2021 材料力学(电子科技大学)1463800455 最新满分章节测试答案

文章目录[隐藏]

Chapter 5： Torsion Test for Chapter 1~ 3 in book
Chapter 7 Transverse Shear Test for Chapters 4 and 5 in book
Stress Transformation (应力转换) 应力转换-课前预习作业
Columns(柱) Quiz for Columns
Combined loads(组合变形) Quiz for Combined loads
Deflections of beams (弯曲变形) Quit for Deflections of beams

本答案对应课程为:点我自动跳转查看
本课程起止时间为:2021-03-22到2021-07-16

Chapter 5： Torsion Test for Chapter 1~ 3 in book

1、问题:The method of sections is used to determine the ( ) acting on the surface of the sectioned body. In general, these resultants consist of a ( ), ( ), ( ), and bending moment.
选项：
A: resultant loadings, force along x, a force along y axis, torsional moment
B:resultant loadings, normal force, shear force, external couple
C:external resultant loadings, normal force, shear force, torsional moment
D:internal resultant loadings, normal force, shear force, torsional moment
答案: 【internal resultant loadings, normal force, shear force, torsional moment】

2、问题:( ) is a measure per unit length of the elongation or contraction of a small line segment in the body, whereas ( ) is a measure of the change in ( ) that occurs between two small line segments that are originally ( ) to one another.
选项：
A:Normal strain, shear strain, angle, perpendicular
B:Shear strain, normal strain, angle, perpendicular
C:Normal strain, shear strain, length, perpendicular
D:Shear strain, normal strain, length, perpendicular
答案: 【Normal strain, shear strain, angle, perpendicular】

3、问题:The rigid beam is supported by a pin at A and wires BD and CE. If the distributed load causes the end C to be displaced 20 mm downward, the normal strain developed in wires DB is ( ) and in wire CE is ( ).
选项：
A:0.00266 mm/mm, 0.001 mm/mm
B: 0.00533 mm/mm, 0.005 mm/mm
C:0.00533 mm/mm, 0.01 mm/mm
D:0.00266 mm/mm, 0.005 mm/mm
答案: 【0.00533 mm/mm, 0.01 mm/mm】

4、问题:A 100-mm long rod has a diameter of 15 mm. If an axial tensile load of 20 kN is applied to it, the change in its diameter is ( ). E = 70 GPa, υ = 0.35.
选项：
A:
B:
C:
D:
答案: 【】

5、问题:If the elongation of wire BC is 0.3 mm after the force P is applied, the magnitude of P is ( ). The wire is A-36 steel and has a diameter of 3 mm.
选项：
A:942 N
B:628 N
C:1256 N
D:314 N
答案: 【942 N】

6、问题:A 20-mm-wide block is firmly bonded to rigid plates at its top and bottom. When the force P is applied the block deforms into the shape shown by the dashed line. The block’s material has shear modulus G = 52 GPa. Assume that the material does not yield and use small angle analysis. The magnitude of P is ( ).
选项：
A:460 kN
B:130 kN
C:260 kN
D:520 kN
答案: 【520 kN】

7、问题:The three suspender bars are made of the same material and have equal cross-sectional areas A. The average normal stress in the bar AB is ( ) if the rigid beam ACE is subjected to the force P.
选项：
A:(7P)/(12A)
B:(5P)/(12A)
C:(2P)/(3A)
D:(P)/(2A)
答案: 【(7P)/(12A)】

8、问题:The solid circular shaft is subjected to an internal torque of T = 8kN·m. The shear stress developed at points A and B are ( ) and ( ), respectively.
选项：
A:79.58 MPa, 59.68 MPa
B:49.7 MPa, 37.3 MPa
C:49700 Pa, 37300 Pa
D:79580 Pa, 59680 Pa
答案: 【79.58 MPa, 59.68 MPa】

9、问题:The shear stress developed at point A on the surface of the shaft is ( ). The shaft has a radius of 60 mm.
选项：
A:11.79 MPa
B:7.42 MPa
C:25.42 MPa
D:30.57 MPa
答案: 【11.79 MPa】

10、问题:A bar AB having length L and axial rigidity EA is fixed at end A. At the other end a small gap of dimension s exists between the end of the bar and a rigid surface. A load P acts on the bar at point C, which is two thirds of the length from the fixed end. If the support reactions at A and B produced by the load P are to be equal in magnitude, the size s of the gap is ( ).
选项：
A:(PL)/(6EA)
B:(2PL)/(3EA)
C:(PL)/(3EA)
D:(2PL)/(EA)
答案: 【(PL)/(6EA)】

11、问题:A circular steel rod of diameter d is subjected to a tensile force P = 3.5 kN. The allowable stresses in tension and shear are 118 MPa and 48 MPa, respectively. The minimum permissible diameter dmin of the rod is ( ).
选项：
A:3.42 mm
B:6.81 mm
C:4.63 mm
D:5.45 mm
答案: 【6.81 mm】

