Cantilever beams, made of shape memory alloy (SMA), undergo much larger deflection in comparison to those made of other materials. Again, cantilever beams with reducing cross-section along the span show larger deflections compared to those of constant X-section beams.Furthermore, the degree of complexity will further increase if the material or physical non- linearity is involved,typically for an SMA beam.That takes such a study in the domain of geometric nonlinearity together with material nonlinearity. Problems of physical and geometric nonlinearities are always challenges for the engineers. Analysis was conducted for such a cantilever beam with reducing X- sectional area, made of SMA with highly nonlinear stress-strain curves.The book explains the numerical analysis of SMA beam and provides experimental investigation on SS beam. Initially, experiments were conducted for SS beams with non- linear stress-strain curves. In addition to the experiment,a numerical simulation have been conducted for SMA beam.Effective modulus-curvature relations obtained from the nonlinear stress-strain relations for different sections of the beam that are used for the analysis.