Question

26.23 The moment distribution method in structural analysis can be treated as:

1. Displacement method
2. Force method
3. Flexibility method
4. First order approximate method

26.24 The method of moment distribution in structural analysis is:

1. An approximate one
2. An interative method
3. An exact one
4. None of the above

26.25 The strain energy method in structural analysis is based on the minimization of the energy with respect to:

1. Strains
2. Force
3. Stress
4. Displacement

26.26 The minimization of potential energy in structural analysis results in:

1. Equilibrium forces
2. Compatible strains
3. Exact stress-strain relation
4. Compatible deformations

26.27 The method of virtual work in the analysis of structures results in:

1. Equilibrium of forces
2. Compatible deformation
3. Stress-strain relation
4. None of the above

26.28 The units of flexural stiffness are:

1. Radians per unit moment
2. Extension per unit force
3. Moment per unit rotation
4. Flexure for bending

26.29 The extensional stiffness of a member can be defined as:

1. Moment per unit elongation
2. Force per unit extension
3. Axial force per unit elongation
4. Extension per unit force

26.30 The translational stiffness of a member can be defined as:

1. Moment per unit translation
2. Force per unit rotation
3. Shear force per unit translation
4. Translation per unit moment

26.31 The torsional stiffness of a member can be defined as:

1. Torque for unit moment
2. Torque for unit twist
3. Moment for unit torque
4. Torsion for unit shift

26.32 The flexibility of an element can be defined as:

1. Flexural moment per unit rotation
2. Flexibility per unit rotation
3. Flexibility for unit translation
4. Rotation for unit moment

26.33 The symmetrical flexibility matrix in elastic structural analysis is generated in:

1. Symmetrical structures only
2. Prismatic member structures only
3. Non-prismatic' member structures also
4. Symmetrical load condition

26.34 The cross-stiffness coefficients in elastic structural analysis are:

1. Always symmetrical
2. Symmetrical only in prismatic members
3. Symmetrical in symmetrical members only
4. Have no relation at all

26.35 The stiffness matrix in elastic structural analysis is symmetric in:

1. Prismatic members only
2. Symmetrical structures only
3. Symmetrical loads
4. Any structure

26.36 Structural instability is reached due to:

1. Exhaust of strength only
2. Due to geometry and forces on the structure
3. Shape effect only
4. Strength or shape effect

26.37 The kinematic indeterminacy of a structure is associated with:

1. Degrees of freedom
2. Equilibrium conditions
3. Additional special equilibrium conditions
4. Elastic deformation

26.38 The maximum number of external reactions that can be solved by equilibrium considerations in plane trusses is:

1. Only three
2. More than three
3. Only two
4. Three or more than three

26.39 The order of the statical external indeterminacy of a structure is equal to:

1. Iₑ=Nₑ ̶ (3 (K ̶ 1) +S)
2. Iₑ= Nₑ ̶ 3(K ̶ 1)+S
3. Iₑ= Nₑ ̶ 2(K ̶ 1)+S
4. Iₑ= Nₑ ̶ (3 (K ̶ 1) ̶ S)

where Nₑ =number of external reactions, K=spatial dimensions of the structure, S=special equilibrium conditions associated with the overall structure.

26.40 The order of the statical internal indeterminacy of a truss is equal to:

1. Iᵢ = Nᵢ ̶ KJ ̶ 3 (K ̶ 1)
2. Iᵢ = Nᵢ ̶ (2J ̶ 3)
3. Iᵢ = Nᵢ ̶ (2J ̶ 3) + S
4. Iₑ = Nᵢ ̶ (2J ̶ 3) + S)

26.41 The method of joints in the analysis of trusses gives:

1. Uncoupled equations
2. Coupled or uncoupled equations
3. Direct solution
4. Coupled equations only

26.42 Equilibrium equations at all the joints of a truss in the method of joints gives:

1. Complete solution for member forces
2. Incomplete solution for member forces
3. May or may not give the complete
4. None of the above

26.43 The Moment of a set of forces passing through a point and which are in equilibrium is:

1. Equal to zero always
2. Can be equal to zero about that point only
3. Need not be equal to zero about every point
4. Constant

