Static and Dynamic load

Question

What are Static and Dynamic load and what are their significant dynamic effects?

Answer 1

Static load is the load in which force direction will remain constant with the time. Normally static load is the effect of gravity on an object or structure. Yielding is the main cause for the failure in the case of static loading. The example of static loading is weight of bridge.

Dynamic load is the force or  load that changes  its direction with the time. There are many examples like force of wind on a shining board, load on the rotating unbalance rotor or load of vehicle on the bridge. First and third case is not the periodic loading while second case is the example of periodic dynamic loading.

These are loads that display significant dynamic effects. Examples include impact loads, waves, wind gusts and strong earthquakes. Because of the complexity of analysis, dynamic loads are normally treated using statically equivalent loads for routine design of static structure. This is the graphical representatio:

The main cause of disk of  turbine  gas engine is dynamic loading only. Brittle material shows poor strength against dynamic load. Army never march on the bridge. This is also because of dynamic loading. Failure mechanism is crack propagation. Crack initiates and grow with the dynamic load.