The Energy Accountancy method is used to describe the
response of a system by accounting for the various energy
components in a system, that is components describing the
input energy, the energy dissipated, and the energy
transfered by the system. These components are functions of
quantities that can be determined either through measurement
or finite element analysis of the system. This concept is
used in this study to determine the response of a small
diameter pipe containing two different fluids, air and
water. The results of this study have shown that the Snergy
Accountancy method can be used to describe the response of a
thin walled shell structure with good results. It has also
been shown in this study that in small diameter pipes the
fluid contained by the system can be considered to act as a
reactive medium in the response of the structure.