哈工大材料力学期末考卷

哈工大材料力学期末考卷1

哈工大2007年春季学期 材料力学期中考试试题

Mechanics of Materials Midterm Exam Spring 2007

(NOTE: This midterm exam, 100 marks in total, is worth 25 percent of your final score.) 1. SINGLE CHOICE QUESTIONS: (7 questions, 3 marks each, 21 marks in total) 1-1. After cold-work hardening processing,

which of the following properties of steel will remain approximately the same?

( )

A. modulus of elasticity B. proportional limit C. percent elongation D. percent reduction in area

1-2. On the mechanical properties of cast iron, the following two statements are made: (1). its shear resisting capability is weaker than that of tension resisting;

(2). its compressive strength is higher than its tensile strength. Among them, ( ) A. (1) is true, (2) is false. B. (1) is false, (2) is true. C. (1) is true, (2) is true. D. (1) is false, (2) is false.

1-3. In Fig. 1-3, two prismatic bars are shown, one with a circular cross-section, the other

one with a square cross-section. If both bars are made of the same material and they have the same cross-sectional area, but with different length, when subjected to the same axial force F, their ( ) are NOT the same.

A. axial normal stress s B. axial strain e C. axial elongation Dl D. lateral strain e¢

Fig. 1-3 Fig. 1-4

1-4. In Fig. 1-4, among the three strain gauges bonded to the surface of a circular shaft subjected to torsion, the reading of strain from gauges ( ) will almost be zero. A. 1 and 2 B. 2 and 3 C. 1 and 3 D. 1, 2 and 3

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