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asseignment-1-r5kdrx1e-oop12e50.docx RMIT Classification: Trusted RMIT Classification: Trusted — AERO2566 Aerospace Materials Assignment 1 Family Name: Given Name(s): Student #: ALLOWABLE MATERIALS AND INSTRUCTIONS TO CANDIDATES 1. Write your full name and student number on the first page of this paper. 1. Answer all the questions within the provided space. 1. You have until Wednesday 1st of April 12.00 pm to attempt the questions and submit the assignment. Please submit a PDF copy of the assignment. 1. Show all equations and workings. Marks will be deducted for missing or incorrect units. 1. The maximum possible score is 20 marks and this assessment will contribute 20% to the final course mark. Q1: Explain and distinguish the following engineering terms: (a) Stiffness versus modulus of elasticity [1 mark] (b) Engineering stress versus true engineering stress [1 mark] (c) Fracture toughness versus damage tolerance [1 mark] (d) Fatigue life versus fatigue endurance limit [1 mark] Q2:You are an aerospace design engineer building a robotic arm to support astronauts during spacewalks at the International Space Station (ISS). A 3 m-long cable attached to the robotic arm must be able to lift and support an astronaut weighing up to 60 kg without plastically deforming. The maximum allowable strain experienced by the cable must not exceed 0.1%. The gravitational acceleration at the ISS is 80% that on Earth and your design must consider a safety margin 50% greater than the maximum expected load. Two materials are at your disposal; steel and aluminium cables with respective Young’s moduli values of 210 and 70 GPa. (a) If the cable will be strained to the allowable limit at least on one occasion, calculate the minimum diameter required of the steel and the aluminium cable that will be suitable for this application. Show all your workings step-by-step and report your answers in millimetres (mm). [4 marks] (b) The yield strength of steel is twice that of the aluminium cable. If the densities of the steel and aluminium cables were 7.8 and 2.7 g/cm3, respectively, which of these two materials would you select for this application if your objective was to minimise the weight of the ISS. Show how you arrived at your choice with the support of relevant calculations [2 marks] Q3:Imagine that you are an engineer for an aircraft manufacturing company, and you have been asked to design a bulkhead for a mid-sized aircraft. The structural efficiency of aerospace materials is determined by the loading scenario (e.g., tensile, compression or bending) and the design optimization objective. The structural efficiency equations based on the minimization of weight are given below for different loading scenarios. For this task you have available two materials A and B, whose mechanical and physical properties are given in the table below. Material Density Yield strain Yield strength UTS Strain [ kg/ m 3 ] [%] [ N/mm 2 ] [ N/mm 2 ] [%] A 2 , 700 0.59 415 540 20 B 7 , 800 0.43 1,200 1,560 12 Considering the loading stresses experienced by the bulkhead and using the related structural efficiency equation(s), which one of these two materials A or B, would you select if weight minimization was the objective? Justify your answer through detailed workings [4 marks]. Q4:Consider yourself an as the procurement engineer for a major airline. Your company recently placed an order with a major aircraft manufacturer for an all-aluminium aircraft worth $300 million. Your airline intends to operate the aircraft at a frequency of 1 flight per day over a period of 30 years during which the aircraft will be available 90% of the time. The aircraft will consume 50,000 L of fuel per flight with an average projected lifetime fuel cost of $1/L. A sales consultant from the aircraft manufacturer calls you offering their next generation all-carbon composite aircraft with the latest turbine engines that are 20% more efficient. The consultant also states that the all-carbon composite aircraft has an average availability of 95% over the lifetime. However, the all-carbon composite aircraft will be slightly more expensive than your original order. What should be the maximum acceptable price for the all-carbon composite aircraft before it makes no business sense to switch your order from the all-aluminium to this next-generation all-carbon composite aircraft? Show all your workings. [6 marks] School of Engineering/Aerospace Engineering and Aviation April 2020 Page 6 of 6 aero2566-class-test-12019-rrdkouto.pdf School of Engineering/Aerospace Engineering and Aviation March 2019 — AERO2566 Aerospace Materials Class test 1 Family Name: Given Name(s): Student #: ALLOWABLE MATERIALS AND INSTRUCTIONS TO CANDIDATES 1. Write your full name and student number on the first page of this paper. 2. Answer each question within the provided space. 3. Attempt all questions. 4. Show all equations and workings. Marks will be deducted for missing, incorrect units or unlabeled sketches on final answers. 5. The maximum possible score is 15 marks and this assessment will contribute 15% to the final course mark. Page 2 of 6 Q1: Upon graduation, you are employed as an aerospace design engineer and you are tasked with building a robotic arm to support astronauts during spacewalks at the International Space Station (ISS). A cable attached to the robotic arm must be able to lift an astronaut of average weight 80 kg without fail. The length of an unloaded cable is 5 m and under the extreme loading conditions, the cable must not exceed 5.005 m in length. Under no circumstances should the cable be allowed to deform plastically. (a) Given that the gravitational acceleration at the ISS is 10% lower than that on Earth, that the storage space allows for a cable not larger than 5.3 mm in diameter and that a safety factor of 1.5 must be applied, calculate the minimum modulus of elasticity of a material that can be used to manufacture a cable satisfying the above requirements. (5 marks). Page 3 of 6 (b) Available to you for the manufacturing of the cable are two materials as described below: - A steel cable of ultimate tensile strength of 60 MPa, yield strength of 54.6 MPa, and density of 7.8 g/cm3; - A carbon fibre-reinforced polymer composite cable of ultimate tensile strength 0.126 GPa and density of 1800 kg/m3. Considering that the ISS operates in an extreme thermal environment (e.g., -60 to 50ºC) and that minimizing the satellite launch payload is a primary objective, which of these two materials would you select for the cable? You must justify your selection against these two design requirements, showing all workings that support your selection of the cable material (3 marks). Page 4 of 6 Q2: Imagine that you are the principal engineer of a global helicopter rotor blade manufacturing company. Your company wins a tender to design a new light-weight rotor blade. The structural efficiency of aerospace materials is determined by the loading scenario (e.g., tensile, compression or bending) and the design optimization objective. The structural efficiency equations based on the minimization of weight are given below for different loading scenarios. For this task you have available two materials A and B, whose mechanical and physical properties are given in the table below. Considering that the rotor blade may experience more than one type of loading and using the structural efficiency equations relating to potential loading conditions for the rotor blade, which one of these two materials A or B, would you select if weight minimization was the objective? Justify your answer through detailed workings (3 marks). Material Density E - modulus Yield strength UTS Strain [ kg/ m 3 ] [kN/mm 2 ] [ N/mm 2 ] [ N/mm 2 ] [%] A 2 , 700 70 415 540 20 B 7 , 800 210 1,200 1,560 12 Page 5 of 6 Q3: An airline approaches the aerospace design company that you work for with requirements to design and build a mid-size aircraft