PERC

RES-G2: STRENGTH OF MATERIALS & ENGINEERING MATERIALS

1. Determine the elongation in a helical steel spring composed of 20 turns of 20-mm diameter wire on a mean radius of 90 mm when the spring is supporting a load of 2.5kN. Use G=83 GPa. A. 160mm B. 165mm C. 170mm D. 175mm

2. During loading of materials, distortion happens, if the distortion disappears and the material returns to its original dimension upon removal of load, this material undergoes what?A. elastic strain B. shear strain C. plastic strain D. tensile strain

3. These materials are hard and brittle, insulative to electricity and heat, and very resistant to high temperatures and harsh environments. A. polymers B. metals C. ceramics D. semiconductors

4. What is the mixture of two or more materials, with microstructure where secondary atoms are imbedded in a primary polycrystalline matrix? A. solid solution B. composites C. alloy D. ceramics

5. The weak attraction experienced by most alkali and transition metals when exposed to an external magnetic field is A. ferrimagnetism C. diamagnetismB. paramagnetism D. antiferromagnetism

6. The strong magnetism that occurs in certain ceramic (crystalline) compounds such as ferrite (e.g. MnFe204) and (ZnFe204), spinels (MgAl204) and garnets is known as A. ferrimagnetism C. diamagnetismB. ferromagnetism D. antiferromagnetism

7. A solid solution where the atoms of the solute element share a single common array of atomic sites with the parent material atomsA. interstitial solid solution C. alpha solutionB. substitutional solid solution D. beta solution

8. A rod 50 mm in diameter and 150 mm long is compressed axially by an uniformly distributed load of 250 KN. Find the change in diameter of the rod if E = 200 GPa and v=0.3. A. 9.5 um B. 8.9 um C. 8.2 um D. 7.5 um

9. It is the internal resistance offered by a unit area of the material from which a member from which a member is made to an externally applied load. A. stress B. strain C. moment D. torque

10. A type of line defect consists of an extra row or plane of atoms in the crystal structure.A. edge dislocations C. screw dislocationsB. mixed dislocations D. interstitial defect

11. __________ defects result from impurities in lattice position. A. substitutional B. vacancy C. interstitial D. frenkel

12. The property of materials capable of withstanding cyclic load is normally express in A. ultimate strength C. fatigue strengthB. yield strength D. rapture strength

13. A method in determining the hardness of a material that uses very small diamond indented into surface features using microscope on metallographic specimen. A. Vickers Pyramid scale B. Rockwell scale C. Brinell scale D. Moh’s scale

14. What is the property of materials which says that two objects cannot occupy the same place and at the same time? A. Impenetrability B. hardness C. toughness D. elasticity

15. A steel bar 50 mm in diameter and 2 m long is surrounded by a shell of cast iron 5 mm thick. Compute the load that will compress the bar a total of 1 mm in the length of 2 m. Esteel = 200 GPa, Eiron = GPa. A. 200kN B. 240 kN C. 280 kN D. 320 kN

16. These materials have a large number of non-localized electrons, as an effect are very good conductors of electricity and heat. They are strong yet deformable, and extensively used in structural applications. A. ceramics B. composites C. semiconductors D. metals

17. Materials composed of more than one material type and are designed to display a combination of the best characteristics of each component material. A. polymers B. ceramics C. metals D. composites

18. Among the elements in the periodic table, which group of element are the most electronegative?A. Halogens C. noble gases B. hydrogen group D. alkali earth materials

19. A steel rod 40 mm in diameter and 3 m long is surrounded by a shell of cast iron 6 mm thick. Compute the load that will compress the combined bar a total of 0.95 mm in the length of 2m. For steel E=300GPa, and for cast iron, E=150GPa. A. 151 kN B. 161 kN C. 171 kN D. 181 kN

20. A steel rod 3.5 m long is secured between two walls. If the load on the rod is zero at 30oC, compute the stress when the temperature drops to -30oC. The cross sectional area of the rod is 1200 mm2, α = 11.7 um/(moC), E=200GPa. A. 110 MPa B. 120MPa C. 130MPa D. 140MPa

21. A linear polymer that has the side group alternating regularly on either side of the chain.A. isotactic B. atactic C. syndiotactic D. copolymer

22. A linear polymer that has the side group alternating randomly on either side of the chain.A. isotactic B. atactic C. syndiotactic D. copolymer

