Beam Deflection Calculations (BeamBoy) Confirmation Request

Extrusions/Tubing/Hinges/Etc.

Beam Deflection Calculations (BeamBoy) Confirmation Request

Postby yuchan » Sat Mar 05, 2011 10:29 pm

I'm trying to calculate beam deflection for a 34 inch section of the the Misumi HFS5 2020 (I'm just starting with the smallest on my spreadsheet).

I'm having trouble trusting myself because I'm not having a good time finding exact examples to compare against.

Any confirmation would be greatly appreciated :)



Let me go sequentially through my actions:

Start BeamBoy

    A: Enter length of 34 inches.

    B: Enter beam properties:

    1. Moment of inertia for this in the data sheet is 7.42E+03 mm^4
    Convert to in^4 by dividing by 25.4(mm/inch)^4: I get 0.01783 in^4

    2. Modulus of elasticity: I enter in 9 million

    3. Distance to farthest fiber, this is the distance from the neutral plane, so 10mm, which is .39in

    C: Add a simple support at 0 inches and 34 inches.

    D: Add a distributed load for the mass of the aluminum from 0 to 34 inches of .34lb/ft, calculated from (.5 kg/m * 2.2 lbs/kg) / (3.28 ft/m)

    E: Add a point load at 17 inches of 5 lbs.

    F: Click calculate:

I get a maximum deflection of .0286in @ 17 inches.

The same process applied to 34 inches of 2040 with laying flat, I get 17 thousandths. With the 4040, I get 2.8 thousandths.

Does that sound about right? Am I missing anything obvious here or inputting any values wrongly? (distance to farthest fiber, conversions...)


Screen shot 2011-03-05 at 7.28.14 PM.png
Beamboy



UPDATE: Here are more calculations based on the same process:

Type Length D @ 2lbs Deflection @ 5lbs
2020 34 didn't calc 0.02860 in
2040 34 0.00800 in 0.01700 in
2040 48 0.02730 in 0.05000 in
2040 60 0.05890 in 0.10500 in
4040 48 0.00150 in 0.00278 in
4040 60 0.01100 in 0.01800 in






I also tried SolidWork's beam simulator with a distributed 5lb load (because I didn't have a feature I coud put a point load on) and got ~.0033in deflection. :3 I'm sticking with my beamboy calcs, but I'd like to know if I'm doing something wrong there or if it looks good.

Screen shot 2011-03-05 at 6.53.21 PM.png
Solidworks
yuchan
 
Posts: 21
Joined: Mon Aug 30, 2010 5:56 am

Return to Enclosures/Framing Etc.

Who is online

Users browsing this forum: No registered users and 5 guests

cron