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991.
水泥稳定碎石基层配合比设计中确定压实度控制参数的传统方法是重型击实法,与实际施工的振动碾压方法有明显不同.而采用振动成型法则与实际施工碾压方式更为接近.依托韶赣高速公路B01标路面工程对半刚性基层振动成型法配合比设计及施工技术进行分析,为该方法的推广使用提供技术参考. 相似文献
992.
993.
工程施工中的造价监理 总被引:1,自引:0,他引:1
分析工程施工中各阶段工程造价管理的特点 ,以及造价监理中造价控制的方法和关键控制点 ,对实际工程的造价监理具有借鉴意义。 相似文献
994.
高速公路工程对液化地基的处理与一般工程相比有其独特性。结合具体工程实践,应用碎石桩对某高速公路一段液化砂土地基进行处理,并对加固后的抗液化效果进行了评价。 相似文献
995.
996.
介绍一种基于嵌入式技术的电子秤,给出了测试电路、计算机控制方法及软件设计中的关键技术。同时介绍了网络化管理的实现方法。 相似文献
997.
光纤陀螺寻北仪原理及其应用 总被引:3,自引:0,他引:3
陀螺寻北仪作为一种定北装置,在军事和民用定向中应用愈来愈多。此文介绍了一种新型陀螺寻北仪——光纤陀螺仪。在对光纤陀螺仪作了简单介绍的基础上,阐述了光纤陀螺寻北仪的原理及其应用。 相似文献
998.
采用相同的叶片轴面流线载荷分布和叶轮出口环量分布规律,改变导边与随边位置设计出多个喷水推进泵叶轮。基于雷诺时均的N-S方程、SST湍流模型和多重参考坐标系对叶轮内流场进行数值模拟,结果表明:导边向进口适度延伸可减小叶片进口边的载荷,利于提高空化性能,但效率有所降低;随边倾斜参数与叶轮出口的轴面速度分布和叶片表面的压力分布特性关联。 相似文献
999.
Gao Chang Yang Liangliang Zhang Min Luo Shihui 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(3):366-384
With the increase of railway wagon axle load and the growth of marshalling quantity, the problem caused by impact and vibration of vehicles is increasingly serious, which leads to the damage of vehicle structures and the components. In order to improve the reliability of longitudinal connection model for vehicle impact tests, a new railway wagon longitudinal connection model was developed to simulate and analyse vehicle impact tests. The new model is based on characteristics of longitudinal force transmission for vehicles and parts. In this model, carbodies and bogies were simplified to a particle system that can vibrate in the longitudinal direction, which corresponded to a stiffness-damping vibration system. The model consists of three sub-models, that is, coupler and draft gear sub-model, centre plate sub-model and carbody structure sub-model. Compared with conventional draft gear models, the new model was proposed with geometrical and mechanical relations of friction draft gears considered and with behaviours of sticking, sliding and impact between centre plate and centre bowl added. Besides, virtual springs between discrete carbodies were built to describe the structural deformation of carbody. A computation program for longitudinal dynamics based on vehicle impact tests was accomplished to simulate. Comparisons and analyses regarding the train dynamics outputs and vehicle impact tests were conducted. Simulation results indicate that the new wagon longitudinal connection model can provide a practical application environment for wagons, and the outputs of vehicle impact tests agree with those of field tests. The new model can also be used to study on longitudinal vibrations of different vehicles, of carbody and bogie, and of carbody itself. 相似文献
1000.
Yinyu Nie Fengjia Liu Jian Chang Jianjun Zhang 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(3):406-427
The finite element (FE) method is essential for simulating vehicle dynamics with fine details, especially for train crash simulations. However, factors such as the complexity of meshes and the distortion involved in a large deformation would undermine its calculation efficiency. An alternative method, the multi-body (MB) dynamics simulation provides satisfying time efficiency but limited accuracy when highly nonlinear dynamic process is involved. To maintain the advantages of both methods, this paper proposes a data-driven simulation framework for dynamics simulation of railway vehicles. This framework uses machine learning techniques to extract nonlinear features from training data generated by FE simulations so that specific mesh structures can be formulated by a surrogate element (or surrogate elements) to replace the original mechanical elements, and the dynamics simulation can be implemented by co-simulation with the surrogate element(s) embedded into a MB model. This framework consists of a series of techniques including data collection, feature extraction, training data sampling, surrogate element building, and model evaluation and selection. To verify the feasibility of this framework, we present two case studies, a vertical dynamics simulation and a longitudinal dynamics simulation, based on co-simulation with MATLAB/Simulink and Simpack, and a further comparison with a popular data-driven model (the Kriging model) is provided. The simulation result shows that using the legendre polynomial regression model in building surrogate elements can largely cut down the simulation time without sacrifice in accuracy. 相似文献