23. In the Moh’s scale, which of the following is the hardest mineral, A. topaz B. quartz C. talc D. corundum

24. A crystal imperfection involving a vacancy of pairs of ions of opposite charges.A. frenkel defect C. vacancy B. schottky imperfections D. interstitial defect

25. What crystalline structure has a coordination number of 12?A. body centered cubic C. face-centered cubic B. diamond cubic D. simple cubic

26. What crystalline structure has a packing factor of 0.52?A. body centered cubic C. face-centered cubic B. diamond cubic D. simple cubic

27. It is also known as alpha iron and it can be considered pure iron. A. Pearlite B. Bainite C. Ferrite D. Austenite

28. Also known as gamma phase iron, is a metallic non-magnetic allotrope of iron or a solid solution of iron, with an alloying element.A. Pearlite B. Bainite C. Ferrite D. Austenite

29. A two-phased, lamellar (or layered) structure composed of alternating layers of alpha-ferrite (88 wt%) and cementite (12%) that occurs in some steels and cast irons?A. Pearlite B. Bainite C. Ferrite D. Austenite

30. A type of steel that contains less than 0.83% carbon.

A. hypereutectoid steel B. eutectoid steel C. hypoeutectoid steel D. bainite

31. A cylindrical pressure vessel is fabricated from steel plates which have a thickness of 20mm. The diameter of the pressure vessel is 500mm and its length is 3m. Determine the maximum internal pressure which can be applied if the stress in the steel is limited to 240 MPa. A. 11.2 MPa B. 65.8 MPa C. 45.6 MPa D. 19.12 MPa

32. A material whose atomic arrangement occurs as periodic, repeating structures over large distances. A. crystalline B. polycrystalline C. solid D. amorphous

33. In engineering materials, nickel silver, also known as German silver is an alloy ofA. copper, nickel and zinc C. nickel and chromium B. iron, copper and nickel D. nickel and iron

34. Most important alloy of nickel (28% copper and 67% nickel) that is used because of their high fatigue strength and resistant to corrosion under the action of reducing mineral acids. A. muntz metal B. hypernik C. nichrome D. monel metal

35. A form of alpha-beta brass with about 60% copper, 40% zinc and a trace of ironA. muntz metal B. hypernik C. nichrome D. monel metal

36. What are substance having the small chemical formula but different structure?A. isomers C. copolymers B. isoelectronic D. isostructural substances

37. The description or type of lattice structure formed in metals such as Cobalt is the _______ structure. A. FCC B. BCC C. simple cubic D. HCP

38. Among the elements listed in the periodic table which possesses the least electronegativity property.A. alkali metals C. halogens B. carbon group D. alkali earth metals

39. A process of producing a hard surface in a steel having a sufficiently high carbon content to respond to hardening by a rapid cooling of the surface.A. flame hardening B. carburizing C. cyaniding D. normalizing

40. A mixture of gibbsite and diaspore in which aluminium is derived.A. limanite B. galena C. bauxite D. cassiterite

41. A tank 9 m in diameter, 10 m high is completely filled with water. Determine the minimum thickness of the tank plating if the stress is limited to 60 MPaA. 5.88 mm B. 11.72 mm C. 7.36 mm D. 23.54 mm

42. An elemental solid having a different crystal structure, usually due to the prevailing temperature and pressure. A. amorphous B. polymorph C. crystallite D. allotrope

43. Silicon is how many % by weight of the earth’s crust.A. 46.5 B. 3.5 C. 27.5 D. 8.0

44. Find the required diameter of a steel member if the tensile design load is 7000 pounds. Assume a safety factor of 5 based on an ultimate strength of 80,000 psi. A. 05570 in B. 0.8618 in C. 0.8928 in D. 0.6180 in

45. A property of matter that is often used by chemist as an “identification tag” for a substance. A. density B. volume C. mass D. weight

46. The quantity needed to close the circuit around a crystalline dislocation is calledA. a gradient vector C. Burger’s vector B. a unit vector D. a Poynting vector

47. What bonding exists in sodium chloride? A. ionic B. metallic C. covalent D. hydrogen

48. If a steel rod of 50mm diameter and 1m long is constructed at the ends and heated to 200oC from an initial temperature of 20oC, what would be the axial load developed? Take the coefficient of thermal expansion, α=12x10^-6 oC and E=200GPa. A. 959 KN B. 848 KN C.737 KN D. 626 KN