26.44 The force polygon representing a set of forces in equilibrium is a:

1. Triangle
2. Open polygon
3. Closed polygon
4. Parallelogram

26.45 An ordinate in a funicular polygon represents:

1. Net shear force
2. Resultant force
3. Equilibriant
4. Bending moment

26.46 The member forces in a statically structure indeterminate truss can be obtained by graphic statics: (a) Yes

2. No
3. May be
4. By simple trial-and-error

26.47 The bending moment in a funicular arch is:

1. Always zero
2. Depends on the load

(e) Depends on the supports

(d) Depends on the section

26.48 A moving load is:

1. Static load
2. Dynamic load
3. Static or dynamic load
4. Horizontal load

26.49 The maximum bending moment caused by a set of concentrated moving loads is:

1. Always under a load close to the centroid of the loads
2. Always at the mid point of span
3. Between the mid point and the concentrated load next to the mid point of the span (d) Undefined

26.50 The influence line diagram gives either a force or deformation:

1. At a section as a unit load moves
2. Under a unit load as it moves
3. At the support as a unit load moves
4. None of the above

Answer 1

1) Moment Distribution Method is a Displacement method wherein the stiffness i.e. the load required to displace the member by unit value, is used.

2) Moment Distribution Method is an iterative method wherein for the rigid joints, the values of the moments are taken under rigorous iteration in order to get more precision in the values.

3) As per the Castigliano's Theron, the strain energy is minimalised with respect to that entity, which depends on the entity required to be determined. Here in this method, displacement is needed thus the entity with respect to which the energy is to be minimalised is force.

4) The minimalization of the potential energy provides us with the Compatible deformations, which means it makes it easier to determine the deformations. Here, the potential energy (Resilience) is the function of force and displacement. Thus in order to obtain one entity that is displacement, the effect of the other entity has to be suppressed in the function. Here that entity is force. Thus by minimalization of the potential energy we get compatible deformations.

5) Method of virtual work is similar to the method of strain energy, the only difference is, here there is a unit force applied at the required point and the displacement at the point is determined by considering the behaviour of the beam with unit load only and that with the provided load combinations. Thus this method also provides us with compatible deformations.

6) Flexural stiffness is the moment required for unit rotation. This determines how stiff is the beam for bending.

7) The extensional stiffness is the axial force required for unit elongation or unit extension.

8) The translational stiffness is the Shear force per unit translation.

9) The torsional stiffness is the Torque required for unit twist.

10) The flexibility is the rotation required for unit moment. This determines how flexible is the object for the applied unit load or moment.

From 26.33 to 26.35 have not been answered, because I am not well versed with the concepts of Matrix Methods of Structural Analysis.

11) The instability in the structural is truly attained due to the forces or loads orientation and due to the Geometry of the structure i.e. the way in which members are arranged.

12) The Kinematic indeterminacy is associated with Degrees of Freedom. The kinematic indeterminacy determines the amount of movements are allowed at the particular joint. As in the amount of freedom provided for the movement at the joints. Thus degrees of freedom are nothing but Kinematic Indeterminacy value.

13) Only 3 external reactions can be calculated using the equilibrium conditions on the plane trusses because there are only 3 equilibrium conditions. If there are 3 simultaneous equations then the maximum number of variables that can be determined are 3.

14) For 26.39 answer is (a).

15) For 26.40 answer is (b).

16) Method of joints in trusses is Either Coupled or Uncoupled equations because sometimes it needs individual or independent equations and sometimes it needs more than one equations to solve the variables.

17) The equilibrium equations won't provide the complete solutions always in method of joints. If the number of the unknown member forces is more than 3 then it won't be able to provide the exact solution.

18) The moment of forces passing through a point is zero only with respect to that point, because the value of Moment to be nonzero, there has to be some seperation between the point where the force acts and thatbwith respect to which the moment is taken.

19) The force polygon representing the set of forces in equilibrium always is a closed polygon because may it be any number of forces, the last side of the force polygon always is the resultant of all the forces.

20) The ordinate in a funicular polygon is always the Bending Moment because the funicular polygon represents the shape of the bending moment diagram.

21) The bending moment in a funicular arch is always zero because funicular arch has the shape of the funicular polygon which is exactly same as the Bending Moment diagram.

22) The maximum bending moment due to the set of concentrated loads is always under a load closer to the centroid of the loads.

23). Influence line diagram is always the value of the required entity a section as the unit load moves.

24) Moving load is static load not dynamic load because there is no variation of it in regular intervals or periods.