Hi... I am leanring some knowledge about vibration. For a given vibaraiton system, for example, cantilever beam, we can perform modal anlaysis and found five natural frequency of 3, 6, 8, 10 and 20 Hz (just made up) and five corresponding vibration modes. after that we give a harmonic force on the system at the mentioned natural frquencies. Will the beam give resonance response at all the natural frequencies ? If I contorl the way of force (such as acting point and direction), is it possible that no resonance occurs for some natural frequencies ?