49. Determine the maximum torque that can be applied to a hollow circular steel shaft of 100-mm outside diameter and 70-mm inside diameter without exceeding a shearing stress of 60 MPa or a twist of 0.5 deg/m. Use G=83GPa. A. 4,648 N-m B. 3,742 N-m C. 5,403 N-m D. 6,263 N-m

50. An elevator weighs 1000 pounds and is supported by a 5/16” cable, 1500 feet long. When the elevator carries a 1000 pound load, the cable elongates 8” more. What is the modulus of elasticity of the cable?A. 58.7 x 10^6 psi C. 29.3x 10^6 psi B. 62.3 x 10^6 psi D. 81.7 x 10^6 psi

51. A hollow steel shaft 2540 mm long must transmit torque of 34kN-m. The total angle of twist must not exceed 3 degrees. The maximum shearing stress must not exceed 110

MPa. Find the inside diameter of the shaft that meets these condition. Use G = 83 GPa. A. 129 mm B.92 mm C. 125 mm D.65 mm

52. All of the following ingredients are used as steel alloying ingredients to increase strength, hardness, or toughness except A. carbon B. chromium C. copper D. nickel

53. This metal is alloyed with steel to give it corrosion resistance properties, resulting in “stainless steel.”A. vanadium C. chromium B. molybdenum D. magnesium

54. All of the following are processes used to surface-harden steel exceptA. carburizing C. flame hardeningB. cyaniding D. tempering

55. The linear portion of the stress – strain diagram of steel is known as theA. modulus of elasticity C. irreversible rangeB. plastic range D. elastic range

56. It is a measure of the stiffness of a material determined by the slope of the straight-line portion of the stress – strain portion of the stress – strain curveA. Modulus of Elasticity C. StrainB. Modulus of rigidity D. Stress

57. A ductile material is one that can be stretched, formed, or drawn to a significant degree before fracture. A metal that exhibits a percent elongation greater than ____ % is considered to be ductile.A. 1 B. 2 C. 3 D. 5

58. “Modulus of Resilience” isA. the same as modulus of elasticityB. a measure of a materials ability to store strain energyC. the reciprocal of the modulus of elasticityD. a measure of the strain induced in a member

59. Steels can be strengthened by all of the following practices, exceptA. annealing C. grain refinementB. quenching and tempering D. work hardening

60. Corrosion that occurs at grain boundaries under tensile stress. It propagates as stress opens cracks that are subject to corrosion, ultimately weakening the metal until failure.A. localized corrosion C. stress-corrosion crackingB. chloride stress corrosion D. galvanic corrosion

61. In this type of bond, the atoms do not share or exchange electrons to bond together. Instead, many electrons (roughly one for each atom) are more or less free to move throughout the metal, so that each electron can interact with many of the fixed atoms.A. ionic bond C. covalent bondB. metallic bond D. hydrogen

62. Metals containing ________ structures include austensite, aluminum, copper, lead, silver, gold, nickel, platinum, and thorium. These metals possess low strength and high ductility.A. FCC B. BCC C. HCP D. Simple cubic

63. What is the lightest metal available for engineering?A. hydrogen B. magnesium C. aluminum D. silver

64. Aluminum is most widely used in handling food products because of its ____ properties.A. lightweight B. conductive C. non-toxic D. anti-corrosive

65. In strength of materials, the impulse produced in a solid due to sudden change in temp is known as thermal _____.A. fracture B. conductive C. necking D. shock

66. What bonding occurs between a metal and a non-metal having electronegativity difference of 1.8?A. covalent B. polar covalent C. ionic D. metallic

67. Creep belongs to what property of material.A. physical property C. mechanical propertyB. chemical property D. elastic property

68. These are cast iron where the structure is altered by thermal treatments to enhance ductility and tensile strength.A. ductile cast iron C. malleable cast ironB. gray cast iron D. mottled cast iron

69. ________ is a high carbon, iron-carbon-silicon alloy. It is the most common type of cast iron.A. ductile cast iron C. malleable cast ironB. gray cast iron D. mottled cast iron

70. An excessive amount of these element in an alloy of steel will produce “cold shortness” characterized by becoming brittle at room temperature and cannot be cold-worked.A. sulfur B. manganese C. silicon D. phosphorus

71. What refers to the stress in the material at the elastic limit?A. working stress C. ultimate stressB. yield stress D. maximum stress

72. The ratio of shearing stress to shearing strain is called:A. Modulus of elasticity C. Modulus of elongationB. Modulus of rigidity D. Modulus of stressibility

