Multi-parameter optimization of lime composite design using a modified downhill simplex method

A method for the optimization of lime composite design is proposed to find a compromise between their mechanical and thermal properties. In the first step, several composite mixtures are prepared using a common empirical approach. The measured material parameters of the initial set of composites are then used as starting point for the application of a modified downhill simplex method. In the multi-parameter optimization procedure, compressive strength and thermal conductivity are included into one objectivity function. The physical limitations such as nonnegative weight or weight ratios are defined, and all simplex modifications leading to faster convergence towards sought optimum are consolidated into one step to accelerate the optimization process. The obtained results show a 2.2 times higher compressive strength and 1.7 times lower thermal conductivity, as compared with the best solution achieved in an empirical way, after only two optimization steps. This makes the modified downhill simplex method a prospective tool in the field of composite mix design.