10.0 Analogy of Rod as a Spring

  Elasticity

$$\begin{equation} \begin{aligned} Y = \frac{{Stress}}{{Strain}} \\ Y = \frac{{Fl}}{{A\Delta l}} \\ F = \frac{{AY}}{l}\Delta l \\\end{aligned} \end{equation} $$

$\frac{{AY}}{l} = constant$, depends on type of material and geometry rod. $$F = k\Delta l$$ $${\text{where}}k = \frac{{AY}}{l} = equivalent\ spring\ constant.$$

So, the rod can be treated as a spring. Therefore different combination of several rods can be easily solved by assuming the combination of spring.