 3.0/A
1994 GMC Safari: 4.3/A
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: WagonMaster]
#1029490
06/02/11 04:57 PM
|
Joined: Aug 2008
Posts: 530
OP
Rock Warrior
|
OK, found the answer I needed. WOW! What a difference a few inches makes... <img src="/forums/images/graemlins/scared.gif" alt="" />
HUMMER .25: No need to compensate.
1989 Dodge Raider: 3.0/5
1992 Chrysler LeBaron Convertible: 3.0/A
1994 GMC Safari: 4.3/A
|
|
|
Re: Engineer Needed (and not the train kind)...
[Re: WagonMaster]
#1029491
06/02/11 06:19 PM
|
Joined: Nov 2003
Posts: 5,690
Trail Leader
|
What a difference a few inches makes... <img src="/forums/images/graemlins/scared.gif" alt="" />
1999 Mitsu Montero - Crappy Weather
1992 Isuzu Pickup - Zombie Apocalypse
2008 Saturn Sky Redline - Nice Weather
|
|
|
|
|
|
