Many problems concerning the behaviour of particulate solids in a vessel remain unsolved. One of them is the phenomenon of wall pressure increase arising from vibrations or impacts on the wall of the vessel. An example is the insulation of low temperature tanks whore perlite powder is packed in the central annular space of double walled tanks holding liquefied gas. Tank wall expansion or contraction, caused by temperature changes whenever liquefied gas is added or removed, packs the perlite powder more densely and to quantify the wall pressure increase and to elucidate the mechanism of the phenomenon, so, that this can be taken into account in the design of storage tanks and vessels.
In the present study the wall pressure increases due to slight impacts on the front wall of a rectangular vessel containing particulate solids have been calculated by using a Janssen type equation which has been modified by introducing an angle between the direction of the major principal stress and the horizontal axis. This was then checked against experimentally obtained data.
The results indicate that the increase in wall pressure is probably due to the change in the angle of the principal stress in the powder bed and that this, in turn,comes from the change of the arrangement of the particles.