某重型越野汽车驾驶室后悬置有限元分析及改进

本文以ANSYS软件为工具,对某型号越野汽车驾驶室后悬置支架进行受力分析,详细准确地确定了汽车驾驶室后悬置支架的受力情况和应力分布部位,依托分析结果对支架结构进行优化,达到降低驾驶室后悬置支架关键部位应力的目的,并通过实际试验进行验证,结果显示优化后的支架有效地改善了关键部位的应力,解决了支架断裂问题,提高了整个驾驶室悬置系统的可靠性能。     

箱型桥梁牛腿结构分析及裂缝产生机理研究

文章通过查阅大量文献资料,归纳总结出牛腿常见裂缝的一般特征,并以某城市立交工程为例,采用规范验算方法对其悬臂牛腿进行结构验算,同时采用有限单元法进行牛腿受力分析,结合现场检测中所看到的牛腿裂缝形态,研究牛腿倒角处裂缝产生的机理。     

大跨度悬浇钢筋混凝土拱桥合龙施工技术研究

合龙段是悬浇钢筋混凝土拱桥施工的重点和难点,其直接关系到桥梁结构成桥后的线形以及受力状态,进而决定桥梁施工完成后是否达到合理成桥状态。文章以贵州木蓬特大桥为工程背景,以其合理成桥状态为目标,利用Midas/Civil有限元分析软件对结构进行静力计算,分析了不同合龙方案、合龙温度以及拱圈合龙后的拆索顺序对成桥后主拱圈的应力和挠度的影响,为以后同类型桥梁的合龙施工提供借鉴。     

在役箱形拱桥现有承载能力安全评估研究

文章以箱形拱式旧桥为研究对象,以桥梁现行荷载标准与量测实际状况为计算依据,采用有限元分析软件Midas/Civil建立平面杆系模型,计算分析该旧桥结构现有承载能力,判定桥梁的安全工作状态。     

周期性变温作用下沥青路面温度应力有限元分析

应用ANSYS有限元软件对周期性变温作用下沥青路面温度应力进行计算,分析了不同因素对沥青路面各结构层温度应力的影响。     

Latent temporal preferences: An application to airline travel

An essential element of demand modeling in the airline industry is the representation of time of day demand—the demand for a given itinerary as a function of its departure or arrival times. It is an important datum that drives successful scheduling and fleet decisions. There are two key components to this problem: the distribution of the time of day demand and how preferred travel time influences itinerary choice. This paper focuses on estimating the time of day distribution. Our objective is to estimate it in a manner that is not confounded with air travel supply; is a function of the characteristics of the traveler, the trip, and the market; and accounts for potential measurement errors in self-reported travel time preferences. We employ a stated preference dataset collected by intercepting people who were booking continental US trips via an internet booking service. Respondents reported preferred travel times as well as choices from a hypothetical set of itineraries. We parameterize the time of day distribution as a mixture of normal distributions (due to the strong peaking nature of travel time preferences) and allow the mixing function to vary by individual characteristics and trip attributes. We estimate the time of day distribution and the itinerary choice model jointly in a manner that accounts for measurement error in the self-reported travel time preferences. We find that the mixture of normal distributions fits the time of day distribution well and is behaviorally intuitive. The strongest covariates of travel time preferences are party size and time zone change. The methodology employed to treat self-reported travel time preferences as potentially having error contributes to the broader transportation time of day demand literature, which either assumes that the desired travel times are known with certainty or that they are unknown. We find that the error in self-reported travel time preferences is statistically significant and impacts the inferred time of day demand distribution.     

Understanding ship-grounding events

The paper presents a simple procedure to estimate the damage to a ship bottom and the associated seabed topology that results from a dynamic grounding event. The seabed is modeled as a rigid body and parameterized by a quadratic surface, i.e., a paraboloid, which can in principle model a wide range of seabed topologies. A nonlinear finite element program (LS-DYNA) is used to simulate the contact force versus the lateral penetration, from which the horizontal force component of powered grounding is estimated. The simplified procedure for analyzing dynamic and static grounding events is outlined. Simulations are performed for different ship speeds and for different initial levels of obstruction over the keel. It is shown that a static approach may replace the dynamic grounding simulation, thereby considerably reducing the computational work. The static approach allows for the quick estimation of the energy absorption during powered grounding, which is imperative for decision making during critical situations. The ultimate goal of the study is to provide a near real-time prediction of the risk of rupture of the cargo tanks and hull girder failure. Moreover, the residual strength of damaged ships is an important issue that is related to operations involved in the salvage of wrecked vessels, such as re-floatation and towing.     

东平水道特大桥BIM设计及应用

为了提升东平水道特大桥的设计水平和成品质量,以达索3D体验平台和TEKLA软件为主要工具对其开展BIM设计。BIM设计过程中的技术要点包括:协同设计、骨架设计、引桥设计、钢箱梁设计、钢束设计、钢筋设计;本桥的BIM应用价值点包括用钢量统计、钢结构出图、标准验证、有限元分析、钢筋二维出图。作为国内第一座采用BIM设计的公铁两用斜拉桥,与传统设计手段相比,BIM技术的应用显著提高了其设计效率。同时,依托本项目对铁路工程信息模型数据存储标准进行了研究。东平水道特大桥BIM设计对类似工程项目具有良好的借鉴意义。     

直线式液压马达偏心轴的设计与分析

介绍一种直线式液压马达设计方案,首先对偏心轴进行受力分析,以确定偏心轴的主要结构参数,然后使用Solidworks进行三维建模,最后使用ANSYS进行强度分析,为偏心轴的研究提供理论基础。     

焊接结构变形分析系统(Weld_Sta)的开发及其应用

为使现场工程人员方便进行焊接结构变形分析,开发了一个能简单地对焊接变形有限元分析所需的数据进行前处理,对焊接变形进行计算机分析并对仿真结果进行后期处理的软件-焊接结构变形分析系统。该软件操作简便,具有自动寻找焊缝,通过固有变形数据库自动导入焊接参数,自动施加约束条件,计算模块兼容性强等多项实用功能,从而满足现场工程人员要求。并以某大型船体分段焊接变形预测为例,验证了本软件系统的实用性和可靠性。