摘要：Road horizontal alignment contains three elements: straight line,circular arc,and *** AutoCAD,clothoid can only be fitted by polyline or spline,and the graphics which are separated from the road data are independent of each ***,it is necessary to develop a new curve for road horizontal ***,the differential approximation and series integration methods for clothoid were ***,the geometric formulae for road line which contain the three elements were derived as a ***,the advantages and feasibility of customizing a road line class,which was derived from the curve base class,were analyzed based on ObjectARX(AutoCAD Runtime eXtension) ***,the data structure and operations for the road line class were *** experimental results show that the road line can integrate the road elements,graphics and data to implement the graphics-oriented design,which can be widely used in road alignment design.

摘要：Virtual dynamic optimization design can avoid the repeated process from de-sign to trial-manufacture and *** designer can analyze and optimize the productstructures in virtual visualization *** design cycle is shortened and the costis *** paper analyzed the peculiarity of virtual optimization design,and put for-wards the thought and flow to implement virtual optimization *** example to opti-mize the internal grinder was studied via establishing precise finite element model,modi-fying the layout of Stiffened Plates and designing parameters of the worktable,and usingthe technology of modal frequency revision and the technology of multiple tuned *** result of optimization design compared the new grinder with the original grinder showsthat the entire machine's first orders natural frequency is enhanced by 17%,and the re-sponse displacement of the grinding-head has dropped by 28% under the first order natu-ral frequency and by 41% under second order natural ***,the dynamic per-formance of the internal grinder was optimized.

摘要：Meshless method is a type of promising numerical approach. But for the method, the convergence is still lack of common theoretical explanations, and the technique of numerical implementation also remains to be improved. It is worth noting that a kind of uniformly defined intervention point is used in many existing schemes. Therefore, the intervention-point principle is proposed. The viewpoint is likely to give a reasonable explanation for the inaccuracy and instability of the collocation method. Based on the principle, a design process for a new scheme was demonstrated. Some initial numerical tests were also offered. The results have revealed the intervention point to take effect on convergence, suggested a construction concept using intervention point for meshless collocation method, and presented a new scheme of meshless method for application.

摘要：According to the shearing force character and the deformation coordination condition of shell at the station of supports, the mathematical models to calculate contact angle and contact pressure distribution between tyre and shell were set up, the formulae of bending moment and bending stress of tyre were obtained. Taking the maximum of tyre fatigue life as the optimal objective, the optimization model of tyre support angle was built. The computational results show that when tyre support angle is 30°, tyre life is far less than that when tyre support angle is optimal, which is 35.6°, and it is unsuitable to stipulate tyre support angle to be 30° in traditional design. The larger the load, the less the nominal stress amplitude increment of tyre, the more favorable the tyre fatigue life when tyre support angle is optimal.

摘要：To ensure running safety,the secondary spring loads of railway vehicles must be well *** to the coupling interactive effects of these hyper static suspended structures,the equalization adjustment through shimming procedure is quite ***,an effective and reliable method in application is developed in this ***,the best regulation of spring load is solved based on a mechanical model of the secondary suspension system,providing a target for actual *** reveal the relationship between secondary spring load distribution and shim quantity sequence,a forecasting model is constructed and then modified experimentally with consideration of car body’s elastic ***,a gradient-based algorithm with a momentum operation is proposed for the load *** of the whole method has been verified on a test *** is experimentally confirmed that this research provides an important basis for achieving an optimal regulation of spring load distribution for multiple types of railway vehicles.

摘要：This paper presents a bi-level hybrid local search(BHLS)algorithm for the three-dimensional loading problem with balancing constraints(3DLP-B),where several rectangular boxes with even densities but different sizes are loaded into a single cubic bin to meet the requirements of the space or capacity utilization and the balance of the center of *** proposed algorithm hybridizes a novel framed-layout procedure in which the concept of the core block and its generation strategy are *** the block-loading sequence has been determined,we can load one block at a time by the designed construction ***,the double-search is introduced;its external search procedure generates a list of compact packing patterns while its internal search procedure is used to search the core-block frames and their best distribution *** approach is extensively tested on weakly to strongly heterogeneous benchmark *** results show that it has better performance in improving space utilization rate and balanced condition of the placement than existed techniques:the overall averages from 79.85%to 86.45%were obtained for the balanced cases and relatively high space-usage rate of 89.44%was achieved for the unbalanced ones.

