Comfortableness Evaluation of an Autovehicle Equipped with Colloidal Suspensions

Abstract

Common autovehicle suspensions employ hydro-pneumatic absorbers placed in parallel with compression springs that provide the necessary restoring force. Since the spring can be omitted, compact and lighter design can be achieved by using the recently proposed colloidal suspensions. In this work, frontal and rear colloidal suspensions were designed to replace the classical suspensions, and tests of an autovehicle traveling on normal road with an asphalt step were performed. From the impulse response of tested autovehicle one evaluates its comfortableness, both based on the K factor method and based on the equivalent acceleration recommended by the ISO 2631 standard. Such testing method allows comfortableness evaluation without using an expensive test rig on which the autovehicle is placed over four actuators and excited to simulate the real road conditions. Results obtained are firstly validated in the case of classical suspensions consisted of oil dampers mounted in parallel with compression springs. Then, colloidal dampers with and without attached compression springs were evaluated. Relationship between the travel speed of the autovehicle and the level of vibration perception, as well as the influence on the sickness, concentration and health was obtained for various values of the tire inflation pressure. Ride-comfort decreases at augmentation of the travel speed and the tire inflation pressure. Although the colloidal suspension was found to provide inferior comfortableness than the classical suspension, results obtained are encouraging, since better performances are to be expected by optimal design of the colloidal spring.