Tension structures and pressure vessels — with some remarks on boilers, bats and Chinese junks

Abstract

The easiest structures to think about are generally those which have to resist only tensile forces — forces which pull rather than push — and, of these, the simplest of all are those which have to resist only a single pull: in other words unidirectional tension, the basic case of a rope or a rod. Although simple unidirectional tension is sometimes to be seen in plants — especially in their roots — the muscles and tendons of animals provide better biological examples and so do vocal cords and spiders’ webs.

That the ship went faster through the water, and held a better wind, was certain; but just before we arrived at the point, the gale increased in force, ‘If anything starts, we are lost, sir,’ observed the first lieutenant again, ‘I am perfectly aware of it,’ replied the captain, in a calm tone; ‘but, as I said before, and you must now be aware, it is our only chance. The consequences of any carelessness or neglect in the fitting and securing of the rigging will be felt now; and this danger, if we escape it, ought to remind us how much we have to answer for, if we neglect our duty,’ Captain Marryat, Peter Simple