Structures Flashcards

Which of the following statements is incorrect?

a. The principal stresses represent the maximum and minimum normal stress at the

point

b. When the state of stress is represented by the principal stresses, no shear stress

will act on the element

c. When the state of stress is represented in terms of the maximum in-plane shear

stress, no normal stress will act on the element

d. For the state of stress at a point, the maximum in-plane shear stress usually

associated with the average normal stress

b. When the state of stress is represented by the principal stresses, no shear stress will act on the element

How do brittle materials fail?

a. In compression or tension

b. In Shear

a. In compression or tension

How do ductile materials fail?

a. In compression or tension

b. In Shear

b. In Shear

Is the absolute maximum shear stress always

equal to maximum in-plane shear stress?

No

Is the absolute maximum shear stress equal to

maximum in-plane shear stress when the

principal stresses have opposite sign?

Yes

Is the absolute maximum shear stress greater

than the maximum in-plane shear stress when

the principal stresses have equal sign?

Yes

Which of the following statements is unture?

a. In 2-D state of stress, the orientation of the element representing the maximum in-plane shear stress can be obtained by rotating the element by 45° from the principal plane

b. In 3-D state of stress, the orientation of the element representing the absolute maximum shear stress can be obtained by rotating the element by 45 ° about the axis defining the direction of 𝜎𝑖𝑛𝑡

c. If the in-plane principal stresses are of opposite sign, then the absolute maximum shear stress equals the maximum in-plane shear stress

d. Same as (c) but the principal stresses are of the same sign.

d. Same as (c) but the principal stresses are of the same sign

The maximum in plane shear stress plane is

oriented from principal plane at

45°

Angle of θ on the physical material element

corresponds to an angle on the Mohr’s circle of

2θ

Is the absolute maximum shear stress always

equal to maximum in-plane shear stress?

No

When the state of strain is represented by the

principal strains.

a. Shear strain is Zero

b. Shear strain is Non-zero

c. Not enough information

a. Shear strain is zero

When the state of strain is represented by the

maximum in plane shear strain.

a. Normal strain is zero

b. Normal strain is average normal strain Τ(𝜀𝑥 + 𝜀𝑦) 2

c. Normal strain is sum of normal strain (𝜀𝑥 + 𝜀𝑦

b. Normal strain is average normal strain Τ(𝜀𝑥 + 𝜀𝑦) 2

The maximum in plane shear strain plane is

oriented from principal strain plane at

45°

Plane stress cause plane strain case.

False

In strain transformation equations derived in

the class, what is the positive sign of element

orientation from the original state?

Counter-clockwise

In Mohr’s circle for strain transformation, the

center of the Mohr’s circle is at,

Average Normal Strain

Any point in Mohr’s circle for strain represents

normal and shear strain for a specific

orientation of material element.

True

Normal strain going to the right is positive axis

in drawing Mohr’s circle.

True

𝜸/𝟐 going to upward is positive axis in drawing

Mohr’s circle.

False

The slope angle theta in flexure equations is

a. Measured in degree

b. Measured in radian

c. Exactly equal to dv/dx

d. None of the above

c. Exactly equal to dv/dx

The load must be limited to a magnitude so that

not to change significantly the original geometry

of the beam. This is the assumption for

a. The method of superposition

b. The moment area method

c. The method of integration

d. All of the above

d. All of the above

Curvature is measure of

a. Change in displacement

b. Change in slope

c. None of the above

b. Change in slope

The moment-curvature equation is applicable to

a. Statically determined member only

b. Beams having uniform cross-sections only

c. Beams having constant Young’s Modulus E only

d. Beams having varying moment of inertia I.

d. Beams having varying moment of inertia I

If the material is NOT linear-elastic, which of the

following methods is not applicable in the analysis

of indeterminate structures:

a. Method of integration

b. Method of superposition

c. Moment-area method

d. All of them

b. Method of Superposition

The flexure equations imply that

a. Slope and deflection at a point of a beam are independent

b. Moment and shear at a point of a beam are independent

c. Maximum moment occurs at the locations where the shear is zero

d. Maximum moment occurs at the inflection point

c. Maximum moment occurs at the locations where the shear is zero

The Moment-Area Method is primarily used to

determine:

a. Shear force diagram

b. Bending moment diagram

c. Slope and deflection at points on a beam

d. Reaction at supports

c. Slope and deflection at points on a beam

The First Moment-Area Theorem states that the change

in slope between two points on a beam equals:

a. The shear force between two points

b. The area under the M/EI diagram between the two points

c. The deflection at the second point

d. The first moment of the M/EI diagram area about one of the points

b. The area under the M/EI diagram between the two points

The Second Moment-Area Theorem states that the

tangential deviation of point B from the tangent drawn

at point A equals:

a. The area under the M/EI diagram between the two points A and B

b. The moment of the M/EI diagram area (between A and B) taken about point B

c. The slope of the M/EI diagram at B

d. The slope of the M/EI diagram at A

b. The moment of the M/EI diagram area (between A and B) taken about point B

In the moment-area method, what does '𝑡𝑩/𝑨'

(tangential deviation of B from A) physically represent?

a. The angle between the tangents at A and B

b. The actual vertical deflection of point B

c. The vertical distance between point B on the beam and the tangent

line drawn at point A

d. The horizontal distance between A and B

c. The vertical distance between point B on the beam and the tangent

line drawn at point A