摘要：In order to study the application of gyratory compaction molding method in emulsified asphalt cold recycled mixture and optimize the relevant technical parameters, the study was carried out according to splitting strength, stability and water stability test;the design of the experiment involved changing gyration number, emulsified asphalt and water content, molded specimen temperature and other factors to analyze the volume parameters, mechanical properties and water stability. The results show that both the maximum dry density and dry and wet splitting strength ratio(DWSSR) of emulsified asphalt cold reclaimed mixture are improved by the rotary compacting method, while the porosity and the optimal dosage of water are reduced. Furthermore, with the increase of compaction times, the porosity and splitting strength index both change exponentially. DWSSR and porosity are consistent with quadratic functions. The use of gyratory compaction for 70 times at 25 °C and the optimum dosage of emulsified asphalt can be determined based on the splitting strength ratio. The high-temperature stability and water damage resistance of the pavement can be improved by the use of rotary compacting method effectively, and the early strength and road performance are higher than the regulatory requirements.

摘要：路基土的变形特性对路基结构设计和路面耐久性保持十分重要。回弹模量(M_(R))和永久变形(PD)是分别表征路基土弹塑性变形的重要指标。本文旨在通过动三轴试验探究路基黏土在偏应力、围压、含水率、加载次数及冻融循环次数条件下的变形特性演变规律。结果表明:冻融循环次数对M_(R)和PD的影响显著,且其在第1次冻融循环中衰减幅度最大,在第6次冻融循环中衰减趋于稳定。同时,在前2000次加载过程中,M_(R)迅速衰减而PD急剧增加。提出并验证了一个综合考虑偏应力、围压、含水率、加载次数及冻融循环次数影响的PD预估模型。研究结果可为路基黏土在冻融循环作用下的变形特性分析提供有效参考。

摘要：This study investigates the influence of different pantograph parameters and train length on the aerodynamic drag of high-speed train by the delayed detached eddy simulation(DDES) method. The train geometry considered is the high-speed train with pantographs, and the different versions have 3, 5, 8, 10, 12, 16 and 17 cars. The numerical results are verified by the wind tunnel test with 3.6% difference. The influences of the number of cars and the position, quantity and configuration of pantographs on flow field around high-speed train and wake vortices are analyzed. The aerodynamic drag of middle cars gradually decreases along the flow direction. The aerodynamic drag of pantographs decreases with its backward shift, and that of the first pantograph decreases significantly. As the number of pantographs increases, its effect on the aerodynamic drag decrease of rear cars is more significant. The engineering application equation for the aerodynamic drag of high-speed train with pantographs is proposed. For the 10-car and 17-car train, the differences of total aerodynamic drag between the equation and the simulation results are 1.2% and 0.4%, respectively. The equation generalized in this study could well guide the design phase of high-speed train.

摘要：Seeking for innovative structures with higher mechanical performance is a continuous target in railway vehicle crashworthiness *** the present study,three types of hexagonal reinforced honeycomb-like structures were developed and analyzed subjected to out-of-plane compression,namely triangular honeycomb(TH),double honeycomb(DH)and full inside honeycomb(FH).Theoretical formulas of average force and specific energy absorption(SEA)were constructed based on the energy minimization *** validate,corresponding numerical simulations were carried out by explicit finite element *** agreement has been observed between *** results show that all these honeycomb-like structures maintain the same collapsed stages as conventional honeycomb;cell reinforcement can significantly promote the performance,both in the average force and SEA;full inside honeycomb performs better than the general,triangular and double schemes in average force;meanwhile,its SEA is close to that of double scheme;toroidal surface can dissipate higher plastic energy,so more toroidal surfaces should be considered in design of thin-walled *** achievements pave a way for designing high-performance cellular energy absorption devices.