Virtual prototype development for comfort assessment of occupational footwear sole

Purpose: The present paper focuses on the parametric analysis of the sole of occupational footwear in order to improve the perceived human comfort. By combining real experimental tests and virtual simulations, the sensitivity of both geometric and material design factors, on comfort degree, was investigated. Method: The correlation among perceived human comfort and physical parameters, such as plantar pressures, was estimated by conducting real tests. Experimenters were asked to wear three commercial shoes and to express their perceived comfort degree. A bar-foot test was also performed. By adopting plantar sensors, plantar pressures were also monitored. Once given such a correlation, a parametric FE model of the footwear was developed. In order to better simulate the contact at plantar surface, a detailed FE model of the foot was also generated starting from CT scan images. A fractional factorial design array was, finally, used to study the sensitivity of different sets of design factors on comfort degree. In the present study only a static standing-up configuration was analyzed. Result: Findings of this research showed that sole thickness and its material highly influence perceived comfort. In particular, softer materials and thicker sole designs contribute to increase comfort degree. Discussion & Conclusion: Despite all simplifications and limitations, the proposed methodology may be successfully adopted in other industrial applications, in which the design (or re-design) of new products is driven by the satisfaction or the sensations of users