Outline Today’s demanding manufacturing environments require
Mar 13,23Question:
Background:
Outline
Today’s demanding manufacturing environments require greater amounts of data to be collected at each stage of the process; through the design phase, manufacturing and logistics – to the products lifecycle. Logistic operations in todays international markets are complex, and tracking parts is essential. Sensors and other data collection devices are key in adapting to Industry 4.0 requirements set out by many companies. The sensor components themselves are not able to operate in certain harsh manufacturing environments and, therefore, require protective cases to minimise damage and maximise their up time.
Many factors need to be considered when designing components with such complex requirements. These include; cost, design life, loads, deflections, dynamic behaviour, material etc. – all of which must be analysed to ensure the safety and reliability – but also ensure. Moreover, as the sensor technology driven sector is rapidly changing, so too are the needs for the required protective equipment; which highlights the need to have efficient design and analysis tool in place to shorten production times.
Objectives and Specifications
The aim of this project is to conduct a finite element based structural analysis of a sensor cover (Figure 1) to ensure it conforms to a set of specifications. The sensor case will house two optical devices, that require sapphire lenses to allow for high transmission of a wide range of wavelengths. As the electronics contained within the case are isolated and sensitive to dimensional change (such as deformations), the maximum deformation of the case cannot exceed 1.00 mm and although a degree of plasticity can be accepted, the final deformation after elastic recovery cannot exceed 0.2 mm. As the sapphire lens cannot withstand excessive deformation without fracturing, the deformation at the location where the lens is mounted (Figure 2) cannot exceed 0.1 mm. Therefore, some modifications to the internal case design and material selection will need to be made. The external shape of the case must remain as-is, and no external dimensional changes are allowed. Tip: supress everything except the case before running an analysis. We are not concerned about the sensors themselves or the lenses – they are just there for your guidance in the redesign.
The sensor cover is floor mounted, therefore, you will need to analyse for a worst-case scenario of the cover being run over by a fork-lift of other heavy loading device. The loads will be applied to the top surface only. The current design of the cover has it mounted via 4 countersunk holes at the edges. In addition, the bottom flanged surface and overlapped edge that runs around the outside are resting against a solid rigid surface. Based on this information, you will need to set-up appropriate boundary conditions within ANSYS and describe in your technical report how these represent the physical setup.
Figure 4 to Figure 6 provide hints on the locations boundary conditions. However, you will need to set these up yourself in ANSYS. Make sure you describe each boundary condition and how it relates to the physical setup in your report, i.e., why certain settings are used within each boundary condition.
Your initial analysis will need to be done with “Structural Steel NL”. You will also need to explore at least three (3) different materials in total, i.e., Structural Steel NL plus 2 others. As you will need to analyse for plastic deformations, make sure you use Non-Linear (NL) materials. Also discuss the type of non-linearity you are using in your model. As the component is in a harsh operating environment, you will need to use metal alloys. Justify the materials you are selecting, discuss them in terms of their properties, cost, manufacturability and anything else you may deem relevant.
You will need to show the effect of mesh sizes. This means you must apply at least two (2) meshing tools of your choice to improve the mesh quality as well as performing a mesh convergence study that plots the max. principle stress as a function of element size in a region of interest. Hint: you may look to simplify your design in SpaceClaim (and justify this simplification) and refine the mesh in certain areas only to create a more efficient analysis. This only needs to be done on the first materials, as one would expect that the mesh you have defined can be used for the proceeding analyses.
The loading conditions are such that only a quarter portion of the cover would be loaded at one time. Therefore, you will need to split the surface to apply the loads, Figure 5. There are 2 forces generated by a vehicle tyre pressing on the surface. The highest load needs to be applied in the Y direction (3250 N) and the smaller load in the X (1750 N) direction (make sure the loads are in the correct direction!). Because you will be looking at the plastic deformations of the cover, make sure you apply the load over three steps. With the first step having zero loads, the second step with the loads applied, and the third and final step zero loads. Use the analysis settings shown in Figure 7 . Include and describe your force convergence plot – use the lecture notes and workshop materials as a reference.
For the post-processing, show and discuss your results in terms of deformations, stresses and strains. Scope the areas that are of interest – for instance, the location where the sapphire lens will mount, and an internal surface where certain stresses may be high. You will need to discuss the post processing results, i.e., Total Deformation, Equivalent Stress, Max. Principle Stress, Equivalent Plastic Strain, in terms of the analysis and material properties.
Now, modify the cover so that you reduce the deformations (elastic and plastic) to those described above, while using the minimal amount of material. Also explore two additional NL materials. Remember the components still need to fit within the cover – so be careful as to where you add or modify the material inside the cover. Compare the original design provided with your modified design – not just the FEA results, but factors that will affect the final outcome like amount of additional material used to strengthen the design and any other influential factors.
Remember, you need to discuss your results, don’t just past in a picture and state the values. Relate them to the physical model.
