CIE 110 Materials Past Papers Quiz 1 & 2 - PDF

CIE 110 - Materials Name: Quiz #1 September 13, 2024 ___________________________________________ Checked by: Closed Book; 12 minutes...

CIE 110 - Materials Name: Quiz #1 September 13, 2024 ___________________________________________ Checked by: Closed Book; 12 minutes 1. Of the curves shown on the right, which could be a probability density function? (A or B) 2. (T/F) A probability density function and a cumulative distribution function be used to represent the same distribution? The cumulative distribution plot was prepared to represent the breaking force of a metallic wire. Use the plot to answer questions 3-6. 3. What is the probability that a particular wire sample will break at a force of 1000 lbs or less? 4. What is the probability that a particular wire sample will break at a force greater than l200 lbs? 5. What is the breaking force associated with a 10% probability of breaking? 6. What is the mean of the breaking force? 7. What is the probability that a 100-year storm event will occur this year? page 1 of 2  The histogram shown on the right represents the number of times a paper- Test Group A clip was bent before it broke into two pieces. Use this to answer questions 8 30 30 through 10. 20 20 Count Count 8. Assume no test standard was used to assemble the data. If the tests were repeat- ed using a standard, how is the standard deviation likely to change? (increase, decrease or stay the same) 10 10 0 0 0 5 10 15 20 Cycles to Failure 9. Assuming the sample is normally distributed, what fraction falls between +/- one standard deviation of the mean? 10. What is the correct unit of standard deviation for the data? page 2 of 2 CIE 110 - Materials Quiz #2 Closed Book; 11 minutes 21 September 2022 Please mark your answers on the accompanying answer form. Both answer form and test sheet are to be turned in. NOTE: FOR TRUE/FALSE QUESTIONS: (a) = TRUE, (b) = FALSE For questions 1 to 5 consider the following idealized load-deformation diagram recorded during a tension test of a metallic alloy. The test specimen was 12 in. long and had a square cross-section 0.5 inches on a side. Deformation was measured with a gage that attached to the specimen at points 2 inches apart. We know that the material is elastic up to the yield point, and its constitutive behavior is elastic-plastic. 1. The yield stress is: (a) 32,000 psi 8,000 (b) 28,000 psi rupture (c) 7000 lbs. (d) none of the above yield 6,000 2. The strain at rupture is: Load (a) 0.005 (lbs.) 4,000 (b) 0.02 (c) 0.01 (d) none of the above 2,000 3. The modulus of elasticity is: (a) 40,000 psi 0 (b) 140,000 psi 0.005.010.015.020 (c) 3,200,000 psi Deformation (in.) (d) 11,200,000 psi (e) none of the above 4. The modulus of toughness is closest to: (a) 280 psi (b) 140 psi (c) 35 psi (d) cannot answer based on the information given. 5. If the specimen is loaded up to a deformation immediately prior to rupture and unloaded, the deformation gage reading will be closest to: (a) 0 in. (b) 0.014 in. (c) 0.020 in. (d) cannot answer based on the information given. 64 CHAPTER 3. INTRODUCTION TO MECHANICAL PROPERTIES 6. Of the stress-strain plots shown below, which best represents a plastic material? (a) (b) (c) (d) page 1 of 2 Figure 3.5: Illustration of di↵erent types of constitutive relationships. (a) elastic; (b) inelastic, or plastic; (c) elastic-plastic; (d) elastic-inelastic.  