73. It is the ability of a material to absorbed applied energy without failureA. Ductility B. Brittleness C. Hardness D. Toughness

74. What is the phenomenon where all of the applied magnetic field will be excluded from the body of material?A. Hall effect C. SuperconductivityB. Meissner effect D. None of the above

75. Group of dielectric materials that exhibit spontaneous polarization in the absence of an electric fieldA. dielectric C. piezoelectricB. ferroelectric D. pyroelectric

76. Materials that are utilized in transducer devices that convert electrical energy into mechanical strains or vice versaA. dielectric C. piezoelectricB. ferroelectric D. pyroelectric

77. It is the indication of the resistance of a material to indentation by penetrator.A. Ductility C. HardnessB. Brittleness D. Toughness

78. Three-dimensional macroscopic effects are calledA. line defect C. point defectsB. dislocation D. bulk defects

79. It is the atomic migration of that occur along dislocations, grain boundaries and external surfacesA. Flux density C. Diffusion fluxB. Diffusion paths D. None of the above

80. The energy that corresponds to the highest filled state energy at absolute temperatureA. Flux density C. Fermi energyB. Diffusion paths D. thermal energy

81. When applied normal and shear stresses are resolved in such a manner that the shear stresses vanish (go to zero), the resulting normal stresses are called the A. main stresses C. extreme shear stressesB. normal stresses D. principal stresses

82. What are the stresses due to the manufacturing process of the material.A. structural stresses C. residual stressesB. pressure stresses D. thermal stresses

83. This element is used in modern, super strong permanent magnets because of their high coercivitiesA. beryllium B. neodymium C. yttrium D. alnico

84. A phase of uranium metal where it possesses a lattice structure of BCC and expands equally in all directionsA. alpha phase C. gamma phaseB. beta phase D. delta phase

85. The deterioration of an engineered material due to interaction with diverse environments which lead to the degradation of its material properties.A. decay C. oxidationB. corrosion D. dissolution

86. It is defined as a process of joining metal parts by means of a nonferrous filler metal or alloy that melts at a temperature above 800 F, but below that of the metal being joined,A. seaming B. soldering C. brazing D. welding

87. What is the most undesirable of all the elements commonly found in steel?A. sulfur B. phosphorus C. silicon D. manganese

88. What term is used to denote a family of thermosetting polymers that are reaction products of alcohols and acids?A. alkaline B. alkydes C. alcocids D. aldehyde

89. All of the following are crystalline point defects exceptA. Schottky defect C. screw dislocationsB. interstitial impurity defect D. vacancies

90. If the recombination rate of electrons and holes are sufficiently rapid that we do not observe an afterglow we speak ofA. phosphorescence C. fluorescenceB. luminescence D. illuminescence

91. _______ are materials that can become magnetized and be drawn to another magnet but the magnetism only remains if it is in a magnetic field.A. diamagnetic materials C. hard magnetsB. soft magnets D. ferromagnets

92. Which of the following is a natural magnet?A. steel B. dionisia C. magnesia D. lodestone

93. What is the chief ore of the tin?A. Bauxite B. Galena C. Ilmanite D. Cassiterite

94. What is the chief ore of the zinc?A. Ilmanite C. BauxiteB. Cassiterite D. Sphalerite

95. It occurs when a cutting action is applied as you would see with scissors, tin snips or punches.A. Direct shear C. Torsional shearB. Bending stress D. Torsional stress

96. During a stress-strain test, the unit deformation at a stress of MN/m^2 was observed to be 167x10^-6 m/m and at a stress of 140 MN/m^2 it was 667x10^-6 m/m, if the proportional limit was 200 MN/m^2, what is the modulus of elasticity?A. 210 GPa B. 110 GPa C. 170 GPa D. 220 GPa

97. A flanged bolt coupling consists of eight steel 20-mm diameter bolts spaced evenly around a bolt circle 300mm in diameter. Determine the torque capacity of the coupling if the allowable shearing stress in the bolts is 40MN/m^2A. 15.1 kN B. 16 kN C. 14.2 kN D. 13 kN

98. It occurs when a member carries a load perpendicular to its long axis while being supported in a stable manner.A. Direct shear C. Torsional shearB. Bending stress D. Torsional stress

99. The emission of light by a material because of its high temperatures is known asA. Luminescence C. PhosphorescenceB. Incandescence D. Dullness

100. The unit of toughness isA. Joules B. Joules/m2 C. Joules/m D. Joules/m3