Technical Report Layout
Before starting your report, please make sure you complete the academic integrity module. Each submitted piece of work will checked for plagiarism, and if your report has been found to breach the academic integrity guidelines, you will be referred to the academic integrity committee for a hearing.
If you are not sure about something relating to academic integrity, please discuss your concerns with the teaching staff as we can guide and help you with any queries before submitting the assignment.
The report can be laid out as follows:
- Use size 12 font for the body text, and format section and titles accordingly.
- Font can be Timed New Roman, Calibri or similar.
- Use spell check and read your assignment before submitting.
- Reference figures and other sources of information. Use a referencing tool such as Zotero https://www.zotero.org/
- Use the numeric IEEE style type.
- MAX 2000 words! Be concise!
To ensure your submission fits the page/word count ranges, make certain to count words in the body using your word processor and then add in the equivalent word counts for your tables and images. References do not count towards the wordcount. Figures and tables are counted by the amount of words they replace. A good rule of thumb is 50 words per image (picture, graph, spectrum, etc.). Figures with two images (e.g. 1A and 1B) are counted as 100 words. Three images amount to 150 words and so on. Brief tables are counted as 100 words each, while longer or wider tables can be up to one full page (200 words). Make sure you include only highly relevant images and remove non-essential images to help your manuscript be more reader-friendly while fitting within the page/word limits.
Answer:
Introduction
SUMMARY
A detailed investigation on the performance of the sensor cover is conducted in this report to ensure its safety and reliability during operation conditions. For this purpose, FEA analysis has been performed on the initial design provided by the professor. The initial design fails to conform to the maximum deformation specified. Therefore, a modification in the design was needed in order to reduce the deformation of the sensor cover due to the loading. The modified design adds some material into it and restricts maximum deformation to the allowed limit. Also, the deformation around the sapphire lens mount area is within limits. Therefore, it ensures its safety during the operating environment. The modified design is also explored with other two materials aluminium alloy and copper alloy.
CONTENTS
- INTRODUCTION
The requirement of sensors and other data collecting devices have become necessary in Industry 4.0. Today, sensors are immensely used in all phases of the process, design, manufacturing and logistics to provide the best technology in the smartest way. But these sensors fail to operate when subjected to harsh operating conditions or unsafe environment [1]. Therefore, their safety must be ensured by providing protective equipment, sensor cover, for continuous running of the process without any interruption. There are many factors involved in designing the sensor cover such as material, cost, design life, deformation, stress induced, etc. These all must to select to optimum level in order to ensure safety and reliability of the system.
The objective of this assignment is to conduct finite element analysis on a sensor cover which houses two optical sensors. The optical devices consist of sapphire lenses for high transmission of a wide range of wavelength. As the optical device and sapphire lenses are sensitive to deformation and critical to failure therefore there safety must be ensure such that no load or very bare minimum load is transferred on these components in operation conditions. For this purpose the deformation in the sensor cover must to restrict to 1 mm. After the elastic recovery the maximum deformation in the cover can be 0.2 mm. Also, the place where the lens is mounted should not deform more than 0.1 mm in order to continue operate without fracture throughout the life. Finite Element Analysis of the sensor cover is conducted in ANSYS v20 for three non-linear materials structural steel, aluminium alloy and copper alloy. The results such as deformation, stress, strains, etc. for all three materials have been discussed and compared. Also, a new design of sensor cover is introduced which conforms to all the set of design requirements.
- FINITE ELEMENT ANALYSIS
- Material
The three materials selected for FEA of sensor cover are Structural Steel, Aluminium Alloy and Copper Alloy. All of them show material non-linearity which means when the loading in the sensor cover exceeds maximum elastic limit, plastic deformation will occur which will restrain the component from coming to original dimension and shape. Therefore, there will be permanent deformation in the sensor cover under extreme loading. The properties of all three materials are shown in the Table1. The structural steel material provides better stiffness and hardness as it has high young’s modulus and therefore less likely to deform or warp [2]. While Aluminium alloy is comparatively lighter, less dense and can provides better manufacturability as it is more malleable and elastic than steel . Also aluminium has better corrosion resisting properties [3]. Lastly copper alloy provides good machinability, corrosion and retention of mechanical properties.
Table1: Material Properties
| Property | Structural Steel NL | Aluminum Alloy NL | Copper Alloy NL |
| Young’s Modulus | 200 GPa | 71 GPa | 110 GPa |
| Poisson’s Ratio | 0.3 | 0.33 | 0.34 |
| Material Density | 7850 kg/m³ | 2770 kg/m³ | 8300 kg/m³ |
| Bulk Modulus | 166.67 GPa | 69.608 GPa | 114.58 GPa |
| Shear Modulus | 76.92 GPa | 26.6692 GPa | 41.045 GPa |
| Yield Strength | 250 MPa | 280 MPa | 280 MPa |
| Tangent Modulus | 1450 MPa | 500 MPa | 1150 MPa |
- Geometry
The sensor assembly consist of the sensor cover, two optical sensors and two sapphire lenses. The complete assembly is shown in fig.1. However, for the FEA analysis only sensor cover is considered and all other parts are suppressed.