7. Which of the following is not a valid unit of stress? (a) Pascal (b) ft lbs (c) lbs/ft2 (d) psi 8. Carbon ber has a higher elastic modulus than steel ber. If identical specimens of carbon ber and steel ber are subjected to the same stress, which will deform more? (a) the carbon ber (b) the steel ber (c) the two will deform the same amount (d) cannot evaluate from information given 9. Given the materials of the previous problem, if identical specimens of carbon ber and and steel ber are sub- jected to the same strain, which will deform more? (a) the carbon ber (b) the steel ber (c) they will deform the same (d) cannot evaluate from information given 10. Given two materials: A and B. A is stronger than B. Is it possible for B to be tougher than A? (a) Yes (b) No 11. Bonus: (T/F) A stochastic process will always produce the same output for a speci c input. page 2 of 2 fi fi fi fi fi fi fi fi fi fi fi  CIE 110 - Material Quiz # September 24, 202 Name: _____________________________________ Closed Book; 12 minute Please mark your answers on the accompanying answer form. Both answer form and test sheet are to be turned in NOTE: FOR TRUE/FALSE QUESTIONS: (a) = TRUE, (b) = FALS Consider the load-deformation diagram recorded during a tension test of a particular metal alloy. The test specimen was 4 inches long and had a cross-section area of 0.10 in2. Deformation was measured with a gage that attached to the specimen at points 0.5 inches apart. We know the response was elastic up to a measured deformation of 0.005 inches, where plastic deformation began. Use this information to answer questions 1 to 4 1. The ultimate stress is closest to 20,000 (a) 200,000 ps (b) 20,000 ps rupture (c) 36 ks 15,000 (d) 150,000 ps Load (e) 180,000 ps (lbs.) 2. The strain at yield is closest to 10,000 (a) 0.005 in (b) 0.01 5,000 (c) 0.20 (d) 0.002 (e) 0.004 0 0.005.010.015.020 3. The modulus of elasticity is closest to Deformation (in.) (a) 200 MP (b) 3000 lb/i (c) 29,000,000 psi (d) 3,000,000 ps (e) 15,000,000 ps 4. A specimen (same dimensions) of a material with a lower modulus of elasticity is loaded to a deformation of.005 inches. The load in the material is (a) greater than 15,000 lbs (b) less than 15,000 lbs (c) equal to 15,000 lbs (d) cannot be determined from the information given 64 CHAPTER 3. INTRODUCTION TO MECHANICAL PROPERTIES 5. Of the stress-strain plots shown below, which best represents an elastic-plastic material (a) (b) (c) (d) Figure 3.5: Illustration of di↵erent types page 1 of 2 of constitutive relationships. (a) elastic; (b) inelastic, or plastic; (c) elastic-plastic; (d) elastic-inelastic. original shape. As shown in Figure 3.5(c), when an elastic-plastic ma- % 0 i 0 5 2 a. n i i i i i i. 1... s : : s : :. E ?.  6. You need to size a bar that must carry 50,000 pounds. The maximum stress that can be allowed in the material used for the bar is 25,000 psi. What is the minimum required cross-sectional area (a) 0.5 in2 (b) 2.0 in2 (c) depends on the elastic modulu (d) none of the abov 7. (T/F) We have different de nitions of strength because we have different de nitions of failure 8. (T/F) Yield is the onset of elastic deformation 9. (T/F) Materials with high strength always have high toughness 10. (T/F) Hooke’s Law is an example of a constitutive relationship. page 2 of 2 e fi s.. fi ?. CIE 110 - Materials Quiz #2 September 20, 2023 Closed Book; 10 min Please mark your answers on the accompanying answer form. Both answer form and test sheet are to be turned in. NOTE: FOR TRUE/FALSE QUESTIONS: (a) = TRUE, (b) = FALSE A 9 inch-long elastic-plastic alloy specimen with a 0.0625 square inch cross section was tested in a load frame, and the load-deformation plot on the right was recorded. Deformation was measured by a gage with a 2.25 inch gage length. The material is linear-elastic up to yield. Use this information to answer questions 1 to 7. 1. This material may be considered (a) brittle. (b) ductile. 