Relationship between slip angle in ramp test and coefficient of friction values at shoe-floor interface measured with cart-type friction measurement device

Abstract

The cart-type friction measurement device developed by the authors facilitates measurement of both the static coefficient of friction (SCOF) and the dynamic coefficient of friction (DCOF) between the shoe and the floor simultaneously, as well as measurement with variation in sliding velocity. However, whether slip–resistance evaluation using this cart-type friction measurement device corresponds to the actual slip and fall risks is unclear. To investigate the validity of evaluation of slip resistance between the shoe and the floor by using the SCOF and DCOF values measured with a cart-type friction measurement device, we aimed to investigate the relationship between the slip angle in a ramp test and the coefficient of friction (COF) values between the test safety shoe and the 10 test floor sheets contaminated with a glycerol solution. The results indicate that the SCOF values and the DCOF values corresponding to sliding velocity lower than 0.3 m/s are highly correlated with the slip angle in the ramp test, which suggests that the cart-type friction measurement device can simulate the slip between the shoe and the floor in the ramp test under such sliding velocity conditions. Because the ramp test has been used widely to assess the slip resistance of floors and because the slip angle is highly correlated to the risk of slip-induced falls during level walking, the results suggest that the cart-type friction measurement device is valid and effective for assessing the slip resistance between the shoe and the floor. This study provides new information about the evaluation of slip resistance and indicates that the cart-type friction measurement device will contribute toward the prevention of slip-induced fall accidents.

Keywords

• slip resistance
• ramp test
• coefficient of friction
• floor
• shoes
• fall