Basic Statements 9

Question 1

Bernoulli theory assumes that a plane cross-section of a beam remains plane after bending

Answer 1

True

Question 2

Navier theory presumes that the geometry of a transverse cross-section of a beam remains unchanged when the beam is subjected to bending

Answer 2

True

Question 3

Bernoulli and Navier theories assume that the normal stress in the flange of a beam subjected to bending is uniaxial and constant over the entire flange

Answer 3

True

Question 4

The outer flange edges of a short I-beam with wide flanges deform similar to the line between the web and the flange when subjected to bending

Answer 4

False -

epsilon_A = epsilon_C inte= epsilon_B

Question 5

“Effective breadth” calculation procedure is used to re-establish the conditions of beam theory in order to carry out calculations more easily in structural design

Answer 5

True

Question 6

The concept of effective breadth aims at finding a constant strain over an imagined breadth which will give the same normal force as the real strain distribution does on the entire flange breadth

Answer 6

True

Question 7

The variation in normal stress distribution over flange breadth is caused by poor welding.

Answer 7

False - Welding have nothing to do with the normal stress.

Question 8

The non-uniform stress distribution in a flange depends solely on normal forces

Answer 8

False - Depends also on shear stress

Question 9

The normal stress distribution in a flange can depend on the boundary conditions of the flange near boundaries

Answer 9

True

Question 10

The bending moment distribution, M(x), does not contribute to the normal stress distribution in a flange

Answer 10

False - It surely does

sigma = M(x)*z/Iy

Question 11

The geometric dimensions of a beam have negligible influence on the normal stress distribution in a beam

Answer 11

False - Moment of inertia is a geometric parameter

sigma = M(x)*z/Iy