- Meshing
The mesh size used is such that there is no significant change in results. For this, a mesh convergence study was performed. To ensure a good quality mesh, Hex dominant method and Face sizing on critical areas are applied. Hex dominant method ensures that there are maximum hexahedron elements in the mesh. The face sizing provides more no. of elements in the area of concerns so that the results evaluated the close to accurate. The mesh convergence study is performed with various mesh size and maximum principal stress is plotted against element size as shown in fig. 3. The final mesh model is shown in fig. 2 with element size of 3mm.
- Boundary Conditions
The sensor cover is floor mounted and fixed to a rigid support at bottom flange surface and overlapped edge that runs around the outside. Four holes are provided in the cover to fix it against the rigid support. The fixed support boundary condition is shown in fig. 4. The load is applied on the top surface of the cover and only on the quarter part of the surface. Therefore, split operation was performed in SpaceClaim on the top surface of the cover to make separate surface where force is applied.
The force is applied in three steps. The first step corresponds to zero loads, step 2 corresponds to loading and final step 3 is for unloading. The force during loading is 3250 N in Y-direction and 1750 N in X-direction. The loading and unloading force graph is shown in fig.5. The green line and red line in force graph corresponds to Y-direction and X-direction force respectively.
- Static Structural Analysis
- Initial Design
Static structural analysis was performed on initial design using structural steel as the material. Various results obtained such as deformation, stress and strain from the analysis are shown here.
The maximum deformation in the sensor cover using initial design is 3.83 mm (Fig.8) during the step 2 i.e. loading and 2.9 mm in step 3 i.e. unloading as shown in fig.9. Therefore there is a permanent deformation of 2.9 in the sensor cover. Also, the maximum deformation at the area of sapphire lens mount as shown in fig.10 is around 0.78 mm which is clearly not acceptable.
Therefore the sensor cover needs to be modifies so that the deformations in the sensor cover conforms to the allowed deformations.
- Modified Design
In the modified design the thickness of the inner shell of the cover in increased by 0.3 mm as shown in fig. 11. This is done in order to provide more material to take the load coming and lesser deformations are expected to be caused. The FEA results of modified design are shown here.
The maximum deformation during loading in the modified design is 0.48 mm (fig.13). The final deformation after elastic recovery comes out to be 0.02 mm (). Also, the maximum deformation occurring near the lens mount area is 0.1 as shown in fig.14. The deformations caused in the modified design are much less as compared to initial design and are under specified limit.
- Other materials
Static structural FEA analysis was also performed on modified design using other materials such as Aluminum alloy and copper alloy. The results of deformation for these materials are shown here.
The modified design with aluminum alloy shows a maximum deformation of 1.29 mm (Fig.15). Also, the maximum deformation around lens mount area is around 0.31 mm (fig.15). In case of copper alloy the maximum deformation is 0.83 mm (Fig.15) and deformation around lens mount area is around 0.2 mm. The modified design using aluminum alloy and copper alloy do not conform to the specified limits for the deflections in the sensor cover which shown greater strength of structural steel to handle load. The aluminum alloy and copper alloy provides manufacturing and corrosion resistance benefits but have lesser strength and ability to resist deformation than structural steel.
- CONCLUSION
FEA analysis on the sensor cover was conducted which gives sufficient idea about its safety and reliability. The initial design fails to satisfy the specified limit for maximum deformation in the cover. The modified design using structural steel conforms to the deformation limit in the sensor cover. The modified design adds some thickness to the cover but provides better strength and resistance to deformation than initial design. Also, the modified design is explored using aluminum alloy and copper alloy. Clearly from the results, structural steel provides greater ability to withstand high loading and resist change in dimension.
- REFRENCES
[1] D. Yu, A. Al-Yafawi, S. Park and S. Chung, “Finite element based fatigue life prediction for electronic components under random vibration loading,” 2010 Proceedings 60th Electronic Components and Technology Conference (ECTC), Las Vegas, NV, 2010, pp. 188-193, doi: 10.1109/ECTC.2010.5490900.
[2] X. Gang, A. Tiancheng, W. Qing and W. Jun, “Simulation Analysis on Mechanical Properties for Corroded Deformed Steel Bar,” 2010 International Conference on Digital Manufacturing & Automation, Changsha, 2010, pp. 350-353, doi: 10.1109/ICDMA.2010.459.
[3] Z. Bao-hong and Z. Zhi-min, “Study on microstructure and mechanical properties of extruded as-cast AZ80 magnesium alloy,” 2011 International Conference on Consumer Electronics, Communications and Networks (CECNet), XianNing, 2011, pp. 3592-3595, doi: 10.1109/CECNET.2011.5768391.
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