应用有限元方法建立土质路基上 CRTS III 型板式无砟轨道系统空间耦合模型，研究路基不均匀沉降作用下板式轨道的受力和变形特性，以及路基发生不均匀沉降时底座板和路基表层之间接触应力和脱空区域的变化规律。结果表明：路基发生不均...应用有限元方法建立土质路基上 CRTS III 型板式无砟轨道系统空间耦合模型，研究路基不均匀沉降作用下板式轨道的受力和变形特性，以及路基发生不均匀沉降时底座板和路基表层之间接触应力和脱空区域的变化规律。结果表明：路基发生不均匀沉降时，无砟轨道结构在重力作用下会发生跟随性变形；轨道板、自密实混凝土和底座板在路基沉降作用下的应力受路基沉降波长和幅值的综合影响，路基沉降幅值越大，轨道各层受力越大，波长为20～30 m 的路基沉降对轨道应力的影响较大；底座板和路基表层间的接触应力和脱空区域随着路基沉降幅值的增大而增大，随着路基沉降波长的增大出现先增大后减小的变化趋势。由此可见，路基不均匀沉降会对轨道结构的受力和变形产生明显影响，严重时会造成轨道脱空，对行车安全舒适性产生较大影响，应加以严格控制。展开更多
为了分析WJ-7型扣件弹条成型后的强度和工作时的受力状态,首先通过拉伸试验得到成型后弹条材料的抗拉强度;然后采用MIDAS有限元软件进行数值模拟,得到弹条在不同扣压力下的等效应力分布规律;最后通过应变电测方法,得到弹条在不同扣压力...为了分析WJ-7型扣件弹条成型后的强度和工作时的受力状态,首先通过拉伸试验得到成型后弹条材料的抗拉强度;然后采用MIDAS有限元软件进行数值模拟,得到弹条在不同扣压力下的等效应力分布规律;最后通过应变电测方法,得到弹条在不同扣压力下各测点的等效应力。结果表明:不同扣压力作用下弹条最大等效应力均在弹条跟端位置,且在扣压力为12 k N时弹条跟端等效应力超过弹条的抗拉强度,但由于预压和抛丸工艺对弹条表面的强化作用,不会导致弹条失效。展开更多
Based on genetic algorithm and neural network algorithm,the finite element analyses on the temperature fields and stress fields of multi-track laser cladding were carried out by using the ANSYS software.The results sh...Based on genetic algorithm and neural network algorithm,the finite element analyses on the temperature fields and stress fields of multi-track laser cladding were carried out by using the ANSYS software.The results show that,in the multi-track cladding process,the temperature field ellipse leans to the cladding formed,and the front cladding has preheating function on the following cladding.During cladding,the longitudinal stress is the largest,the lateral stress is the second,and the thickness direction stress is the smallest.The center of the cladding is in the tensile stress condition.The longitudinal tensile stress is higher than the lateral or thickness direction stress by several times,and the tensile stress achieves the maximum at the area of joint between the cladding and substrate.Therefore,it is inferred that transversal crack is the most main crack form in multi-track laser cladding.Moreover,the joint between cladding and substrate is the crack sensitive area,and this is consistent with the actual experiments.展开更多
文摘应用有限元方法建立土质路基上 CRTS III 型板式无砟轨道系统空间耦合模型，研究路基不均匀沉降作用下板式轨道的受力和变形特性，以及路基发生不均匀沉降时底座板和路基表层之间接触应力和脱空区域的变化规律。结果表明：路基发生不均匀沉降时，无砟轨道结构在重力作用下会发生跟随性变形；轨道板、自密实混凝土和底座板在路基沉降作用下的应力受路基沉降波长和幅值的综合影响，路基沉降幅值越大，轨道各层受力越大，波长为20～30 m 的路基沉降对轨道应力的影响较大；底座板和路基表层间的接触应力和脱空区域随着路基沉降幅值的增大而增大，随着路基沉降波长的增大出现先增大后减小的变化趋势。由此可见，路基不均匀沉降会对轨道结构的受力和变形产生明显影响，严重时会造成轨道脱空，对行车安全舒适性产生较大影响，应加以严格控制。
文摘为了分析WJ-7型扣件弹条成型后的强度和工作时的受力状态,首先通过拉伸试验得到成型后弹条材料的抗拉强度;然后采用MIDAS有限元软件进行数值模拟,得到弹条在不同扣压力下的等效应力分布规律;最后通过应变电测方法,得到弹条在不同扣压力下各测点的等效应力。结果表明:不同扣压力作用下弹条最大等效应力均在弹条跟端位置,且在扣压力为12 k N时弹条跟端等效应力超过弹条的抗拉强度,但由于预压和抛丸工艺对弹条表面的强化作用,不会导致弹条失效。
基金Project(HIT(WH)200711)supported by the Study Fund of Harbin Institute of Technology at Weihai,China。
文摘Based on genetic algorithm and neural network algorithm,the finite element analyses on the temperature fields and stress fields of multi-track laser cladding were carried out by using the ANSYS software.The results show that,in the multi-track cladding process,the temperature field ellipse leans to the cladding formed,and the front cladding has preheating function on the following cladding.During cladding,the longitudinal stress is the largest,the lateral stress is the second,and the thickness direction stress is the smallest.The center of the cladding is in the tensile stress condition.The longitudinal tensile stress is higher than the lateral or thickness direction stress by several times,and the tensile stress achieves the maximum at the area of joint between the cladding and substrate.Therefore,it is inferred that transversal crack is the most main crack form in multi-track laser cladding.Moreover,the joint between cladding and substrate is the crack sensitive area,and this is consistent with the actual experiments.
