穿越公路管道应力分析及ANSYS二次开发

Stress Analysis of Pipeline Crossing Highway and Secondary Development of ANSYS

为了研究穿越公路管道应力分布状态,采用ANSYS 14.5软件对穿越公路管道进行三维及二维有限元建模,进行模拟分析。由于在实际工程现场应用中,ANSYS 14.5软件建模困难,效率不高,因此,结合C#可视化编程技术和APDL结构化语言对ANSYS 14.5软件进行了二次开发,开发出方便现场工程技术人员应用的穿越公路管道应力分析系统。根据模型特点,应力应变计算采用三维有限元模型,极限载荷计算采用二维有限元模型,可以提高穿越公路管道应力应变分析效率,为穿越公路管道安全评估提供依据。在实例模拟分析中,钢质管道垂直穿越沥青混凝土路面公路,路宽为20 m,管道规格为D159×6,管材为Q235B,外覆3PE防腐层,施加管道内压1.5 MPa、土体重力载荷(管底埋深分别取0.5、1.0、1.5、2.0、2.5、3.0、3.5 m)、标准车载0.7 MPa。模拟结果表明:相同埋深时二维模型管中心顶部应力比三维模型大,但两者变化规律基本一致:埋深大于2 m时,受车载影响较大;埋深小于2 m时受覆土压力影响较大,故管中心顶部应力呈现先减小后增大的趋势。三维模型可以分析管道纵向和环向的力学特性,适用于分析特定载荷下的穿越公路管道的应力应变状态;二维模型只考虑管道环向应力应变,但二维模型的计算时长远远小于三维模型,可以迭代试算出穿越公路管道达到失效时所能承受的极限载荷。

In order to study the stress distribution state of the pipeline crossing the highway,ANSYS 14.5 software was used to establish the three-dimensional and two-dimensional finite element model of the pipeline crossing the highway for simulation analysis.Due to the difficulty in modeling and low efficiency of ANSYS 14.5 software in actual engineering field applications,the secondary development of ANSYS 14.5 software was carried out by combining C#visual programming technology and APDL structured language and a stress analysis system for the pipeline crossing highway was developed,which is convenient for field engineering technicians.According to the characteristics of the model,three-dimensional finite element model is used for stress-strain calculation,and two-dimensional finite element model is used for ultimate load calculation,which can improve the efficiency of stress-strain analysis of the pipeline crossing highway and provide basis for safety assessment of the pipeline crossing highway.In the case simulation analysis,the steel pipeline vertically crosses the asphalt concrete pavement highway,the road width is 20 m,the pipeline specification is D159×6,the pipe material is Q235B,covered with 3PE anti-corrosion layer.The internal pressure of the pipeline is 1.5 MPa,the soil gravity load depends on the buried depth of the pipe bottom(0.5,1.0,1.5,2.0,2.5,3.0 and 3.5 m),and the standard vehicle load is 0.7 MPa.The simulation results show that the stress at the top of the pipe center of the 2D model is greater than that of the 3D model at the same buried depth,but the change law of the two models is basically the same:when the buried depth is greater than 2 m,it is greatly affected by the vehicle load;when the buried depth is less than 2 m,it is greatly affected by the overburden pressure,so the stress at the top of the pipe center decreases first and then increases.The 3D model can analyze the longitudinal and circumferential mechanical properties of the pipeline,and is suitable for analyzing the stress-strain state of the pipeline crossing highway under a specific load;the 2D model only considers the circumferential stress-strain of the pipeline,but the calculation time of the 2D model is much shorter than that of the 3D model,so the ultimate load that the pipeline crossing highway can withstand when it fails can be calculated iteratively.