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采用基于振动周期内平均功率相等的描述函数法,对重载货车转向架的非线性干摩擦力进行等效线性化,即将斜楔与摇枕间的垂向和横向非线性摩擦力线性等效为垂向和横向线性阻尼力,将旁承和心盘处的回转摩擦阻力矩线性等效为同转摩擦阻尼力,进而建立重载货车的等效线性动力学模型.以C80型重载货车为例,分别采用给出的等效线性动力学模型和非线性动力学模型进行重载货车动力学仿真计算.结果表明:等效线性动力学模型虽然小幅度增大了车体的垂向和横向平稳性指标、轮轨横向作用力、脱轨系数和轮重减载率,但是仍在GB/T 5599-1985标准范围内,满足其各项评价指标要求,验证了用描述函数法对非线性干摩擦力等效线性化的正确性和合理性;说明基于描述函数法的重载货车等效线性动力学模型可以替代复杂的非线性动力学模型进行重载货车通过既有桥梁的车桥耦合动力响应分析,为重载货车的非线性悬挂系统参数优化和车桥耦合动力学性能分析提供了新的有效途径. 相似文献
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四面体单元下预应力等效荷载计算 总被引:1,自引:0,他引:1
预应力混凝土结构在桥梁设计中有着广泛的应用,预应力作用转换为等效荷载的方式在桥梁结构分析中应用越来越广。现今预应力等效荷载的方式主要应用于梁单元,很少应用于体单元,这使精确性受到限制。使用体单元对混凝土桥梁进行体系受力分析计算时,预应力等代荷载计算具有一定的特殊性。针对四面体单元提出一种数值计算方法,推导出四面体单元下预应力等效荷载公式,能直接求解四面体单元下预应力钢束的等效荷载。并以某连续刚构桥为实例,检验提出的四面体单元下预应力等效荷载计算的正确性。 相似文献
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基于测姿GPS及电子罗盘组合的姿态估计算法 总被引:1,自引:0,他引:1
针对低成本姿态测量应用需求,研究了由测姿GPS与电子罗盘组合的姿态估计算法。以捷联姿态误差模型为基础,利用等效倾角误差表示姿态误差,引入角速率误差作为状态参量,通过四元数微分方程推导等效倾角误差传递模型。从GPS双差载波相位测量方程和电子罗盘地磁矢量方程出发,从观测量的物理意义出发推导了等效倾角误差为状态参量的非线性观测方程。采用扩展卡尔曼滤波对姿态参数进行状态估计。车载实验表明该算法能够有效地提高姿态测量精度和系统的鲁棒性,具有较好的实用性。 相似文献
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Effect of pitting corrosion on the ultimate strength of steel plates subjected to in-plane compression and bending 总被引:2,自引:0,他引:2
Tatsuro Nakai Hisao Matsushita Norio Yamamoto 《Journal of Marine Science and Technology》2006,11(1):52-64
Corrosion pits with a circular cone shape are typically observed on coated hold frames of aged bulk carriers which carry exclusively
coal and iron ore. In order to ensure the safety of these types of bulk carrier, it is necessary to understand the effect
of pitting corrosion on the local strength of hold frames. In order to investigate this effect, a series of nonlinear finite-element
(FE) analyses has been performed with pitted plates subjected to in-plane compressive loads and bending moments. It has been
shown that the ultimate compression load or bending moment of pitted plates is smaller than that of uniformly corroded plates
in terms of average thickness loss, and that predictions of the ultimate strength using the average thickness loss at the
minimum cross section would be conservative. In order to establish a method of evaluating strength reduction due to pitting
corrosion, it is important to identify the failure mode that would be most detrimentally affected by pitting corrosion. It
was found that the reduction of the ultimate compressive load or bending moment due to pitting corrosion is smaller than that
of the tensile strength in terms of equivalent thickness. 相似文献
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This paper examines the possible placement of Energy Storage Systems (ESS) on an urban tram system for the purpose of exploring potential increases in operating efficiency through the examination of different locations for battery energy storage. Further, the paper suggests the utilisation of Electric Vehicle (EV) batteries at existing Park and Ride (P&R) sites as a means of achieving additional energy storage at these locations. The study achieves this through MATLAB modelling utilising captured GPS data and publically available information. This study examines the scenario of uni-directional substations with no interconnection between the overhead catenary for both directions of travel, and discusses the trade-offs between ESS size and required current limits.The results show the savings in both energy and basic CO2 emissions alongside the discussion of Return on Investment (RoI) that can be achieved through the potential installation of ESS at identified ideal locations along the tram network. Moreover, this may be extended to the use of EVs as stationary ESS sited at the existing P&R facilities. Further, the model may also be used to inform future infrastructure upgrades and potential improvements to air quality within urban environments. 相似文献