12、问题:When a shaft having a circular cross section is subjected to a torque, the cross section remains plane while radial lines rotate. This causes a ( ) within the material that varies ( ) along any ( ) line.
选项：
A:shear strain; linearly; radial
B:normal strain; linearly; radial
C:shear strain; nonlinearly; radial
D: shear strain; nonlinearly; longitudinal
答案: 【shear strain; linearly; radial】

13、问题:A circular steel tube of length L = 1.0 m is loaded in torsion by torques T. If the inner radius of the tube is r1 = 45 mm and the measured angle of twist between the ends is 0.5°, the shear strain γ1 (in radians) at the inner surface is ( )
选项：
A:
B:
C:
D:
答案: 【】

14、问题:A propeller shaft for a small yacht is made of a solid steel bar 104 mm in diameter. The allowable stress in shear is 48 MPa, and the allowable rate of twist is 2.0° in 3.5 meters. Assuming that the shear modulus of elasticity is G = 80 GPa, the maximum torque Tmax that can be applied to the shaft is ( )
选项：
A:9164 N⸱m
B:4582 N⸱m
C:10602 N⸱m
D:8320 N⸱m
答案: 【9164 N⸱m】

Chapter 7 Transverse Shear Test for Chapters 4 and 5 in book

1、问题: In the case of a beam, a positive shear force acts ( ) against the material and a negative shear force acts ( ) against the material. Also, a positive bending moment ( ) the upper part of the beam and a negative bending moment ( ) the upper part.
选项：
A:clockwise, counterclockwise, compresses, stretches
B:clockwise, counterclockwise, stretches, compresses
C:counterclockwise, clockwise, stretches, compresses
D:counterclockwise, clockwise, compresses, stretches
答案: 【clockwise, counterclockwise, compresses, stretches】

2、问题: At the point of application of a concentrated load, the bend moment ( ) while the rate of change of the bend moment undergoes ( ). At the point of application of a couple, the shear force ( ) while the bending moment ( ).
选项：
A: does not change, an abrupt change, does not change, changes abruptly
B:does not change, no change, changes abruptly, changes abruptly
C:changes abruptly, no change, does not change, changes abruptly
D:does not change, no change, does not change, changes abruptly
答案: 【 does not change, an abrupt change, does not change, changes abruptly 】

3、问题:A beam with an overhang at the left-hand end is shown in the figure. Assume the shear force at the cross section x equal to zero, then the value of x is ( ).
选项：
A:7a/6
B:5a/6
C:6a/5
D:6a/7
答案: 【7a/6】

4、问题:The cross section of a straight beam remains plane when the beam deforms due to bending. This causes ( ) on one side of the beam and ( ) on the other side. The neutral axis is subjected to ( ) .
选项：
A:tensile stress; compressive stress; zero stress
B:compressive stress; tensile stress; maximum normal stress
C:shear stress; normal stress; zero stress
D:normal stress; shear stress; zero stress
答案: 【tensile stress; compressive stress; zero stress】

5、问题:Due to the pure bending deformation, the longitudinal ( ) strain varies ( ) from ( ) at the neutral axis to a maximum at the outer fibers of the beam.
选项：
A:normal; linearly; zero
B:shear; nonlinearly; zero
C:normal; linearly; maximum
D:shear; nonlinearly; zero
答案: 【normal; linearly; zero】

6、问题:For linear-elastic material, the neutral axis passes through the ( ) of the cross-sectional area. This conclusion is based on the fact that the resultant ( ) acting on the cross section must be ( ).
选项：
A:centroid; axial normal force; zero
B:centroid; shear force; zero
C:centroid; bending moment; zero
D:centroid; axial normal force; maximum
答案: 【centroid; axial normal force; zero】

7、问题:In terms of the beams shown in Figs. (a) and (b), their corresponding maximum bending stress are denoted by and , respectively. Thus, is ( ).
选项：
A:1/4
B:1/16
C:1/64
D:4
答案: 【1/4】

8、问题:If the beam is subjected to a bending moment of M = 10 kN⸱m, the bending stress developed at point A is ( ).
选项：
A:3.96 MPa (Tension)
B: 1.98 MPa (Tension)
C:5.94 MPa (Compression)
D:3.96 MPa (Compression)
答案: 【3.96 MPa (Tension) 】

9、问题:If the beam is subjected to a bending moment of M = 16 kN⸱m, the maximum bending stress in the beam is ( ).
选项：
A:59.6 MPa
B:48.6 MPa
C:74.5 MPa
D:85.4 MPa
答案: 【59.6 MPa】

10、问题:Determine the dimension a of a beam having a square cross section in terms of the radius r of a beam with a circular cross section if both beams are subjected to the same internal moment which results in the same maximum bending stress.
选项：
A:a = 1.68r
B:a = 0.68r
C: a = 0.89r
D:a = 1.12r
答案: 【a = 1.68r 】

11、问题:Shear forces in beams cause ( ) shear-strain distributions over the cross-section, causing it to ( ).
选项：
A:nonlinear, warp
B:linear, warp
C:constant, rotate
D: linear, rotate
答案: 【nonlinear, warp】