"In the preceding chapter we analyzed the stresses and strains at a point in a structure subjected to plane stress. Plane stress is a common condition that exists in all ordinary structures, including buildings, machines, vehicles, and aircraft... The first structures to be discussed are pressure vessels, such as compressed air tanks and water pipes. We will determine the stresses and strains in the walls of these structures due to the internal pressures from the compressed gases or liquids. Next we return to the subject of stresses in beams and show how to determine the principal stresses and maximum shear stresses at various points. Finally,..., we analyze structures subjected to combined loadings, that is, combinations of axial loads, torsional loads, bending loads, and internal pressure. Our objective is to determine the maximum normal and shear stresses at various points in the structure."

ABSOLUTE PRESSURE
A MEASURE OF THE TOTAL FORCE EXERTED PER UNIT OF AREA

PRESSURE
THE FORCE OR LOAD PER UNIT OF AREA.

PRESSURE VESSELS
CLOSED CONTAINERS THAT MUST BEAR THE LOAD OF A FLUID FROM THE INSIDE AND/OR THE OUTSIDE.

SHELL STRUCTURES