Contents
Preferred Conceptual design. 3
Table of Figures
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
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
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 the output shaft but the axis of the holes are perpendicular to the axis of the holes in the input shaft.
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.
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.
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 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.
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 8: SHaft engineering Drawing
Figure 9: Joint Engineering drawing
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 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.
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 |
Detection |
Net |
Mitigation |
Over load |
Breakage |
Additional 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 |
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. 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.