On the surface of a certain component made of aluminium with a modulus of elasticity of 75 GPa and a Poisson’s ratio of 0.35, a strain gauge rosette measures the following strains 0 = –94 × 10-6 60 = 370 × 10-6 120 = 235 × 10-6 The aluminium has a yield strength of 95 MPa. a) Determine the strain components x, y, and xy from the strain gauge measurements. b) Determine values for x, y and xy from the strain components in part (a). c) Determine the magnitude of the principal stresses. d) What is factor of safety according to the maximum distortion energy theory of failure? [20 marks] [40 marks] [40 marks] [20 marks]
In: Mechanical Engineering
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Bill, a process engineer, learns from a former classmate who is now a regional compliance officer with the Occupational Safety and Health Administration (OSHA) that there will be an unannounced inspection of Bill’s plant. Bill believes that unsafe practices are often tolerated in the plant, especially in the handling of toxic chemicals. Although there have been small spills, no serious accidents have occurred in the plant during the past few years. What should Bill do? |
In: Mechanical Engineering
Materials are subject to changes from temperature. We know there are several states of matter; solid, liquid, gas, and plasma. However, within a solid-state, materials have their properties affected, in particular, brittleness. The Liberty ships of the Second World War were often breaking from cold weather.
What causes these failures, what materials are affected, and are there any that are not? How is brittleness calculated and measured (types of measurement) and what does this means for aircraft material selection and design considerations? You may include the influence of this problem from a maintenance perspective. Your work, due in Module 3, is to write a report of a minimum of 2,000 words.
In: Mechanical Engineering
An F/A-18F Super Hornet weighing 22,000 kg is flying at Mach 0.7 at an altitude of 3.5 km. The plane has a length of 18.3 m, a wingspan of 13.6 m and a height of 4.9 m. Assume that the shape of the aircraft can be approximated by a flat rectangular plate.
(a) Calculate the thrust force required to maintain level flight and constant speed.
(b) If the pilot suddenly changes pitch to fly straight up, determine whether he will black-out
(experience more than 9g deceleration) due to the manoeuvre.
(c) Estimate whether the plane would have stopped moving in a horizontal direction before an observer at sea-level heard the manoeuvre. (For a bonus of up to 100 marks, mathematically derive the formula for the final velocity in the horizontal direction and calculate the value at the instant the observer at sea level hears the manoeuvre.)
In: Mechanical Engineering
6.Demonstrate the effect of cold work on the yield strength, tensile strength, percent elongation, Rockwell B hardness, and modulus of elasticity of Red Brass for flat products by plotting these quantities as functions of the percent cold work using EXCEL. Use English system data obtained from www.matweb.comfor HXX tempers.
In: Mechanical Engineering
A SCADA system monitors an application through an RTU out in the field. Please list typical RTU hardware that may be encountered.
In: Mechanical Engineering
What were the pros and cons of forming another strategic alliance (i.e., the Mazda-Toyota partnership) to compete in the automotive industry?
In: Mechanical Engineering
You are to manufacture a smart phone case, material selection question below:
Speicfy the details of the EXACT material grade selected for each of the three material variations of the smart phone case; one metal, one polymer and one carbon-fibre composite (specify the resin type).
- What would be the best choice of material for the phone case from the three options?
In: Mechanical Engineering
Draw a sectional diagram of an aircraft wing, showing the structure of the wing and the control surfaces. Then detail the most appropriate materials used for each of the main parts, mentioning at least 2 metals, 1 CFC composite, and 1 sandwich material and expalin why each is used in that application, with reference to the properties required to withstand the forces involved.
In: Mechanical Engineering
1. Select 3 materials that you think are best for the design of a smart phone back plate cover (not protection case) : One Metal, One Polymer and One Carbon Fibre composite.
2. Specify the details of the EXACT material grade selected for each of the three material variations of the smart phone case(specify the resin type).
3. What would be the best choice of material for the phone case from the three options?
In: Mechanical Engineering
Explain the nature of defect in casting process and identify the defects through various NDT techniques.
