ABSTRACTOur project report investigates the characteristics or more specifically design of a column on which a signboard is to be installed at the gate of IIT ROORKEE. It is a detailed design report for the column with preliminary calculations, materials selection, solid geometry, stress analysis and cost estimation. In order to design the column we have considered drag force of air on the signboard, weight of the signboard and different materials for making the most optimum design of the column such that it supports the weight of the signboard and the drag force on the signboard due to air. Length of the column (5m), dimensions of the signboard (4m*2m*0.05m) and dead load of the assembly (50kg) is given. For designing the column we have used the data given to calculate the forces on the column. Also, we have used software tools like SOLIDWORKS 2014 EDITION for designing the pole and ANSYS 2015 EDITION for the analysis of the column after application of the calculated forces. Finally we have summarized the conclusions of analysis by using ANSYS which includes the material to be used and the design specifications of the pole.

CONTRIBUTION OF GROUP MEMBERS• SAHIL JINDAL:- Contributed in doing the ANSYS analysis

of the tapered column, hollow column and making of SOLIDWORKS design .

• KSHITIJ TIWARI:-Contributed in doing the ANSYS analysis of solid column and making of SOLIDWORKS design

• MANISH KR. JANGIR:- Contributed in doing the ANSYS analysis of solid column and making of SOLIDWORKS

design.• KSHITIZ GAUR:-Contributed in finding the appropriate

materials for the column and making of SOLIDWORKS design.Everyone contributed equally in making the report and final editing and printing of it.

• INTRODUCTION A Column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. Columns are also used to support structures like signboard, transformers, street lights etc. Columns may be rectangular, circular, or polygonal in shape; they may taper toward the top or be of uniform diameter.Columns are members subjected to combined bending and axial compression. Their behaviour under uniaxial bending, biaxial bending and torsional flexural buckling are discussed in this report. A range of behaviour varying from flexural yielding to torsional flexural or flexural buckling is possible. In this report evaluation of strength of beam-columns is evaluated for various materials using ANSYS. The column may fail by reaching either the ultimate strength of the section (in the case of smaller axial load and shorter members) or by the buckling strength as governed by weak axis buckling or lateral torsional buckling. In slender columns with larger axial compression, either weak axis or lateral torsional buckling would control failure. The steps in the analysis of strength of column are presented in this report.

• SOFTWARE TOOLS USED For the solid geometry development of the column we have used SOLIDWORKS 2014 EDITION. In solidworks we have designed a hollow tapered column with some specifications. Then, we calculated the forces acting on the column due to drag force and weight of the signboard. After

calculation we analyze the column design in ANSYS by feeding the data. Analysis in ANSYS gives us- total deformation, equivalent stress, equivalent elastic strain and safety factor. We repeated this process for three different materials which are generally used for making columns. Finally, we chose that material that has the most optimum combination of safety factor and cost of the material.• ASSUMPTIONS

• The center of mass of the signboard is directly above the column and no external torque is exerted because of it.

• The material of the column is linearly elastic, homogenous and isotropic.

• The base of the tower is cantilevered to the ground.• It is assumed that maximum wind speed is 5m/s

• MATERIAL SELECTION We have done the analysis in ANSYS for three different materials which are:-

• ALUMINIUM ALLOY ( Al 7075 ) Properties:- 1. Strength comparable to many steels 2. Strong 3. Good fatigue strength

4. Average machinabilityComposition:- 5.6-6.1% zinc, 2.1-2.5% magnesium, 1.2-1.6% copper, less than 0.5% Si, Fe, Mn, Ti, Cr.

• DUCTILE IRON Properties:-

1. Ductile 2. Fatigue resistance 3. HardComposition:- 3.2-3.6% carbon, 2.2-2.8% silicon, 0.1-0.5% manganese, 0.03-0.05% magnesium, 0.005-0.04% phosphorous, 0.005-0.02% sulphur, less than 0.4% copper, Iron -balance.

• ALUMINIUM ALLOY ( Al 6061-T6 (SS) ) Properties:- 1. Strong 2. Ductile 3. Good fatigue strengthComposition:- 0.4-0.8% Si, 0.2-0.7% Fe, 0.15-0.4% Cu, 0-0.15% Mn, 0.8-1.2% Mg, 0.04-0.35% Cr, 0-0.25% Zn, 0-0.15% Ti, 95.85-98.56% Al

Applied Forces(fixed for all 3 materials)

• On the top of surface area F1= Weight of signboard =490.5N (Along Y-axis)

• Drag force on sign board =1812.6N (Along X-axis)• Weight of pole act at the centre of mass of the pole.• Fixed at the bottom.

• SELECTION OF DESIGN OF THE COLUMN We have selected three column designs for analysis which are-

• Solid bar• Hollow uniform column• Tapered uniform column

• SOLID GEOMETRY DEVELOPMENT We have made the solidworks model of all the three designs. For solid geometry development we used SOLIDWORKS 2014 version.

