FEA Optimisation of the Neutral Axis Position in a Bending Beam
Finite Element Analysis and Optimisation
In this project, confirmation was sought on the ratio of b/a that is necessary to maintain the beam’s neutral axis at the position shown in the figure.
Knowing that the axial strain along the neutral axis is always zero during bending, a global objective function to this effect was specified in the COMSOL Optimisation module. The value of the parameter a was fixed. The parameter b was specified as a control variable, and optimised with respect to a, and in accordance with the global objective function (which was to maintain the condition that the axial strain at any location in the chosen plane is zero).
The computed ratio was 0.498, which is (almost) identical to the analytical beam bending calculation based on second moments of area (which is 0.5).