基于随机有限元的水泥路面热力耦合可靠性分析

Reliability Analysis of Cement Concrete Pavements under Thermodynamic Coupling Actions Based on Stochastic Finite Elements Method

目的基于随机有限元法,对水泥路面在温度应力与随机车辆荷载耦合作用下的可靠度问题进行研究.方法首先,通过水泥路面热传导方程,获得其在夏、冬两季典型天气条件下的温度场.然后,将温度场导入到路面力学模型中,同时将车辆荷载以随机荷载施加其上,从而实现水泥路面的热力耦合随机有限元分析.在此基础上,利用Monte Carlo法基本原理,通过对随机有限元结果中最大Mises应力的统计回归分析,确定水泥路面应力的概率分布模型与可靠度指标.结果冬、夏两不同季节,温度应力与随机车辆荷载耦合作用下路面最大Mises应力统计特征值差异显著.冬季时,水泥路面内产生的最大Mises应力均服从Log-Logistic分布,而夏季14:00时,其概率分布模型从Log-Logistic阶跃为t Location-Scale.结论通过对比分析冬、夏14:00时在随机车辆荷载作用下的路面最大Mises应力,验证了热力耦合作用是影响水泥路面可靠性的重要因素,为水泥路面的可靠性研究提供一种有效的分析方法.

The reliabilities of cement pavements(CP)were analyzed under the thermodynamic coupling actions with the stochastic finite elements methods(SFEM).Firstly,the temperature fields of CP were achieved under typical weather conditions in the two seasons of summer and winter,by CP heat transfer functions.Secondly,the temperature fields were imported into the mechanical models of the CP,and the traffic loads as the random loads were effected on the CP surface simultaneously,to achieve the thermo-mechanical coupling stochastic finite elements analysis of pavements.On this basis,the probability distribution models and reliability index of CP stresses were determined by the statistical regression analysis of the Max-Mises of the stochastic finite elements calculated results on the Monte Carlo fundamental.The calculated results indicated that the statistical characteristics of Max-Mises of CP are significantly different in the two seasons of summer and winter under thermo-mechanical coupling actions.In winter,the Max-Mises stress in the cement pavement obeys the Log-Logistic distribution,however they step changed from Log-Logistic to t Location-Scale types at 14:00 in summer.Through comparative analysis of the maximum pavement stress under random vehicle loads during winter and summer at 14:00,it was verified that thermodynamic coupling is an important factor influencing the reliability of cement pavement,and it provides an effective analysis method for the reliability study of cement pavement.