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摆线轮检测的公法线法 总被引:1,自引:1,他引:1
本文给出了摆线轮最小跨齿数的计算公式及其解的区间;确定了最小跨齿数为最佳测量跨齿数,以及包含三种修形方式的统一的公法线理论测长计算公式,该计算方法已由作者编制了计算程序,当输入摆线轮已知参数时,可准确计算出理论测量位置及理论测长. 相似文献
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Huailong Shi Jianbin Wang Chunyuan Song Wanxiu Teng 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(8):1187-1206
This investigation demonstrates the wheel wear evolution and related vehicle dynamics of high-speed trains with an operating distance (OD) of around two million kilometres. A long-term experimental test lasting two years was conducted to record the wheel profiles and structural vibrations of various trainsets. The wheel wear, namely the profile shape, worn distribution and wheelset conicity, is investigated for several continuous reprofiling cycles. Typical results are illustrated for the stability analysis, and the ride quality is examined with increasing OD. In addition, the vibration transition characteristics between suspensions are investigated in both the time and frequency domains. The experiments show that the dominant wear concentrates on the nominal rolling radius, and the wear rate increases with OD because of the surface softening resulting from the loss of wheel material. The vibration of structural components is aggravated by the increase of the equivalent conicity of the wheelset, which rises approximately linearly with the wheel wear and OD. High-frequency vibrations arise in the bogie and car body related to the track arrangement and wheel out-of-roundness, causing the ride comfort to worsen significantly. Additionally, the system vibration characteristics are strongly dependent on the atmospheric temperature. Summaries and conclusions are obtained regarding the wheel wear and related vehicle dynamics of high-speed trains over long operating times and distances. 相似文献
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With the continuous growing of the aquaculture industry and increasingly limited fish farming sites at close to shore areas both in Norway and worldwide, there is a need to develop fish farms suitable for aquaculture production in typical offshore environments. For this purpose, SALMAR has developed and deployed the Ocean Farm 1 facility for offshore fish farming.The main purpose of this paper is to develop a reliable numerical model and investigate the motion responses of the Ocean Farm 1 structure in waves and current. The established numerical model consists of the Ocean Farm 1's frame structure (with rigidly-connected circular column components), the net and the mooring system. The hydrodynamic external loads and coefficients of the frame structure are obtained by using potential flow theory. The quadratic drag load on the individual circular columns of the frame structure is formulated by a given drag coefficient. The loads on the net are formulated by using the screen model, where the Reynold number dependent lift and drag forces are formulated as a function of the solidity ratio Sn of the net, relative inflow angle and velocity. The hydrodynamic loads on the mooring lines are formulated using the Morison's equation and the structural responses of the mooring lines are obtained using a nonlinear FE model.With the developed numerical model, time domain simulations are performed. The simulation results are firstly validated against measured data from the decay tests, current tests, and regular wave tests. After the validation, numerical simulations are performed in different irregular wave and current combined weather conditions and the obtained motion response of Ocean Farm 1 are discussed and compared with available measurement data. 相似文献
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通过理论分析对比曲线梁桥与直线梁桥在计算中承受荷载的主要不同点、分析计算中应主要注意的事项.列举实例,建立空间模型分析计算预应力钢束对支座的支反力影响大小.针对现在一般曲线梁桥存在的病害提出一些防治措施. 相似文献
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Grounding experiments on soft bottoms 总被引:3,自引:0,他引:3
To verify a theoretical analysis procedure for calculation of the hull girder response of ships running aground, a series
of large-scale ship grounding experiments was performed on an artificial island made of engineered fill. The tests were conducted
by running a condemned fishing vessel up on selected beaches of the island with velocities ranging between 2m/s and 5.5m/s.
During the tests, surge, heave, and pitch accelerations were measured and also the deformations of the beach and the ship
bow. Based on these accelerations, rigid body velocities and motions were determined. The forces arising from the interaction
between the bow of the vessel and the seabed were determined by solving the equations of motions. This article describes the
analysis of the measured results and a comparison of the results from the full-scale measurements with results from a recently
developed analysis procedure for grounding on soft bottoms.
Presented at the International Conference on Technology for Marine Environment Preservation (MARIENV '95), Tokyo, Japan, September
24–29, 1995. 相似文献
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静电陀 螺稳定平台是我国静电陀螺首次在航海上的应用研究项目,其主要特点是采用 静电陀螺摆作为水平敏感元件,能在单个陀螺上通过电参数的调节使之满足无 干扰的Schuler条件。该平台主要由下列部分组成:静电陀螺摆及其控制线路;水平平台控制回路;陀螺摆径向阻尼回路以及纵横摇角度输出装置。本文主 要介绍平台原理、结构、误差分析、静电陀螺摆及其控制线路原理,以及平 台精度的室内测试和海上试验。 相似文献
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在工程实践中,Kalman滤波采用了递归滤波的方法和线性无偏最小方差准则,因而在理论上是一种最优估计,并因为这一良好的数学性质得到了广泛的应用。但是在实际测量中,在野值的影响下,Kalman滤波新息的特性遭到破坏,滤波不再准确甚至发散。针对此一现象,提出了基于"新息"序列和对新息序列进行Kalman预测的方法对测量数据进行处理的新算法。该算法利用"新息"序列进行野值点判别,利用Kalman预测的方法对野值点处的"新息"进行预测修复。仿真证明,该算法可使状态估计、野值点判别和野值点修复同时进行,并能很好地抑制滤波的发散。 相似文献