加工硬化特性对无铆钉接头力学性能影响的研究

以6063铝合金为基础,通过修改硬化指数构造了一组新的材料.建立了无铆钉接头力学性能有限元模型,对不同材料的接头抵抗轴向载荷的力学性能进行了数值模拟,并引入加工硬化影响因子β来表征不同材料加工硬化特性对无铆钉接头抵抗轴向载荷力学性能的影响程度.试验结果表明,加工硬化特性能加强无铆钉铆接接头力学性能,且对接头失效模式有一...     

高职工程制图课程教学中创新能力的培养

结合工程制图课程的教学实际,从培养学生的创新意识、创新思维和创新能力等方面着手,介绍了在制图课程教学中如何培养学生的创新能力。     

级配碎石压实特性的研究

级配碎石的研究和应用,主要在于通过取得高质量的碎石,获得高密度的良好级配以及良好的施工压实手段来提高级配碎石的强度和稳定性。分析了级配碎石物理性能指标和影响级配碎石性能的因素,从材料选择、级配设计、不同机械组合及碾压方式方面入手,研究了级配碎石施工的压实特性和提高压实强度的方法,并通过具体试验路段进行了验证,总结了级配碎石的压实特性。     

关于客车雨刷器执行机构失效问题的分析与解决

文章针对客车前挡风玻璃上的雨刷器各部件由于安装精度不够,造成雨刷器的执行机构失效,表现形式为烧保险、烧继电器、烧电机、烧电线等现象,造成车辆在下雨天不能正常使用,或根本不能使用,直接导致汽车客车晚点、停运、甚至引发交通事故,给运输企业、承包单位、乘客、社会带来较大的经济损失和社会问题,进行了分析与研究,并从汽车生产过程...     

船机电系统自主控制平台及资源分配策略

针对船机电系统大多依旧基于“人在回路”通讯及独立决策模式,难以进一步精简人员配置和提升运行效能的问题,提出一种船机电系统自主控制平台。该平台采用多代理（Multi-Agent）分级控制结构联合船机电系统,基于资源分配策略模型自主进行系统资源分配与任务调度,使舰船平台具备无人监督时的自重构与自决策执行能力,实现船机电系统作业模式从传统的基于人员运行向自主运行转变。试验表明,该平台能够自主结合任务需求和环境条件进行决策评估与资源优化,可有效提高舰船平台的整体生命力和任务执行效能。     

高速铁路连续梁通用参考图修编设计与优化

为能够更好地满足国内下一步高速铁路建设需要,对时速350 km高速铁路预应力混凝土连续梁通用参考图进行进一步修编意义重大。通过充分借鉴我国已建和在建高速铁路的建设经验,对施工情况和运营要求进行充分的调研后进行修编设计与优化。增编了(32+48+32) m连续梁;对桥面宽度及布置形式进一步调整;桥面无砟轨道结构适应类型增加了CRTSⅢ型板式无砟轨道;取消跨中横隔板及支点局部加宽;优化滴水槽位置;根据最新锚具技术条件调整纵向预应力筋布置;取消横向、竖向预应力筋;对梁体、0号块、边跨现浇段、锯齿块的钢筋布置进行优化;增补了临时固结、合龙段刚性连接设计图;中支点一侧底板设置进人孔,并预留了顶梁构造和空间。设计中对连续梁的适应类型、结构构造、预应力筋布置、普通钢筋布置、施工工艺进行了全方位优化设计。新技术、新工艺得到应用,结构更加合理,更便于施工和满足现场施工及运营需求,更利于保证工程质量。修编优化后的通用参考图将在高速铁路建设中发挥更加积极、重要的作用。     

基于UG的三维演示在机械制图教学中的应用研究

针对应用型本科院校机械制图教学,将UG三维软件运用于机械制图教学中,根据讲授内容和学生作业需要,建立机械制图三维模型库,在制图教学中向学生演示空间动态模型.这种动态辅助教学方法,取代传统的平面和静态辅助的教学方法.实践证明,UG软件与机械制图的有效融合,使学生更加直观地观察到模型的形成过程以及内部结构,培养了空间理解能...     

A numerical study on the installation configuration design of compliant vertical access riser (CVAR) in deepwater

In oil and gas transportation, the compliant vertical access riser (CVAR) system conducts economic and operational advantages due to its special configuration. In this paper, the static performance of the CVAR is studied by an efficient numerical method. According to the unique configuration of the CVAR, the mathematical model is established based on minimum total potential energy principle. The equilibrium equations are discretized by finite difference method and then solved by Newton-Raphson technique. The accuracy of the numerical method is verified by OrcaFlex software. Detailed parametric analysis is carried out based on practical engineering requirements. The effects of buoyancy section's configuration including buoyancy factor, buoyancy section's length and buoyancy section's location, and external environmental factors including wellhead offset distance, water depth and current velocity on installation shape and mechanical properties of the CVAR are analyzed. The research shows that the presented numerical method has good applicability and flexibility for the early installation configuration design of marine risers which have no touchdown section but only one touchdown point and are equipped with multiple buoyancy blocks subjected to forces of different directions and magnitudes, such as CVARs.     

Stability of submarine bi-material pipeline-liner system with novel polyhedral composites subjected to thermal and mechanical loading fields

This study is concerned with the thermal and mechanical instability behaviors of composite novel liners encased in deteriorated pipelines. A liner may contain many connected segments, and two adjacent segments may become disconnected after long years of service. In such a case, the single disconnected segment may reduce to a ring. An innovative polyhedral configuration is introduced to improve the bending stiffness of the composite ring that is confined by the pipeline. The radius and bending rigidity of the ring are simplified analytically to facilitate the derivation of the critical buckling load. By employing the classical shell criteria, and defining an admissible displacement function, the expression of the potential energy function is obtained with only two unknown parameters. Taking the first derivative of the energy function to the two unknowns respectively generates two equilibrium equations. By solving the two equations, the analytical buckling load is obtained for a composite polyhedral ring in a thermal variational field. Then, two comparisons are taken between the present analytical predictions and results from elsewhere, and good agreements are obtained. An amplification coefficient is defined as the ratio between the buckling load of the polyhedral and circular rings. Finally, parametric evaluations indicate the amplification coefficient reduces with the increase of thickness-to-radius ratio, the increase of the number of sides, and the increase of the temperature variation, respectively. Therefore, a polyhedral ring with a low thickness-to-radius ratio is recommended in engineering applications.