[Dr.Manjeet Singh]

Originally Posted by windyridge50

I think you have to think of mass, stiffness and damping as three independent variables. Obviously a heavy tripod is preferable, as for any given force input the resultant acceleration will be less, also a stiffer tripod is good for the same reason that for a fixed force input the displacement will be less. So I agree with you on this.

However once the tripod is in motion the vibration is controlled by damping. the normal way of expressing damping is by the use of a term called tan d (d is really delta but I can't get the symbol here) where tan d is the ratio of the imaginary to real component of the complex Young's modulus (E) where E*= E'+jE" and tan d=E"/E'. A structure with a tan d of 2 is called "dead beat" and for any given energy input will come to rest in less than one cycle of vibration, typical welded steel structures will have a tan d around 0.001.

Damping may be of the coulomb friction type (two bits of metal rubbing together, say in a bolted joint,) or may be tuned to a specific application by the use of a viscoelastic polymer treatment.

The general solution for any vibrating system, treated as a "lumped parameter" system is covered by a second order differential equation, but for higher frequencies, where "wave effects" can throw up a number of nasties in a "distributed system" a one-dimensional solution of the three dimensional wave equation provides a much more precise answer.

Hope this helps :-)

Yes know i am getting it.Thanks a lot.regards.