Supplemental Assessment Design Brief

Contents

Introduction. 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

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 45^o 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 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

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.

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.

 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.

Engineering Drawings