Question 2 (a) Two wide plates are fabricated from a 4340 alloy steel. Each of these...
Fantastic news! We've Found the answer you've been seeking!
Question:
Transcribed Image Text:
Question 2 (a) Two wide plates are fabricated from a 4340 alloy steel. Each of these plates is then subjected to a different heat treatment to yield a different set of mechanical properties. Table Q2(a) lists the temperatures of the heat treatment and their corresponding mechanical properties which resulted. Temperature of heat treatment (C) 260 425 Yield Strength (MPa) 1640 1420 Table Q2(a) Fracture toughness (MPam) 50.0 87.4 (b) (i) (11) For each of these plates, describe (by using numerical calculations) if plane strain condition prevails, given that the thickness of the plates fabricated is 5 mm. (4 marks) Based on the answer in Q2(a)(i), is it possible to determine the critical crack length of a surface flaw for each of these plates? If it is possible. compute its critical crack length by analysing the data given in Table Q2(a). Assume that the design stress level is half of its yield strength and Y = 1.0. (6 marks) (iii) The detection limit of the non-destructive inspection (NDI) equipment used is 3 mm. Explain whether a flaw with the critical crack length is subjected to detection using this NDI equipment. (2 marks) A flat plate of steel, with a crack length of 2.0 mm on its surface, is exposed to cyclic tensile and compression stresses. Prior to its operations, it has been determined that the critical crack length is 0.02 m. The 'm' and 'C' values in the Paris equation are 3 and 1.0 10-12 respectively (where the units for 'A' and 'a' are in MPa and m respectively). Apply the Paris equation to determine the tensile stress applied to yield a fatigue life of 5.4910 cycles. Assume Y=1.0, which is independent of its crack length. (8 marks) (c) A 1015 mm long specimen made from a low carbon-nickel alloy is exposed to a tensile stress of 75 MPa at 430C. Figure Q2(c) plots the stress applied versus the percentage of steady-state creep elongation per 1000 hours. Apply the data in Figure Q2(c) to determine the total elongation due to creep after 10,000 h, given that the instantaneous and primary creep elongations add up to 1.3 mm. Stress (MPa) 120 100 80 60 40 0.001 0.01 0.1 Steady-state creep rate (%/1000h) Figure Q2(c) 1 (5 marks) Question 2 (a) Two wide plates are fabricated from a 4340 alloy steel. Each of these plates is then subjected to a different heat treatment to yield a different set of mechanical properties. Table Q2(a) lists the temperatures of the heat treatment and their corresponding mechanical properties which resulted. Temperature of heat treatment (C) 260 425 Yield Strength (MPa) 1640 1420 Table Q2(a) Fracture toughness (MPam) 50.0 87.4 (b) (i) (11) For each of these plates, describe (by using numerical calculations) if plane strain condition prevails, given that the thickness of the plates fabricated is 5 mm. (4 marks) Based on the answer in Q2(a)(i), is it possible to determine the critical crack length of a surface flaw for each of these plates? If it is possible. compute its critical crack length by analysing the data given in Table Q2(a). Assume that the design stress level is half of its yield strength and Y = 1.0. (6 marks) (iii) The detection limit of the non-destructive inspection (NDI) equipment used is 3 mm. Explain whether a flaw with the critical crack length is subjected to detection using this NDI equipment. (2 marks) A flat plate of steel, with a crack length of 2.0 mm on its surface, is exposed to cyclic tensile and compression stresses. Prior to its operations, it has been determined that the critical crack length is 0.02 m. The 'm' and 'C' values in the Paris equation are 3 and 1.0 10-12 respectively (where the units for 'A' and 'a' are in MPa and m respectively). Apply the Paris equation to determine the tensile stress applied to yield a fatigue life of 5.4910 cycles. Assume Y=1.0, which is independent of its crack length. (8 marks) (c) A 1015 mm long specimen made from a low carbon-nickel alloy is exposed to a tensile stress of 75 MPa at 430C. Figure Q2(c) plots the stress applied versus the percentage of steady-state creep elongation per 1000 hours. Apply the data in Figure Q2(c) to determine the total elongation due to creep after 10,000 h, given that the instantaneous and primary creep elongations add up to 1.3 mm. Stress (MPa) 120 100 80 60 40 0.001 0.01 0.1 Steady-state creep rate (%/1000h) Figure Q2(c) 1 (5 marks)
Expert Answer:
Related Book For
Posted Date:
Students also viewed these mechanical engineering questions
-
Image transcription text Module 5 Discussion A' Instructions: This discussion will be completed in two parts, and will give you an opportunity to reect upon this week's content and to interact with...
-
rewrite/downside Integrity and credibility are the ethics of professional practice that Juan Gomez was lacking in this instance. Juan Gomez lacked integrity because he created a conflict of interest...
-
Maximum likelihood estimates possess the property of functional invariance, which means that if is the MLE of , and h() is any function of , then h() is the MLE of h(). a. Let X Bin(n, p) where n...
-
The diagram below depicts the demand curve for "mini burgers" in a local fast-food market. Use the information in this diagram to answer the questions that follow. a. What is the price elasticity of...
-
Consider the discrete optimization problem The feasible set consists of a finite collection of m points in Rn, and we have one inequality constraint. Dualize the inequality and show that the dual...
-
The current price of a stock is $20. In 1 year, the price will be either $26 or $16. The annual risk-free rate is 5%. Find the price of a call option on the stock that has a strike price of $21 and...
-
In March 2020 you can get a 15-year term mortgage from TwinStar credit union to buy a house with a rate of 3.57% APR (given a credit score between 680 - 740 and a down payment of 20%). The lending...
-
Explain Mutual Funds and ETFS including 1) Why and how each are purchased 2) How each makes their investment selections 3) The performance of each historically (for broad US stock market funds/etfs)....
-
How is the cutoff score computed and what role does it play in modeling?
-
Discuss the limitations imposed by the restrictive assumption placed on the discriminant model.
-
Why is R2 not a good measure of fit in a logit model?
-
Carl Cushman, a college professor, age 58, purchased and moved into a house on August 1, 2016. He used the house continuously until September 1 , 2017, on which date he went abroad for a one-year...
-
Evaluate the strategic approaches to managing the employment relationship.
-
Explain the diamond of national competitive advantage theory. Then explain how the existence of the four (4) favorable conditions does not guarantee that an industry will develop in a given locale....
-
Doorharmony Company makes doorbells. It has a weighted- average cost of capital of 5% and total assets of $ 5,900,000. Doorharmony has current liabilities of $ 750,000. Its operating income for the...
-
Company data for dividend per share (DPS), earnings per share (EPS), share price, and price-to-earnings ratio (P/E) for the most recent five years are presented in Exhibit 10-9. In addition,...
-
The best model to use when valuing a young dividend-paying company that is just entering the growth phase is most likely the: A. Gordon growth model. B. Two-stage dividend discount model. C....
-
In asset-based valuation models, the intrinsic value of a common share of stock is based on the: A. Estimated market value of the companys assets. B. Estimated market value of the companys assets...
Study smarter with the SolutionInn App