Help needed to calculate stress and strain for a frame work?

[side-show-bob]

Hi all

I have been asked to make a frame work that will be 1600 x 1600 x 700mm to take a weight of approx 1.5Tons it has been so long since i have had to work out structural stresses and strains can anyone help me or point me in the right direction?

Cheers

Rob

 

[FranV8]

Well I'll give it a quick go:

Stress (Pa) = Force (N)/Area (m^2)

Strain = New length/original length

Youngs Modulus = Stress/strain

You'd need to include a sketch of your frame and where the loads would act on it. I assume it's to hold a mass in the air off the floor, so predominently the loads are compressive, but if they are off centre, or overhung, there'd be a need to consider moments etc.

Also, loading in all conditions, e.g. if you're leaning on it, when things are being loaded onto it, wind loads if need be etc. etc.

For vertical struts you'd need to look up something like Euler's buckling loads.

Then, knowing the tensile strength of your material, you'd normally design to a fair factor of safety. For some reason, off the top of my head, I think 6 rings a bell for lifting equipment.

Hope this helps as a starter for 5.

 

[Jake]

Box angle pfc. Post a drawing ill put it in to solidworks

 

[^neo^]

100 x 100 x 3 box with a few braces in, won't go anywhere

 

[side-show-bob]

i have been playing with google sketchUp, and this is the result please let me know if you think it will be ok for a uniformed load of for safety lets say 2ton

[/IMG]

Front

[/IMG]

Side

[/IMG]

Top

[/IMG]

 

[^neo^]

Only weak part is the legs where they arent tied in, but would think you could chuck 2t on that without any worries. Tie the legs in and you could probably double that!

 

[side-show-bob]

would you say they require a cross brace half way up or would angle braces like the middle be better?

 

[Delgado]

Personally, depending on how the weight was distrubuted, I'd build it something like this....

 

[^neo^]

Pretty much like ^^^^^^^^ that i'd say, but stick with your 100 x box. Leg ties could be 50, they're only stopping any possible lateral movement bending the legs

 

[stormin]

i have been playing with google sketchUp, and this is the result please let me know if you think it will be ok for a uniformed load of for safety lets say 2ton

[/IMG]

Front

[/IMG]

Side

[/IMG]

Top

[/IMG]

Make all sides like the one labelled "front" ie with the diagonal corner braces and also put a horizontal tie at the foot of the braces. Do you need to get in at the underside? If not a fully braced cube would be the best shape strength wise.

 

[Jake]

results

Stress analysis of Part1

Author: JAKE

Company: NAS AGILITY


Note:
Do not base your design decisions solely on the data presented in this report. Use this information in conjunction with experimental data and practical experience. Field testing is mandatory to validate your final design. Simulation helps you reduce your time-to-market by reducing but not eliminating field tests.

Comments:
DIY MIG
 
Table of Contents
Table of Contents 2
List of Figures 2
Description 3
Assumptions 3
Model Information 3
Study Properties 3
Units 4
Material Properties 4
Loads and Restraints 5
Connector Definitions 5
Contact 6
Mesh Information 6
Sensor Results 6
Reaction Forces 6
Free-Body Forces 6
Bolt Forces 7
Pin Forces 7
Beams 7
Study Results 7
Conclusion 9


List of Figures
Part1-Side-show-bob-Stress-Stress1 8
Part1-Side-show-bob-Displacement-Displacement1 9
Part1-Side-show-bob-Strain-Strain1 9

 

Description

Summarize the FEM analysis on Part1

Comments:
Structural stresses, strains and displacement

Assumptions
Comments:
BOX SECTION RADIUS REMOVE FOR FEA PURPOSES MINIMUM AFFECT TO RESULTS.
ALL JOINTS FULLY WELDED.

