How does dynamic load effect a simply supporrted beam when it is loaded?

Question

How does dynamic load effect a simply supporrted beam when it is loaded?

Answer 1

sag , shear .

Answer 2

When a beam is loaded with a moving load, additional forces other than the weight of the moving load are generated due to small vertical accelerations of the load as it traverses across the beam. This is normally accounted for by applying a dynamic load factor on the weight of the moving load. A dynamic load factor of 1.5 is considered to be sufficient for ordinary dynamic loading. However, the effect of impact loading, which is also a form of dynamic loading, if present, should be calculated separately as impact loads can generate very high concentrated load equivalents on beams.

Answer 3

For static conditions the maximum load depends on the geometry of the beam and the maximum allowable stress.  Maximum static stress is usually below the yield strength of the material.

Dynamic loading is totally different.  Because the beam is now subjected to repeated loading, fatigue must be taken into account.  The beam can become strain hardened and fail due to brittle fracture.  This can occur at loads that are completely safe for static conditions.

It is due to this phenomena that the fatigue strength is used when analyzing beams subjected to any type of cyclic loading.

Answer 4

By dynamic load, I presume you meen a constant distributed load?

Your going to have a shear force diagram with a gradient (ie. not constant throughout) and bending moment diagram thats curved. You can do the maths on it.... Have any more info on the question?