多重随机因素作用下钢轨疲劳裂纹萌生与扩展寿命预测研究

项目名称： 多重随机因素作用下钢轨疲劳裂纹萌生与扩展寿命预测研究

项目编号： No.51208319

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 建筑环境与结构工程学科

项目作者： 王建西

作者单位： 石家庄铁道大学

项目金额： 25万元

中文摘要： 钢轨踏面疲劳裂纹是钢轨常见伤损之一，它破坏轮轨关系，增加养护维修费用，其扩展甚至会导致钢轨折断，危及行车安全；随着列车速度提高和轴重增加，钢轨踏面疲劳裂纹呈增加趋势。本项目拟建立车辆-轨道耦合动力学模型，研究轮轨力的幅频特性和轮轨接触位置的分布特征，探求这两随机量的联合概率分布，编制随机载荷谱；利用试验获得的循环应力-应变曲线，建立轮轨接触非线性模型，研究随机载荷谱作用下钢轨应力-应变场的变化；利用损伤力学理论和断裂力学理论，估算疲劳裂纹萌生与扩展寿命；采用神经网络模拟疲劳裂纹萌生扩展寿命与轮轨接触位置、轮轨力和材料性能参数等各随机因素之间的非线性关系；运用Monte-Carlo仿真，研究多重随机因素作用下疲劳裂纹萌生和扩展寿命概率分布特性，分析各参数对疲劳裂纹萌生和扩展寿命的影响，揭示钢轨疲劳损伤机理。本项目的研究成果将丰富钢轨损伤力学研究内容，为钢轨养护维修和服役安全提供理论支持。

中文关键词： 铁路；钢轨；疲劳裂纹；萌生；非对称钢轨型面

英文摘要： Rail tread fatigue crack is one of rail common defects. It undermines the relationship between wheel and rail, increasing the maintenance costs. Even fatigue crack propagation causes the rail to break, endangering traffic safety. With the train speed and axle load increasing, rail tread fatigue crack is more serious trend. The project will establish three-dimensional wheel/rail coupling dynamics model using the actual wheel and rail profiles to study the distributions of wheel/rail forces and locations of wheel/rail contact.Then a random load spectrum will be made according to the joint probability distribution of the two random fatctors. Based on experimentally obtained cyclic stress-strain curve, a nonlinear finite element model of wheel and rail will be established to study of the rail stress/strain field under the random load spectrum. The fatigue crack initiation and propagation lives will be predicted based on the rail stress/strain field using Theory of damage mechanics and Theory of fracture mechanics. Then, a neural network will be used to simulate the nonlinear relationship between fatigue crack initiation and propagation lives and the various random factors (such as wheel/rail contact location, wheel/rail forces and material properties parameters). By using Monte-Carlo simulation, the characteristi

英文关键词： railway；rail；faitigue crack；crack initiation；asymmetric rail profile