2,000 (c) cannot be determined from the information given. yield 1,500 rupture 2. (T/F) When we refer to the material as being elastic-plastic, Load we are referring to its constitutive relationship. (lbs.) 1,000 3. The stress at yield is: (a) 24,000 psi (b) 2000 psi 500 (c) 1500 psi (d) none of the above 0 0.004.008.012.016 4. The strain at yield is: Deformation (in.) (a).2% (b).00177 (c).004 (d).000444 5. The elastic modulus is closest to: (a) 125,000 psi (b) 375,000 psi (c) 13,500,000 psi (d) 29,000,000 psi 6. If the specimen is loaded up to a deformation immediately prior to rupture and unloaded, what would the de- formation gage most likely read? (a) 0 mm (b) 0.12 mm (c) 0.16 mm (d) none of the above. 7. A second material with a lower elastic modulus but higher yield strength is loaded until the deformation is.004 inches. The load on the material is: (a) less than 1500 lbs. (b) equal to 1500 lbs. (c) greater than 1500 lbs. (d) cannot be determined from the information given. page 1 of 2 8. A 3 meter long rod is subjected to a stress that causes a uniform strain of 0.0004. What is the overall change in bar length due to that stress? (a) 0.0004 (b) 1.2 mm (c) 0.004 m (d) none of the above 9. You are to design a column that is intended to carry 100,000 lbs. The design code says you must use a factor of safety of 1.5 for capacity. If the maximum stress allowed is 1500 psi, what is the cross-sectional area required to meet capacity? (a) 67 in2 (b) 100 in2 (c) 1 ft2 (d) none of the above. page 2 of 2  CIE 110 - Materials Quiz #2 September 25, 2024 Name: _____________________________________ Closed Book; 12 minutes Please mark your answers on the accompanying answer form. Both answer form and test sheet are to be turned in. NOTE: FOR TRUE/FALSE QUESTIONS: (a) = TRUE, (b) = FALSE Two specimens of different elastic-plastic alloys (metals) were tested in a load frame. The measured load- deformation plots are shown below. Both specimens were 60-inch long bars with a 1 inch by 5 inch cross section. Deformation was measured using a 6-inch long gage. Use this information to answer questions 1 to 4. 1. The yield stress of alloy “B” is closest to: (a) 36,000 psi (b) 50,000 psi (c) 70,000 psi (d) 250,000 lbs. (e) 350,000 lbs. 2. The ultimate stress of alloy “A” is closest to: (a) 50,000 psi (b) 70,000 psi (c) 80,000 psi (d) 350,000 lbs. (e) 400,000 lbs. 3. The strain at yield for alloy “B” is closest to: (a) 0.00167 (b) 0.2% (c) 0.01 in. (d) 0.00025 4. Which alloy has a higher modulus of toughness: (a) Alloy “A” (b) Alloy “B”. (c) cannot be determined from the information given. 5. Hooke’s law refers to: (a) A stress-strain response that includes yielding (b) A linear relationship between stress and strain (c) A viscoelastic constitutive relationship 64 CHAPTER 3. INTRODUCTION TO MECHANICAL PROPERTIES 6. Of the stress-strain plots shown below, which best represents an elastic-plastic material? (a) (b) (c) (d) page 1 of 2 Figure 3.5: Illustration of di↵erent types of constitutive relationships. (a) elastic; (b) inelastic, or plastic; (c) elastic-plastic; (d) elastic-inelastic.    7. Titanium has a lower elastic modulus than steel. If identically sized bers of titanium and steel are subjected to the same stress, which will deform more? (a) The titanium ber (b) The steel ber. (c) The two bers will deform the same 8. We are designing a structural column for which the building code requires we use factor of safety of 1.9 in our design. If our maximum expected load is 8,000 lbs, for what load should we design our column? (a) 4,210 lbs (b) 8,000 lbs. (c) 15,200 lbs. (d) 20,400 lbs. 9. A column must support a load of 6,000 lbs. What is the cross sectional area require if the stress is not to exceed 300 psi? (a) 100 square inches (b) 20 square inches (c) 8 square inches (d) 0.5 square inches 10. A stress-strain plot for an elastic-plastic material is shown below. The elastic modulus is closest to: (a) 30 psi (b) 30,000 psi (c) 15,000,000 psi (d) 29,000,000 psi page 2 of 2  fi  fi fi fi