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COVENTRY UNIVERSITY

Fea Analysis Of A Shaft And Muff Coupling 305MED Assignment 2

DADAR TARIQ MOHAMED ZAFFAR

11/8/2010

A detailed exploration of finite element analysis using Solidworks simulation and modeling package.


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Content Page No. INTRODUCTION AND OBJECTIVES 2

3D MODELS GENERATION 3

Modeling of the shaft 6

Modeling the shaft key 8

Assembly of parts 9

Assembly of the shaft with the muff and key assembly 10

Simulation of the shaft and coupling in Solidworks Simulation 12

Simulating a cross section of the 15

Discussion 19

Conclusion 22

References 23

Appendix

2D drawings 24


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INTRODUCTION AND OBJECTIVES

My main task was to Design a cast iron solid muff coupling for a mild steel shaft to transmit

40KW at 350 rpm. The allowable shear stress in the key and shaft is not to exceed 45 MPa and

that in the cast iron sleeve is 15 MPa.

Upon completion of the design and assembly of the model, I was required to carry out finite

element analysis to determine the maximum stress, strain and displacement of the model. This

was to be carried out using Solidworks 2010 CAD software.

A detailed report was to be formulated upon completion of the task that will outline:

1. The procedure for creation of the 3D models

2. The order in which the simulation was conducted3. A complete report generated by the package

4. Detailed 2D and 3D drawings of the components

5. A detailed discussion complete with a conclusion.

A detailed 2d drawing was provided which was to be followed while designing the shaft and

muff coupling. Some changes were later made to the drawing in order to facilitate better design

features.

The solid model included the following components.

1. Muff coupling

2. Shaft 1

3. Shaft 2

4. Shaft key

Note:

The procedure provided for the 3D model generation is not a step by step solution and assumes

the reader has some basic understanding of the Solidworks package.


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3D MODELS GENERATION

As mentioned earlier, the models were created using Solidworks. The following is a vbreif

procedure on how to carry out this task. The parts will be modeled in the order shown in the

introduction above.

Modeling the muff coupling

Open Solidworks>new part

1. In the front plane, create a circle and assign a diameter of 63mm.

2. Go to features>extrude and select blind and enter the value 88mm as shown below.

fig 1

3. Select the front face of the extruded part and go to sketch>circle and draw a circle

concentric to the first. Assign a diameter of 25mm.

4. Go to cut extrude and assign a value of 88mm or select through all then select the green

correct symbol to accept.


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fig 2

5. Next we create the key slot which is tapered. To do this, select the Right plane, select

normal to and draw the sketch with the dimensions shown in the figure below.

fig 3


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Modeling of the shaft

1. Go to file>new>part

2. In the front plane create a circle and assign a 25mm dimension.

3. Extrude the sketch to a length of 100 mm as shown below.

fig 7

4. Select any one of the two faces and sketch the slot as shown below.

fig 8

5. Cut extrude the sketch to reveal the slot. Assign a dimension of 60mm to the slot as

shown on the next page.


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fig 9

6. Create a fillet in the slot, do this by selecting the edge inside the slot and select the filletfunction. Assign a dimension of 10mm and accept.

fig 10

7. Create a chamfer around the slotted edge. Apply same procedure as the fillet except thistime select chamfer. Assign a dimension of 2mm as shown below.

8. Finally, go to file>Save asand save the file as shaft in alocation of your choice.


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Modeling the shaft key

1. Go to file>new>part2. In the right plane, draw the sketch as shown below.

fig 11

3. Extrude the sketch and assign a dimension of 8mm as shown below and accept.

4. Finally save your part by clicking file>save as>tapper key.

Now that we have modeled all our parts, we have to assemble them into a single configuration.


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Assembly of parts

Assuming all the parts previously modeled are open in Solidworks, go to file>new>assembly.

In assembly mode, select the assembly tab and select insert components. Select the muff

coupling and the tapper key.

Select the edge of the tapper key and the inner edge of the muff groove. Go to mates in theassembly menu and select coincident as shown above, repeat the same step but this time select

the other edge of the tapper key and the muff coupling.

Do the same with the front edge of the key and the coupling. The final assembly will look asshown below. The edges have been color indicated to highlight the tapered edges.


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Assembly of the shaft with the muff and key assembly

In the assembly menu, select add components and select the shaft, select the circular edge of theshaft which has a slot and the circular edge of the muff, go to mates in the assembly menu andselect concentric as shown below.

This will align the shaft and the muff to be in a horizontal configuration. Next, select the inner

edge of the slot and the lower edge of the key to assemble the shaft into the muff as shownbelow.

Select the parallel mate function. Thiswill align the slot with the key. Nowsimply drag the shaft into the muff toa desired depth. This completes theassembly process for the first shaft.Repeat the same procedure forassembly of the second shaft. To addthe second shaft, go to insertcomponents and select the shaft youselected earlier and repeat theassembly procedure from the rearside of the muff. Finally mate the twofaces of the shafts with each otherand position the shaft in a centralposition.


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The final assembly will look as shown below.

The rendered image of the shaft and coupling looks like the image shown below.

Go to file, save as>assembly in a location of your choice.


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Simulation of the shaft and coupling in Solidworks Simulation

1. Open the assembly and select the simulation option in the assembly menu.2. In the study advisor, select new study.3. In the options window select statics then accept.4. In the fixtures advisor menu, select advanced fixtures.

In the first input box, select the two faces of the shafts, in the second input box, enter thecylindrical faces of the shafts. In the translations sections, select the radial andcircumferential options as shown above and close.


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Defining the loads

In the loads advisor, select torque. In the first input box select the circular face of the muff andfor the second input box, select the same face. Assign a value of 136.418N-m for the torquemagnitude as shown below, accept and exit.

