Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: THEend8_
CIVL2110/CIVL9110: Take-Home Final Exam This take-home final exam is to be submitted
before Sunday 6 June 12pm using the CANVAS site for this UoS. This is an INDIVIDUAL assessment task.
As explained previously, the solutions to each problem need to be handwritten (you can either scan the
solutions or use a tablet to write your solutions by hand). You will need to submit a single pdf file with your solutions – the
file should not be longer than 10 pages A4. The file should be named: SID-Exam.pdf There is a total of five problems
and the number of marks attributed for each problem is stated at the start of the problem. The total number
of marks for this exam is 100. Problem 1: (20 marks) You are a part of civil engineering team, that was asked to select
a material for a spherical pressure vessel to be built in refinery. The stress in the vessel wall is t pr 2 = ,
where p is the internal pressure, r the outer radius of the sphere, and t the wall thickness. The mass of the vessel is trm 2 4= ,
where ρ is the material density. The operating stress of the vessel will always be S y , Where S is the safety factor. 1.1)
Show that the minimum mass of the pressure vessel will be y rpSm 3 2= . 1.2) Given the following table,
select the alloy that will produce the lightest vessel. Explain your reasoning and calculations. 1.3) Using the same table,
select the alloy that will produce the minimum cost vessel. Explain your reasoning and calculations.
Alloy σy (MPa) ρ (g/cm3) Cost ($/kg) 1040 carbon steel 600 7.8 0.63 304 stainless steel 205 7.8 3.70 3003-H14 aluminium 145 2.73 3.00 Ti-5 Al- 2.5 Sn (titanium alloy) 827 4.46 15.00 Problem 2: (15 marks) A single crystal of a metal that has the FCC crystal structure is oriented such that a tensile stress is applied parallel to the [110] direction. The critical resolved shear stress for this material is 1.75 MPa. 1) Calculate the magnitude of applied stress necessary to cause slip to occur on the (111) plane in the direction. 2) Calculate the magnitude of applied stress necessary to cause slip to occur on the (111) plane in the direction. 3) Which of these two slip systems is the most favorably oriented (which system will see first plastic deformation)? And why? Problem 3: (25 marks) The mechanical properties of a 4030-carbon steel have been measured in the lab and are as follows: E = 205 GPa; σy = 860 MPa; UTS = 1280 MPa; ν = 0.29. A 22 mm diameter bar of this alloy is used as a structural member in an engineering design. The length of the bar is 2 m. 3.1) The structural load on the bar is the last five digits of your SID in newtons. For example, if your SID is 123456789, the load applied is 56,789N. If the 5th digit of your SID is 0 (eg. 123406789) then replace this 0 by a 1 so the load applied becomes 16,789N. 3.1.1) What will be the length of the bar under this structural load?