EGA-214 Supplemental Assessment Design Brief (2018-

2019)

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ContentsIntroduction................................................................................................................................1

Conceptual designs.....................................................................................................................1

Concept 1...............................................................................................................................1

Concept 2...............................................................................................................................2

Concept 3...............................................................................................................................2

Preferred Conceptual design......................................................................................................3

Stress analysis............................................................................................................................3

Engineering Drawings................................................................................................................4

Material and Manufacturing.......................................................................................................5

FMEA.........................................................................................................................................6

Conclusion..................................................................................................................................7

References..................................................................................................................................7

Table of Figures

Figure 1: Concept 1....................................................................................................................2

Figure 2: Concept 2....................................................................................................................3

Figure 3: Concept 3....................................................................................................................3

Figure 4: Shaft stress analysis....................................................................................................5

Figure 5: Joint stress analysis.....................................................................................................5

Figure 6: Shaft factor of safety...................................................................................................5

Figure 7: Joint factor of safety...................................................................................................5

Figure 8: SHaft engineering Drawing........................................................................................6

Figure 9: Joint Engineering drawing..........................................................................................6

Figure 10: Manufacturing selection...........................................................................................7

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Introduction

In this design, three concepts of the universal joint are mentioned and one design among three

is selected based on the simplicity, compactness, manufacturing constraints. All designs can

be made suitable for the given specified requirement. But to make this possible the design

may need more material added or removed. In this project, the design is selected such that the

design must withstand the load requirement and at the same time the design must be able to

perform its function below its endurance limit to achieve the desired life. The design

specifications are given below

The universal joint must be connecting the input and output shaft of diameter 25.4mm

with a thickness of 1.6mm.

The design must withstand the torque of 6Nm and an axial load of 20N.

The design must be able to bend till 45o from the axis of rotation.

The design must be light in weight and cost-effective.

The design is limited to 200 in any direction.

The design must be durable and ensure environmental safety.

Conceptual designs

Concept 1

Figure 1: Concept 1

In this design, both input and the output shaft is connected to a single part joint. Both the

shafts have to be drilled on its sides near to the joint. Same type and size holes are created in

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the output shaft but the axis of the holes are perpendicular to the axis of the holes in the input

shaft.

Concept 2

Figure 2: Concept 2

In this concept, the input and output shafts are connected to a spherical part as in the above

picture. The shafts are connected to a sphere with four extended rodes at its four sides. These

rodes are connected to the input and output shafts.

Concept 3

Figure 3: Concept 3

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The spherical part in the second is removed and the shaft is connected with a ‘C’ bracket to

connect the joint. The connector is a combination of two rodes connected perpendicular but

in the same plane.

Preferred Conceptual design

All the three concepts are capable of withstanding the load and will also have the designed

life cycle. But each design needs the different volume of material added or ejected to make it

best fit for the applications. Since more material increases the material cost, as well as

manufacturing cost the prior factor considered in the selection of the design is the size and

simplicity of the design. Assuming the same materials are using for all designs, and different

other parameters considered for the ranking of the concepts are shown below.

Criteria Weight % Concept 1 Concept 2 Concept 3

Material weight 50 3 1 2

Size 20 3 2 2

Manufacturing 30 3 2 3

Score 3 1.5 2.3

Rank 1 3 2

From the ranking analysis, concept 1 is selected for the universal joint.

Stress analysis

Stress analysis is performed in solidworks2018. Both shaft and the joint is analyzed and the

results are shown below. Both results show that the given material selection and the

dimensions of the shaft are capable of withstanding the loads.

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Figure 4: Shaft stress analysisFigure 5: Joint stress analysis

The static stress analysis shows that the factor of safety obtained for the shaft is 2.7 and the

factor of safety for the joint connecting the shafts is 1.1.

Figure 6: Shaft factor of safety Figure 7: Joint factor of safety

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Engineering Drawings

Figure 8: SHaft engineering Drawing

Figure 9: Joint Engineering drawing

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Material and Manufacturing

The material selected for the universal joint is aluminum 1016 alloy. The material properties

are shown below.

Property Range of values

Density 2500-2900 Kg/M3

Price 2.4-2.6$/Kg

Yield stress 30-500MPa

Melting point 450-650C

Embodied energy 200MJ/Kg

CO2 Footprint 13Kg/Kg

Recycle Possible

The amount of CO2 released per year for the production of aluminum 1016 is 13Kg/Kg. The

total energy used to produce this material is 200MJ/Kg. The selection of material will be the

best fir where the weight is needed to be less. The strength to weight ratio of aluminum 1016

is very height compared to steel.

Figure 10: Manufacturing selection

The above figure shows the different manufacturing process used for making 3D hollow

aluminum or alloys. Four manufacturing process is suitable for the design and shaping of this

material provided a hollow category. All the four manufacturing process are marked based on

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the relative equipment cost as well as relative tooling cost. Out of these manufacturing

process, the less cost is selected and is Sand casting process. This analysis is considered for a

single piece production. When it comes to batch production pressing and sintering

manufacturing method will be considered in the analysis.

FMEA

The importance of failure mode analysis is the make sure the future operations of the design

goes well. Performing this analysis will help to maintain the performance of the design in

time. It also helps to avoid the issues like breakage of the parts due to unexpected load.

Failure

mode

Effects of Failure

Possible

causes of

failure

Severity Probability Detectio

n

Net Mitigation

Over load Breakage Additiona

l load

10 4 4 160 Ensure the

effective load

before

operation

Transverse

loading

Bending more than

allowed

Bending 7 4 5 140 Avoid any

transverse

loading during

operation

Loosening

of parts

Transmission loss

Improper

caring

7 2 8 112 Take

appropriate

care before the

operation and

proper

maintenance

Conclusion

The analysis of the universal joint is performed with the help of the Solidworks software tool.

Suitable design is selected from the three concept design based on the size and weight of the

design. The less weight and size is selected and the material selected is aluminum 1016 alloy.

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The stress developed in the design is less than yield and the factor of safety obtained is 2.2

for the shaft and 1.1 for the connecting part. Failure mode analysis is performed to forecast

the failure may take place due to several changes. Four different manufacturing process is

suitable for this design and the one among four is selected based on the relative tool and

equipment cost. The best manufacturing process suitable for a single piece of the universal

joint is sand casting.

References

Lu, M. (2012). Computer-Aided Design Technology in the Application of Modelling

Design of Shaft Parts. Applied Mechanics and Materials, 246-247, pp.1255-1259.

Bansal, R. (2015). A textbook of the strength of materials. New Delhi: Laxmi

Publications.

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