Engineering components.

        Engineers design and make things. Let’s assume we’re talking about engineering components. These components are made of MATERIALS (metal, plastic, ceramic, composite etc.). The best material from which to make any given component depends on a number of factors (e.g. mechanical, thermal or electrical properties, density, cost, environmental impact etc.) and the process by which the final material is chosen is MATERIALS SELECTION. It is incumbent on engineers to understand how the various mechanical properties are measured and what these properties represent; they may be called upon to design structures/components using predetermined materials such that unacceptable levels of deformation and/or failure will not occur. We demonstrate this procedure with respect to the design of a tensile-test. In the processing/structure/properties/performance scheme, reasons for studying mechanical properties of metals are as follows: Components made of metal alloys that are exposed to external stresses and forces must be processed so as to have appropriate levels of mechanical characteristics (i.e., stiffness, strength, ductility, and toughness). Thus, it is essential that the designer or engineer understand the significance of these properties, and, in addition, develop a sense of perspective as to acceptable magnitudes of property values. Tasks 1 and 2. In tasks 3 and 4, we use a well-established graphical methodology for materials selection based on quantitative measures of performance called PERFORMANCE INDICES. This methodology is the one employed within the CES 2020software - and part of the aim of this assignment is that you become familiar with the use of this software. You will be using it in all 3 years of your degree. 1. Mechanical Properties of Materials (Stress-Strain diagram) Many materials, when in service, are subjected to forces or loads; examples include the aluminium alloy from which an airplane wing is constructed and the steel in an automobile axle. In such situations it is necessary to know the characteristics of the material and to design the member from which it is made such that any resulting deformation will not be excessive and fracture will not occur. The mechanical behaviour of a material reflects the relationship between its response of deformation to an applied load or force. Key mechanical design properties are stiffness, strength, hardness, ductility, and toughness. TASK 1 (30%) 1.1 Using data provided on the Excel sheet plot force / displacement graph for each metal. 1.2 Using the data and formula provided, calculate stress and strain and plot stressstrain diagram for each metal. Stress σ = F / A σ is the engineering stress in (MPa) F is the force in (KN) A is the cross sectional area of the sample = πd²/ 4 Strain Ɛ = (lf – l0) / l0 Ɛ is the engineering strain (no unit) l0 is the original length of the sample in (mm) lf is the final length of the sample in (mm) 1.3 Show the yield, UTS and breaking stress on the diagram for each metal. 1.4 Calculate young’s modulus for each metal. 1.5 Calculate % Elongation and % Reduction in area for each metal. % EL = (lf – l0) / l0 % RA = (A0 – Af) / A0 1.6 Explain and compare metals behaviour in terms of strength, ductility and stiffness. (200 words) 2. Influence of heat treatment on the microstructure and mechanical properties of steels Conventional heat treatment procedures for producing martensitic steels ordinarily involve continuous and rapid cooling of an austenitised specimen in some type of quenching medium, such as water, oil, or air. The optimum properties of a steel that has been quenched and then tempered can be realized only if, during the quenching heat treatment, the specimen has been converted to a high content of martensite; the formation of any pearlite and/or bainite will result in other than the best combination of mechanical characteristics. During the quenching treatment, it is impossible to cool the specimen at a uniform rate throughout—the surface will always cool more rapidly than interior regions. Therefore, the austenite will transform over a range of temperatures, yielding a possible variation of microstructure and properties with position within a specimen. TASK 2 (20%) Using ‘Iron Carbon Equilibrium Diagram’ Figure 1 below, explain the effect of addition of Carbon to Iron in terms of critical temperature lines, microstructure and mechanical properties. Also with the aid of the phase diagram compare the effect of annealing, normalising and water quenching heat treatment processes on the microstructure, strength, hardness and toughness of a 0.4 plain carbon steel. (250 words) Figure 1: Iron Carbon Equilibrium Diagram 3. Materials and Manufacturing Process Selection 3.1 Materials Selection Charts A materials selection chart is a 2-D plot of one material property (or combination of properties) against another. A simple example might be a plot of Young’s Modulus (yaxis) v Density (x-axis). Such a plot can be generated via CES (Figure 1): Figure 2. Young’s Modulus -v- Density Materials Selection Chart. Any given unique material would occupy a single point on the above chart. Because a material such as cast iron or PVC is, in reality, a family of materials, then it occupies a “bubble” or “island” on the chart as indicated in Figure 2 above. TASK 3 (30%) Work individually to research and select the material and manufacturing method of one of the following parts below. Use CES software compare materials that are most suitable for the chosen component and suggest one material and a manufacturing process to build the part from the selected material. Your analysis should be based on the structure/property/processing/ performance and also involve cost-benefit analysis and quality control of such process with sustainability in mind. (300 words) 1. Connecting Rod 2. Jet Engine Gas Turbine Blade 3. Ceramic Cores 4. Electric Socket 5. Drink Bottles 6. Tennis Racket 7. Internal Combustion Engine Block 8. Electric Motors 9. Robot Arm 10. Hip Implant Density (kg/m^3) 10 100 1000 10000 Young's modulus (GPa) 1e-4 0.001 0.01 0.1 1 10 100 1000 Rigid Polymer Foam (MD) Softwood: pine, along grain CFRP, epoxy matrix (isotropic) Polyvinylchloride (tpPVC) Cast iron, gray Young's Modulus v Density (Level 2 Database) Task 4 (20%) Work individually using CES or any other reliable source to research and select the material and manufacturing method of one of the following parts below. Compare materials that are most suitable for the chosen component and suggest one material and a manufacturing process to build the part from the selected material. Your analysis should be based on NHS requirement for the PPEs to avoid Corona virus (COVID-19) contamination and infection. (300 words) NHS requirements for PPE: 1. Masks 2. Overalls 3. Filters 4. Ventilators 5. Gloves 6. other (see guidance) See the Uniforms and work wear: guidance for NHS employers file:///C:/Users/ue0mgr/Desktop/COVID-19/Uniforms-and-Workwear-Guidance-2-April2020%20(1).pdf Harvard Referencing and Citation should be used within the report. For Guidance: http://library.sunderland.ac.uk/find-resources/referencing/ https://my.sunderland.ac.uk/pages/viewpage.action?spaceKey=AQH&title=Program me+Regulations+and+Assessment&preview=/105484811/106738782/Guidance%20f or%20students%20on%20the%20penalty%20for%20exceeding%20the%20limit%20f or%20assessed%20work%20v2.pdf