A Finite Element Method to support the materials selection phase during the insole design process

Purpose: The paper aims to define a method to support the materials selection phase during the insole design process. The proposed scientific approach is pursued adopting a finite element method to simulate the mechanical behaviour for combinations of materials to create customized insoles. The paper presents also two processes, one to design the custom made insole and the other to select the insole materials combinations with the aim to uniform the foot plantar pressure. Method: The insole design and the materials selection processes are based on the use of software tools to manage the materials properties, in order to make them as scientific as possible. A Finite Element Method is used to calculate the stress-strain relationships of a custom combination of multiple layers of materials. The contextualization of this method into the insole design process allows the proposed idea to be successfully implemented. Result: The error committed by the Materials Combinations Simulator has been verified with a large set of materials (EVA, PU and rubber). Experimental tests have been performed to evaluate the deviation with the results of the simulation model, highlighting an error less than 10%. Discussion & Conclusion: This work is a step toward a more scientific design process for custom made insoles. The possibility to simulate the mechanical behaviour of a combination of multiple materials lead to the elimination of the physical tests. The integration of the proposed Materials Combinations Simulator system with an Insole Design software tool will represents a further innovation respect the state of the art