Building mechanics
Review of Architectural Mechanics
Fill in the blanks
1. object balance refers to the object relative to the ground __________ or ________ motion state.
The necessary and sufficient conditions of 2. equilibrium of coplanar force system is _____. Composition of the force of the force system of force polygon ____.
3., a piece of weight 600N, placed on the flat surface, the friction coefficient f=0.3, in the left side of a thrust 150N, the object has a tendency to slide to the right. Fmax=__________, so this piece is in a static state, and the F=__________.
4. in the rigid body as the translation process, the points on the same __________, each instantaneous speed and acceleration of each point is __________.
5.AB bar quality is m, length is L, O1A, O2B quality regardless of the crank, and O1A=O2B=R, O1O2=L, when phi =60 degrees, O1A rod rotate around the O1 axis, the angular velocity Omega is constant, then the instantaneous AB rod should be added to the inertial force is __________ direction for __________.
The 6. pawl ratchet mechanism, excluding the weight of AB, when the system is at equilibrium, A hinge support the pawl constraint force should be ____________ along the line.
The projection along an axis is equal to 7. if the size of a force and the force is the force relationship and shaft is ____________.
Figure 8. will force B to translation, the additional moment of couple size ____________.
The 9. is that the rigid motion velocity projection theorem, the projection of any two points on the speed of the two on the line are ____________.
10. parallel to the plane of a fixed rigid body in plane motion, it took a straight line perpendicular to the plane of the fixed and in ____________.
11. in gear drive, if the rotational speed of the driving wheel
I and the driving wheel II are N1 and N2, then the gear ratio formula of the two gear can be expressed as i12=____________ by its rotation speed.
The 12. point is a physical quantity describing the acceleration ____________ magnitude and direction of change over time.
13. in the international system of units (SI) in length,
____________ and time unit is the basic unit.
A 14. point mass m, with uniform motion velocity along the circle of R radius, the inertial force is ____________.
15. a stiffness coefficient of K spring with one end fixed and
the other end is connected with a particle A, the initial amount of compression spring is delta 1, elongation at the end of 2, the power spring particle A made by this process for
____________.
16. mechanical or structure by ____________, when they transfer motion or load, by force.
17. a thin-walled slender tube, length, diameter D, thickness T, elastic modulus E, Poisson's ratio, when the axial tension of F, the measured circumferential strain line, then change the amount of a d=____________ diameter.
18. practical calculation assumption in extrusion extrusion area Ajy extrusion stress distribution is ____________.
reaction in the shaft19., the transmission power of a round shaft is 100kW, the speed is 100 revolutions per minute, and its external force even moment M0=__________N, M.
20. the deformation of the beam size and beam rigidity than __________.
21. in the mechanics of material, in order to simplify the study of the problem, especially to make the following three hypotheses on the deformation of a solid _______, _______, _______.
The 22. stepped shaft size and shown the maximum shear stress, the maximum shear stress of the AB member Max1 and BC section stress
The ratio of =_______ tau max2.
The 23. square section beam, if the load is constant and the section length is doubled, the maximum bending stress is
_______ times the original, the maximum bending shear stress is _______ times the original.
24. the dimensions and load of the cantilever beam with rectangular cross section are shown in figure,
(1) if the beam length L increased to 2L, the maximum deflection of beams increase ______ times to the original;
(2) if the beam width decreases from B, the maximum deflection of beams increase ______ times to the original;
(3) if the height of the beam is reduced by H, the maximum deflection of beams increase ______ times to the original.
25. round bar section into circular cross section area equal pressure bar, the other conditions are the same, the flexibility will _______, critical load will _______.
Two, individual choice questions
1. a simple supported beam AB load as shown in the diagram, are now using RA and RB to indicate the support A and B at the constraint reaction force, then their relationship is ().
A.RA
B.RA>RB
C.RA=RB
D. cannot compare
2. different materials two blocks A and B stacked in the horizontal plane, known to block A block 0.5kN, B 0.2kN, f1=0.25 A, the friction coefficient of block B, f2=0.2 block B and the friction coefficient between the ground and the minimum force required to pull the B block (for).
A.0.14kN
B.0.265kN
C.0.213kN
D.0.237kN
3. Hooke's law applies to ().
A.
Only for plastic material B. only for axial tension
C. stress does not exceed the limit of proportionality, and
D. stress does not exceed the yield limit
The cross section of the 4. beam is T, and the Z axis passes through the centroid of the cross section. The bending moment diagram is shown as shown in the figure.

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