轮胎与沥青路面微观摩擦接触特性的分子动力学模拟

Molecular dynamics simulation of micro frictional contact characteristics between tires and asphalt pavement

为了精确表征轮胎与路面微观摩擦接触特性及分子作用力效应,利用分子动力学模拟分析方法建立轮胎(聚异戊二烯)和集料(二氧化硅)三维单体模型和界面接触模型,在纳米尺度上研究轮胎和集料的微观构造和接触特性.模拟结果表明:链状聚异戊二烯分子链为螺旋状结构,分子间隙较大,易产生较大变形,而二氧化硅则为典型脆性材料,表面较为平整;界面接触模型以二氧化硅为固定基底,聚异戊二烯单链在其上匀速滑动,二者间距离为0.5 nm.接触界面摩擦特性模拟结果表明摩擦系数随着速度增加而变小,其变化趋势与实验结果相同,证明模拟结果有效.

To accurately capture micro frictional contact characteristics and intermolecular forces between tires and pavement,the three-dimensional monomer models and the interface contact model of tires represented by isoprene and aggregates represented by silica were established by the molecular dynamics method.The microscopic structure and tire-aggregate contact properties were studied in nanoscale.Simulation results show that polyisoprene molecular chain is in the spiral structure with big molecular gaps,and is easy to generate large deformation under external loading.Conversely,silica is brittle with relatively flat surfaces.In the tie-pavement contact model,silica is the fixed base,and the single-chain polyisoprene is sliding on the top of the silica base at a constant velocity.The surface distance between the silica base and the single-chain polyisoprene is 0.5 nm.Simulation results of tire- pavement contact show that the friction coefficient decreases with the increase of sliding velocity,and the relationship between the friction coefficient and sliding velocity shows good agreement with test results,indicating that molecular dynamics simulation is capable to predict the tirepavement frictional contact characteristics.