Model Information
Document Name Configuration Document Path Date Modified
Part1 Default C:\Users\Sarah\Desktop\test\Part1.sldprt Fri Jul 08 21:00:25 2011

 

Study Properties
Study name Side-show-bob
Analysis type Static
Mesh Type: Solid Mesh
Solver type FFEPlus
Inplane Effect: Off
Soft Spring: Off
Inertial Relief: Off
Thermal Effect: Input Temperature
Zero strain temperature 298.000000
Units Kelvin
Include fluid pressure effects from SolidWorks Flow Simulation Off
Friction: Off
Ignore clearance for surface contact Off
Use Adaptive Method: Off


Units
Unit system: SI
Length/Displacement mm
Temperature Kelvin
Angular velocity rad/s
Stress/Pressure N/mm^2 (MPa)

 

Material Properties
No. Body Name Material Mass Volume
1 SolidBody 1(Boss-Extrude5) [SW]Plain Carbon Steel 143.451 kg 0.0183912 m^3

Material name: [SW]Plain Carbon Steel
Description: Mild steel
Material Model Type: Linear Elastic Isotropic

Property Name Value Units Value Type
Elastic modulus 2.1e+011 N/m^2 Constant
Poisson's ratio 0.28 NA Constant
Shear modulus 7.9e+010 N/m^2 Constant
Mass density 7800 kg/m^3 Constant
Tensile strength 3.9983e+008 N/m^2 Constant
Yield strength 2.2059e+008 N/m^2 Constant
Thermal expansion coefficient 1.3e-005 /Kelvin Constant
Thermal conductivity 43 W/(m.K) Constant
Specific heat 440 J/(kg.K) Constant

 

Loads and Restraints

Fixture
Restraint name Selection set Description
Roller/Slider-1 <Part1> on 4 Face(s)Roller/Sliding
Fixed-1 <Part1> on 4 Face(s) fixed.

Load
Load name Selection set Loading type Description
Force-1 <Part1> on 1 Face(s) apply normal force 20000 N using uniform distribution Sequential Loading

2000KG X 9.81 = 19 620N

Rounded up to 2000 on the safe side.
 


Mesh Information
Mesh Type: Solid Mesh
Mesher Used: Standard mesh
Automatic Transition: Off
Smooth Surface: On
Jacobian Check: 4 Points
Element Size: 43.601 mm
Tolerance: 2.1801 mm
Quality: High
Number of elements: 18746
Number of nodes: 37099
Time to complete mesh(hh;mm;ss): 00:00:26
Computer name: Mega pc




 


Study Results

Default Results

Name Type Min Location Max Location
Stress1 VON: von Mises Stress 0.146134 N/mm^2 (MPa)
Node: 22039 (-798.506 mm,
-450.003 mm,
-642.504 mm) 41.3816 N/mm^2 (MPa)
Node: 34846 (700.025 mm,
-20.0235 mm,
-700.018 mm)
Displacement1 URES: Resultant Displacement 0 mm
Node: 1 (700 mm,
-700 mm,
-700 mm) 0.707986 mm
Node: 3721 (-1.60933e-006 mm,
97 mm,
5.68434e-011 mm)
Strain1 ESTRN: Equivalent Strain 1.32295e-006
Element: 2624 (-798.504 mm,
-474.253 mm,
639.435 mm) 0.000143815
Element: 16257 (700.774 mm,
-10.0237 mm,
-709.1 mm)

Part1-Side-show-bob-Stress-Stress1

Part1-Side-show-bob-Displacement-Displacement1

Part1-Side-show-bob-Strain-Strain1


 

Conclusion
Results indicate steel yield point has not been exceeded
MAX Deflection = 0.7mm Max allowable 4.1mm

 

[side-show-bob]

Thanks for the details, can i ask what program you are using to work it all out?

 

[Jake]

Solidworks 2011 pro, my boss likes us to use fea. Along with cals when theres time on a job, there it a basic program called multi bender which is good for free cals.

 

[side-show-bob]

Solidworks 2011 pro, my boss likes us to use fea. Along with cals when theres time on a job, there it a basic program called multi bender which is good for free cals.

did a quick google search couldnt find multi bender.