Create a mesh by right clicking the mesh feature on the left side properties window.Move the slider to fine and accept. This will plot the meshed part as shown below.

Finally, select the run option in the simulation menu and wait for the simulation to complete inorder to reveal the plot for stress, strain and displacement.


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Plots

Stress distribution plot

Displacement plot


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Simulating a cross section of the shaft to get accurate results in relation to stress anddisplacement distribution

In one of the faces of the shaft, create a sketch as shown below. Use relative geometry fordimensions. Cut extrude the sketch to get a quadrant of the shaft as shown below.

Under the features tab. Select reference geometry and select axis. Select the two vertices of thequadrant and accept as shown below.

The axis will act as a point of reference during the simulation stage.


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Select new study under the simulation tab. In the fixtures advisor, select advanced fixtures andpick reference geometry. In the window that appears, add the parameters as shown below.

In the second input box, select the axis created earlier, this will be the point of refrence for thetorque distribution.


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Go to the loads advisor and select torque. In both the input boxes, select the face shown below.

Create a mesh using the same procedure outlined previously

Finally, select run from the menu and allow the software to solve the model.


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Plots for stress and displacement distribution

Stress distribution plot

Displacement plot


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Discussion

Solidworks, a very advanced software with exceptionally simplified method of application. Its

friendly graphic user interface coupled with its low level simulation capabilities are ideal forcarrying out simple analysis using the finite element method. It has various features that arehighly adaptable to the current CAD needs. In this task, we were required to design and analyzea muff coupling complete with two shafts and a tapper key. This was successfully completed andis illustrated in great detail above.

The following are the criteria developed as a result of the analysis processes. These data werederived from the softwares report generator.

Analysis data table

Mesh Type: Solid Mesh

Mesher Used: Standard mesh

Automatic Transition: Off

Smooth Surface: On

Jacobian Check: 4 Points

Element Size: 3.4504 mm

Tolerance: 0.17252 mm

Quality: High

Number of elements: 56507

Number of nodes: 81399

Time to complete mesh(hh;mm;ss): 00:00:08

Computer name: 47-PC


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Reaction Forces

Selection set Units Sum X Sum Y Sum Z Resultant

Entire Body N -0.025177 -0.0304642 0.00586468 0.0399542

Free-Body Forces


Entire Body N 0.000932084 0.000517081 -0.000510386 0.0011818

Free-body Moments


Entire Body N-m 0 0 0 1e-033

Nodal solution

Name Type Min Location Max Location

Stress1 VON: vonMises Stress

10737.9N/m^2

Node: 65148

(51.3144 mm,

28.3426 mm,

1.89541 mm)

1.82868e+008N/m^2

Node: 58086

(59.3258 mm,

16.9722 mm,

-96.4534mm)

Displacement1 URES:ResultantDisplacement

0.129518 mm

Node: 68969

(54.5002 mm,

37.6492 mm,

-51.8971mm)

0.139021 mm

Node: 48861

(47.9343 mm,

57.2075 mm,

1.3852 mm)

Strain1 ESTRN:EquivalentStrain

2.61896e-008

Element:47271

(50.5858 mm,

27.5386 mm,

2.16318 mm)

0.0003922

Element:43915

(52.5061 mm,

14.2558 mm,

-95.6386mm)


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Nodal solution for shaft section simulation

Name Type Min Location Max Location

Stress1 VON: vonMises Stress

0.0165402N/mm^2(MPa)

Node: 7809

(0 mm,

0 mm,

50.1362 mm)

22.5132N/mm^2(MPa)

Node: 10640

(-12.4685mm,

0 mm,

3.63607 mm)

Displacement1 URES:ResultantDisplacement

0.13599 mm

Node: 52

(-12.4685mm,

1.30104e-015mm,

0.13599 mm)

0.136354 mm

Node: 61

(-3.59726e-015 mm,

-13.3873 mm,

0.136354mm)

Strain1 ESTRN:EquivalentStrain

1.57878e-007

Element: 513

(-1.48821mm,

-2.52351 mm,

27.5767 mm)

7.63433e-005

Element: 561

(-12.0695mm,

-1.02769 mm,

90.8191 mm)


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Conclusion

Two individual analyses were carried out to find the difference in result. The main objective of this task was to find the stress and displacement in the shaft. Both analysis had different results,but both within the limits of the given range of 15Mpa and 45MPA for the shaft and muff respectively.

The main idea behind carrying out the analysis of a section of the shaft instead of the whole partis to get a detailed view of the stress distribution and to be able to assign restraints in areas thatwould otherwise be inaccessible in whole part.

From the results obtained, it is noticeable that the stress in the shaft originates from the surfacewhere the highest value is noted and reduces towards the core of the shaft.

This is because torque is a surface load and is applied in an angular manner rather than a point

load. It was also noted that the stress was maximum around the pin and the groove. This is due tothe fact that the existence of sharp edges or small isolated surfaces experiences the most pressurein any situation. These points may end up being the points of failure if not addressed during thedesign phase of the shaft.

In summary, Simulation helps you reduce your time-to-market by reducing but not eliminatingfield tests. It is important to verify simulation results with some other form of testing as it is anapproximation mechanism.


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References

1. "SolidWorks." SolidWorks 3D CAD Design Software . Web. 07 Nov. 2010..

2. Solidworks 2010 help feature static analysis


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Appendix

Shaft-Study 2-Stress-Stress1


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Shaft-Study 2-Displacement-Displacement1

Shaft-Study 2-Strain-Strain1


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Assembly-Study 1-Stress-Stress1

Assembly-Study 1-Displacement-Displacement1

Assembly-Study 1-Strain-Strain1


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