Abstract
M.Ing. (Mechanical Engineering)
This report describes an investigation into structural damping in simple steel
structures. More specifictly, an attempt is made to obtain and compare the
logarithmic decrement for different types of steel structures. The effect that welded
and rivetted connections have on the logarithmic decrement is also examined. Four
different types of steel are used, namely: mild steel and three types of chromium
based steel. Vibration tests are performed on both cantiliver and simple bridge
structures. An estimate of the inherent damping that is present in the vibrating
structures are obtained from the approximate displacement-time response plots (as
obtained from vibration tests). All the step input tests are modelled with a finite
element. computer package to test the accuracy of the approximated response
functions. Shaker tests are also performed on bridge structures. On the theoretical
side the term damping is fully defined and discussed.