But if y is the displacement at A, dy/dx is the extension at A, and the force acting is a pull across A equal to Y&uodyldx, where Y is Young's modulus of elasticity.
Owing to the yielding of joints when a beam is first loaded a smaller modulus of elasticity should be taken than for a solid bar.
Is this because cast gold has a higher, or lower, modulus of elasticity compared to cobalt chromium?
In portions of the structure liable to important changes of pressure from the rise, and fall of the water and subject to the additional stresses which expansion and contraction by changes of temperature and of moisture induce, and in view of the great difficulty of securing that the average modulus of elasticity in all parts of the structure shall be approximately the same, it is probably desirable to limit the calculated load upon any external work, even of the best kind, to 15 or 20 tons per sq.
The posts are made of a molybdenum- rhenium alloy that maintains a high modulus of elasticity even at high temperatures.