• HOLLOW COLUMN We have made the solidworks model of hollow column with certain specifications as follows:-

ANSYS ANALYSIS RESULT

Finally, by applying the forces due to drag we analyze the hollow column design in ANSYS.

•

Stress Analysis•

Strain Analysis

• Deformation analysis

• Factor of Safety

• SOLID COLUMN We have made the solidworks model of

solid column with certain specifications as follows:-

ANSYS ANALYSIS RESULTFinally, by applying the forces of drag due to air and weight of the column we analyze the design of solid column.

•

Stress Analysis•

Strain Analysis

• Deformation analysis

•Factor of safety

• HOLLOW TAPERED COLUMN We have made the solidworks model of solid column with certain specifications as follows:-

ANSYS ANALYSIS RESULTFinally, by applying the forces of drag due to air and weight of the column we analyze the design of solid column.

• Stress Analysis

• Strain Analysis

• Total Deformation analysis

• Factor of safety INFERENCE: - So we infer that tapered column is most optimum design because FOS of it lies in the range 3-4 (3.3367) while the FOS of the hollow column is less (2.8904) and that of solid column is more (5.8205) which unnecessarily increases the cost.

ANSYS ANALYSIS RESULTS1. For Al-7075 alloy:-(a).Stress calculations:-Stress type: equivalent (Von-Misses) stress- - Maximum stress=7.4257e7 Pa - Minimum stress=1.1606e5 Pa

We know the Yield strength for Al-7075 alloy: Y=50.5e7 PaSo maximum applied stress is less then yield strength.

Stress distribution-

(b).Equivalent elastic strain:-Maximum elastic strain=0.00037204Minimum elastic strain=6.380e-7

Strain distribution-

(c).Total DeformationMaximum deformation=0.053281 m

As deformation occurs, internal inter-molecular forces arise that oppose the applied force. If the applied force is not too great these forces may be sufficient to completely resist the applied force and allow the object to assume a new equilibrium state and to return to its original state when the load is removed. A larger applied force may lead to a permanent deformation of the object or even to its structural failure.But we get the max .value of deformation here is .053281 m i.e. too large.

So, the total deformation of the column is in allowable range.

(d). Safety Factor:-Maximum FOS=15Minimum FOS=3.3667(Generally minimum value of factor of safety is taken.)

The value of factor of safety for the optimum design should lies b/w 2-4& and we get the value n=3.3667.

2. For Ductile iron:-(a).Stress calculations:Stress type: equivalent (Von-Misses) stress- Maximum stress=8.0285e7 Pa Minimum stress= 96648PaWe know the Yield strength for Ductile iron alloy:-

Y=55.149e7PaSo maximum applied stress is less then yield strength.Stress distribution-

b).Equivalent elastic strain:-Maximum elastic strain=0.00040224Minimum elastic strain=6.5314e-7

(c).Total DeformationMaximum deformation=0.061185 m

.We get the max .value of deformation here is .061185m i.e. too large.So, the total deformation of the column is in allowable range.

(d). Safety factor:-Maximum FOS=15Minimum FOS=3.3667

Generally minimum value of factor of safety is taken.

3. For Al-6061 T6 (SS) alloy:-(a).Stress calculations:stress type: equivalent (Von-Misses) stress- Maximum stress=8.3076e7 Pa Minimum stress=15016 PaWe know the Yield strength for Al-7075 alloy:- Y=27.5e7 PaSo maximum applied stress is less then yield strength.Stress distribution-

b).Equivalent elastic strain:-Maximum elastic strain=0.00041778Minimum elastic strain=1.0859e-7

(c).Total DeformationMaximum deformation=0.060283 m

We get the max .value of deformation here is .060283 m i.e. too large.So, the total deformation of the column is in allowable range.

(d). Safety factor:-Maximum FOS=15Minimum FOS=3.0093

Generally minimum value of factor of safety is taken.

• PRICE • For Aluminum AL 7560 T6 –

Mass - 44.57 KgCost – 47.575 $

• For Ductile Iron – Mass - 112.62kg Cost - 67.572$

• For Aluminum 6061 T6 - Mass - 42.83kgCost - 102.792$

• CONCLUSION So, in order to choose which material is best for the design of column we choose that material which has the most optimum combination of Factor of Safety and cost for the construction of the column. So, by comparing all the three materials we finally infer that Aluminum alloy Al 7075 is best for the design of our column.

• Factor of safety = 3.3667(Minimum)

• Maximum von-misses stress = 72.46 MPa • Material = Aluminum alloy Al 7075 • Total Cost = 47.575 $

• BIBLIOGRAPHY • www.alibaba.com • www.wikipedia.com • www.youtube.com\Ansys -point-force • http://www.hawkridgesys.com/blog/quality-control-type-mesh-ansys/ • www.quora.com • http://help.ansys.com/2015/English/ansys/cworks/c_Solid_Mesh.htm

• http://help.ansys.com/2014/English/ansys/cworks/ c_Mesh_Control_Parameters.htm• http://www.roymech.co.uk/Useful_Tables/Matter/Costs.html as in 2014