Effects of Temperature on the Performance of Footwear Foams Subjected to Quasi-Static Compression Loading

摘要

Diabetic ulcers are the most common foot injuries leading to lower extremity amputation [1]. Early detection and appropriate treatment of these ulcers may prevent the majority of amputations [2]. One of the most important factors in causing such injuries is the friction of the foot on the ground which produces heat and induces a non-homogeneous elevation of temperature in the foot. This elevation varies according to the kind of quasi - static and dynamic movements and to the ability of the footwear materials to evacuate the heat. Due to the usage of footwear the heat is transferred to the shoe components (midsole and insole), resulting in temperature increases in those parts. Midsole temperature readings taken with an infrared laser thermometer in the laboratory after running for five minutes showed an increase of 10°C from the ambient temperature to ~35°C. Any increase or decrease in the footwear foam temperature will affect the material properties. Therefore, variations in the foam temperature affect its stress - strain response. The current study introduces a testing method to investigate the behavior of some of the most commonly used foams in the footwear industry by subjecting them to quasi-static compression loading under varying temperature conditions.