Mechanics of Materials(Central South University) 中国大学慕课答案2026完整版100分

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起止时间:2021-03-01到2021-07-12
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1. Introduction Unit Test of Chapter 1

1、 The ability of a member to resist failure under external load is the _ of material.

A: Strength
B: Stiffness
C:Stability
D: Plastic
答案: Strength

2、 The capacity of a member to maintain its original equilibrium state under external load is the .

A:Stiffness
B:Strength
C:Stability
D:Toughness
答案: Stability

3、 The assumption of deformed solids in material mechanics does not include .

A:Continuity hypothesis
B: Uniformity hypothesis
C:Isotropic hypothesis
D: Plane hypothesis
答案: Plane hypothesis

4、 The stress perpendicular to the section is called .

A:Total stress
B:Normal stress
C: Shear stress
D:Principal stress
答案: Normal stress

5、 What is wrong with the following description of internal forces is .

A:An internal force is an additional interaction between parts of an object caused by an external force
B:The internal forces are continuously distributed throughout the cross section
C:The internal force varies with the external force
D:An internal force is an interaction between particles in an object
答案: An internal force is an interaction between particles in an object

6、 When subjected to a pair of forces of equal magnitude, opposite direction, and the line of action coincident with the axis of the member, the deformation of the member is .

A:Stretch or compression
B:Shear
C:Bend
D:Torsion
答案: Stretch or compression

7、 Before deformation, the distance between two points A and B on the tensile sample is 100mm. After deformation, the increment of the distance between two points is mm, so the average linear strain between two points A and B is .

A:

8、 The basic method to study the internal forces of components in material mechanics is .

A:Superposition method
B:Method of section
C:Force method
D:Energy method
答案: Method of section

9、 The figure shows that the triangular thin plate is deformed by external forces. The vertical displacement of the corner at angle B is 0.3mm, but AB and BC remain straight. Given that AC=200mm, the average linear strain along the AB side is mm.

A:
B:
C:
D:
答案:

10、 On the assumption of uniformity, the of a component is assumed to be the same everywhere.

A:Displacement
B:Stress
C: Strain
D: Modulus of elasticity
答案: Modulus of elasticity

2. Axial tension compression and shear Unit Test of Chapter 2

1、 The application conditions of the normal stress equation is .

A:Materials is in Hooke’s law
B:Load within the elastic range
C:The line of action of the axial force passes through the centroid of the section and is perpendicular to the section
D:All above
答案: All above

2、 In the tensile experiment of low-carbon steel, the stage where the stress remains basically the same while the strain increases significantly is called .

A:Elastic region
B:Yielding
C:Strain hardening
D:Necking
答案: Yielding

3、 The maximum shear stress in the rod in tension and compression is 40MPa, then the maximum normal stress in the rod is equal to .

A:80MPa
B:40MPa
C:60MPa
D:56.6MPa
答案: 80MPa

4、 In the illustrated truss structure, three steel rods. Under the condition that other conditions remain unchanged, after replacing rod 3 with aluminum rod, the axial force on rod 1 and rod 2 will be .

A:Decreased
B:Constant
C:Increased
D:unconfirmed
答案: Increased

5、 The force of the rod is shown in the figure. If the cross-sectional areas of the AB and BC sections are 2A and A, and the elastic modulus is E, then the displacement of the section C is .

A:0
B:
C:
D:
答案:

6、 Hook’s law holds within the .

A:Elastic limit
B: Proportional limit
C:Yield limit
D:Strength limit
答案: Proportional limit

7、 According to the stress-strain diagram shown in the figure, it can be judged that the nominal yield limit σ0.2 of the material is equal to MPa.

A:200
B:260
C:300
D:330
答案: 330

8、 Compared with plastic materials, the biggest characteristic of the tensile mechanical properties of brittle materials is .

A:Low intensity
B:Small deformation under the same tension
C:There is almost no plastic deformation before fracture
D:The stress-strain relationship strictly follows Hooke’s law
答案: There is almost no plastic deformation before fracture

9、 The variable cross-section rod is shown in the figure. Given that and , the maximum normal stress in the rod is MPa.

A:80
B:100
C:120
D:150
答案: 150

10、 As shown in the figure, the connector is known: load F = 60kN, plate width b = 80mm, plate thickness δ = 10mm, rivet diameter d = 12mm, allowable stress [σ] = 160MPa, allowable shear stress [τ] = 120MPa , allowable extrusion stress [σbs]= 240MPa, the material of the plate and the rivet is the same, the following statement is correct.

A:The strength of the connector is
B:Shear strength of the rivet is not satisfied
C:The bearing strength of the rivet is not satisfied
D:The tensile strength of the plate is not satisfied
答案: Shear strength of the rivet is not satisfied

3. Torsion Unit Test of Chapter 3

1、 The power of the motor’s rotor shaft is 150kW and the speed is 15.4 r/s. What is the magnitude of the torque moment produced by this axis? ( )

A:93 kN·m
B:1.55 kN·m
C:68.4 kN·m
D:1.14 KNN·m
答案: 1.55 kN·m

2、 is the torsional shear stress formula of the shaft. The shaft with cross section is applicable to this formula。

A:rectangular
B:elliptical
C:circular
D:any shaped
答案: circular

3、 The outer diameter of the hollow circular axis with equal section is D, and the inner diameter is d=D/2, the ends of the shaft are subjected to a torsion couple. The maximum shear stress on its cross section is equal to .