基于C17200与34CrNiMo6材料的摩擦磨损特性与数值模拟研究

目的 探究干摩擦下载荷与速度对于C17200与34CrNiMo6材料摩擦学特性的影响，以探寻C17200材料作为风力机制动闸片的可行性，开展考虑表面粗糙度和接触压力分布不均因素的磨损深度的数值模拟。方法 以C17200与34CrNiMo6材料组成销–盘摩擦副，基于风力发电机的制动工况，利用试验探究其摩擦学特性与磨损机理。在ABAQUS中建立三维销–盘平面/平面磨损模型，设置不同载荷与速度，基于销–盘摩擦副理论模型与UMESHMOTION子程序，结合ALE自适应网格技术，对不同工况下的表面磨损深度进行数值计算，通过试验验证提出的理论模型的合理性。结果 在载荷为3 MPa时，随速度的增加，平均摩擦系数先减小、后增加，速度为125.664 mm/s时，平均摩擦系数取最小值0.575；在速度为62.832 mm/s时，随载荷的增大，平均摩擦系数近似线性增大。载荷为1.5MPa时，平均摩擦系数取最小值0.509。C17200与34CrNiMo6试样的磨损量随速度与载荷的增大而增大，但转速对于磨损量的影响更大。C17200与34CrNiMo6的磨损机理主要为粘着磨损和磨粒磨损。C17200材料磨损...

Frictional Wear Properties and Numerical Simulation of C17200 and 34CrNiMo6 Materials

The work aims to investigate the effect of load and velocity on the frictional properties of C17200 and 34CrNiMo6 materials under dry friction in order to explore the feasibility of C17200 as a brake pad for wind turbines and carry out the numerical simulation of the wear depth based on the surface roughness and uneven contact pressure distribution. After heat treatment, C17200 and 34CrNiMo6 specimens were formed into a pin-disc friction pair, and the effects of load and velocity on the friction coefficient, wear loss and wear mechanism of C17200 and 34CrNiMo6 materials were investigated based on the actual braking conditions of wind turbines and the frictional properties and wear mechanism were studied by tests. A three-dimensional pin-disc specimen plane/plane wear model was established in ABAQUS and different loads and velocities were set. Considering the phenomenon of uneven contact pressure distribution at different depths of the friction surface, and the mapping relationship between actual contact and nominal contact area due to surface roughness, a theoretical model of the pin-disc friction pair based on ARCHARD wear theory was proposed. The derived wear theory was written as the UMESHMOTION subroutine of ABAQUS by the FORTRAN language to obtain the stress and wear direction of the nodes at the wear surface in small incremental steps. Combined with the ALE adaptive mesh, the local node positions were rearranged to prevent mesh distortion, and calculate the coordinates of the node positions after the wear in small incremental steps. The total wear depth based on the node displacements was obtained by accumulating the node displacements in all small incremental steps. Tests were used to verify the validity of the simulation results of the theoretical model. The average friction coefficient firstly decreased sharply and then increased slowly with the increase of velocity when the load was 3 MPa. When the velocity was 125.664 mm/s, the minimum value of friction coefficient was 0.575. When the velocity was 62.832 mm/s, the friction coefficient increased approximately linearly with the increase of the load. When the load was 1.5 MPa, the minimum value of friction coefficient was 0.509. The values of the friction coefficient were all higher than 0.4 and stable. The wear loss of C17200 and 34CrNiMo6 specimens increased with the increase of velocity and load, but the velocity had a great effect on the wear loss. The wear loss of C17200 was less than that of 34CrNiMo. The wear mechanisms of C17200 and 34CrNiMo6 were mainly adhesive wear and abrasive wear. The maximum error between the simulation results and the test results of the wear depth of C17200 material was 4.7%, less than 5%. The proposed pin-disc wear theory model takes into account the effects of roughness and uneven contact pressure distribution, which is more in line with the actual wear situation and the maximum error between the simulation results and the test results is less than 5%. The C17200 material has a stable friction coefficient and the average friction coefficient is greater than 0.4. Compared with powder metallurgy and other materials, it has lower wear loss and less damage to the anti-wear material 34CrNiMo6. After investigation and analysis, it is found that C17200 material is feasible as the material of wind turbine spindle brake pad. The application of the proposed wear model is more consistent with the actual wear state and has higher calculation efficiency and accuracy. It has certain reference significance for the calculation and prediction of wear loss of similar pin-disc friction pair materials.