The work reported here is directed towards the
problem of measuring and modeling non-linear damping
in steel space frame civil engineering structures.
In order to gain a better understanding of the damping
mechanism in such structures, tests were performed on
a full scale bolted lattice structure and the results
of section A show that the joint' damping can be
represented approximately in the form:
FD =C (1 +e IXIn)
where n=1.
Other situations. where this form of non-linear
damping occurs is in the case of fluid flow past a solid
body. In offshore structures the hydro-dynamic force
due to drag effects are found to be proportional to
velocity squared. For non linear material damping, n,
takes a value of 6.
In section B. various methods of solution to
the non-linear dynamical system under random excitation
were studied and it was found that the 'Equivalent Non-
Linear Differential Equationl, (ENL) method yields a better
measure of the response of the non-linear system to white
noise excitation than other approximate methods. Analytical
expressions are derived for the mean-square response,
probability density function and level crossing rates.
With the modified IENLI method (MENL) it is shown how one
can extract the non-linear damping and excitation power
spectral density. A good correlation is obtained between
experimental and theoretical results
Is data on this page outdated, violates copyrights or anything else? Report the problem now and we will take corresponding actions after reviewing your request.