In: Mechanical Engineering
1. Provide at least three advantages and disadvantages of mask-based process compared to the stereolithography process.
2.Name three solid-based RP processes. Briefly explain fundamentally how each process transforms from a solid to form a part?
In: Mechanical Engineering
Wind Tunnel Experiment:
1. Using the manometer measurements, determine the two speeds with which the wind tunnel was operated. (1 mark)
2. Discuss how changes in Reynolds Number affect the flow separation and provide a source that supports your suggestion. (2 mark)
3. Discuss how the angle which separated flow is achieved varies for each tuft depending on its location and explain why this is occurring.
4. What flow structure can be identified at the tip of the wing and describe how the tufts react differently at this location?
5. Calculate the Static Pressure Coefficient over the wing using the static pressure values provided. (1 Mark)
CFD Analysis:
6. Describe your CFD methodology, meshing considerations and solution setup. Justify the decisions you have made for these parameters using results that you have obtained or by citing suitable references.
7. Determine the lift and drag for the wing at both angles of attack using the CFD model. (1 Mark)
8. Compare the flow fields for both angles of attack, describe and locate the key flow features such as those in the wake region and separation points if they exist.
9. Calculate the Static Pressure Coefficient over the wing and the velocity field in the wake from your CFD results and plot these over the corresponding experimental results provided. (2 Mark)
Discussion and Conclusion:
10. Include a detailed discussion comparing your CFD analysis and results with the wind tunnel results plotted in question 9. Identify any sources of error between the experiment and the CFD and determine how this may have affected the comparison between the two.
11. If you were asked to repeat the CFD analysis, what would you change in the setup of the model to better predict the flow features viewed in the wind tunnel.
| Manometer (off) | Manometer (low) | Manometer (high) | |||||
| Length (mm) | 255 | 330 | 403 | ||||
| Height (mm) | 52.14649322 | 67.48369711 | 82.41190889 | ||||
| Gradient (°) | 11.8 | 11.8 | 11.8 | ||||
| Manometer reading at low speed: | |||||||
| Tuft 1(°) | Tuft 2(°) | Tuft 3(°) | Tuft 4(°) | Tuft 5(°) | |||
| 1 | - | 16.8 | 14.1 | 15.1 | 12 | Trailing end | |
| 2 | - | 18.3 | 16.3 | 17.5 | 14.2 | ||
| 3 | - | 21.2 | 19.2 | 20.2 | 24.7 |
Leading Edge |
|
| 16.3°-Vortex becomes parallel to the wind tunnel | |||||||
| Manometer reading at high speed: | |||||||
| Tuft 1 | Tuft 2 | Tuft 3 | Tuft 4 | Tuft 5 | |||
| 1 | - | 16.6 | 13.7 | 15.2 | 12.1 | Trailing end | |
| 2 | 14.2 | 17.8 | 15.7 | 16.2 | 13.7 | ||
| 3 | - | 22.1 | 16.7 | 19.8 | 22.1 |
Leading Edge |
|
| 9°-Vortex becomes parallel to the wind tunnel | |||||||
In: Mechanical Engineering
3. Design and draw a circuit using the cascade system to operate two cylinders (A and B) which, on the operation of a start valve, produces the sequence A – B + B – A+. The cylinders should park in the positions B – A + when the start switch is in the ‘off’ position.
4. Modify the circuit designed for question 3 to provide an emergency stop which will park both cylinders in the extended position (i.e. A + B +).
5. Modify the circuit designed for question 3 to provide a fail safe. The fail safe should:
(a) act in the event of a reduced pressure at inlet to the group selecting valve
(b) park the cylinders in the retracted position
In: Mechanical Engineering
Design a four-link mechanism when the motions of the input and the output links are governed by a function y = x2 and x varies from 0 to 2 with an interval of 1.
Assume to vary from 50° to 150° and from 80° to 160°.
In: Mechanical Engineering