Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynam...Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynamic responses under different temperature gradients of the slab are theoretically investigated in this work.Design/methodology/approach-Considering the moving train,the temperature gradient of the slab,and the gravity of the slab track,a dynamic model for a high-speed train that runs along the CRTS Ⅲ slab track on subgrade is developed by a nonlinear coupled way in Abaqus.Findings-The results are as follows:(1)The upward transmission of the periodic deformation of the slab causes periodic track irregularity.(2)Because of the geometric constraint of limiting structures,the maximum bending stresses of the slab occur near the end of the slab under positive temperature gradients,but in the middle of the slab under negative temperature gradients.(3)The periodic deformation of the slab can induce periodic changes in the interlayer stiffness and contact status,leading to a large vibration of the slab.Because of the vibration-reduction capacity of the fastener and the larger mass of the concrete base,the accelerations of both the slab and concrete base are far less than the acceleration of the rail.Originality/value-This study reveals the influence mechanism of temperature gradient-induced periodic deformation in the dynamic responses of the train-track system,and it also provides a guide for the safe service of CRTS Ⅲ slab track.展开更多
CRT Corner cutting tube is considered as a definitive reject and will be sent to reclaim at all times. It caused lots of material loss. In this paper, a novel technology used to save CRTs corner cutting tube is presen...CRT Corner cutting tube is considered as a definitive reject and will be sent to reclaim at all times. It caused lots of material loss. In this paper, a novel technology used to save CRTs corner cutting tube is presented firstly. A set of repair system has been successfully developed to repair CRTs corner cutting tube. Then, the process technology for corner cutting repair has been excogitated by empirical studies.Finally,the correlative performances of repaired tube are evaluated. The experimental results show that the quality of repaired tube has no difference with that of normal product. The repair yield has reached above 97 percent. This new technology has contributed to improving the production yield,reducing the material consumption and decreasing the cost of color CRT production.展开更多
基金supported by National Key R&D Program of China[Grant No.2022YFB2603400]R&D Project of China State Railway Group Corporation Limited[Grant No.P2021G053]R&D Project of China Academy of Railway Science Corporation Limited[Grant No.2023YJ200].
文摘Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynamic responses under different temperature gradients of the slab are theoretically investigated in this work.Design/methodology/approach-Considering the moving train,the temperature gradient of the slab,and the gravity of the slab track,a dynamic model for a high-speed train that runs along the CRTS Ⅲ slab track on subgrade is developed by a nonlinear coupled way in Abaqus.Findings-The results are as follows:(1)The upward transmission of the periodic deformation of the slab causes periodic track irregularity.(2)Because of the geometric constraint of limiting structures,the maximum bending stresses of the slab occur near the end of the slab under positive temperature gradients,but in the middle of the slab under negative temperature gradients.(3)The periodic deformation of the slab can induce periodic changes in the interlayer stiffness and contact status,leading to a large vibration of the slab.Because of the vibration-reduction capacity of the fastener and the larger mass of the concrete base,the accelerations of both the slab and concrete base are far less than the acceleration of the rail.Originality/value-This study reveals the influence mechanism of temperature gradient-induced periodic deformation in the dynamic responses of the train-track system,and it also provides a guide for the safe service of CRTS Ⅲ slab track.
文摘CRT Corner cutting tube is considered as a definitive reject and will be sent to reclaim at all times. It caused lots of material loss. In this paper, a novel technology used to save CRTs corner cutting tube is presented firstly. A set of repair system has been successfully developed to repair CRTs corner cutting tube. Then, the process technology for corner cutting repair has been excogitated by empirical studies.Finally,the correlative performances of repaired tube are evaluated. The experimental results show that the quality of repaired tube has no difference with that of normal product. The repair yield has reached above 97 percent. This new technology has contributed to improving the production yield,reducing the material consumption and decreasing the cost of color CRT production.
