直列六缸柴油发动机悬置系统匹配策略

动力总成悬置系统性能的好坏是影响车辆乘坐舒适性和零部件耐久性的重要因素。柴油发动机工作时产生两个主要振源,一个是由发动机内部运动件回转产生,另一个是由柴油机气缸内点燃力产生,由于运动件回转振动直列六缸发动机可以被平衡,所以悬置系统匹配设计主要考虑点燃力,正是由于此力引起动力总成的侧倾。介绍悬置系统的功用,详细探讨一种悬置系统匹配的新方法,利用悬置系统的合理布置以及类型的选择达到侧倾方向和垂直方向运动的解耦,以侧倾方向的振动传递率为悬置系统的评价指标,以动力总成的自由运动空间为约束条件,匹配出隔振性能良好且寿命长久的悬置系统。     

某电控发动机匹配3吨叉车应用研究

基于一台外资品牌的3吨叉车开展某3.2L电控发动机的匹配研究,掌握3吨叉车动力系统总成匹配和发动机优化方法。本项目根据客户的需求,针对原装叉车动力系统各主要零部件进行改装设计和试制加工,完成对动力系统总成的优化匹配及换装。对改装后的叉车进行全面的性能试验验证,并与原装叉车性能进行对比分析,基本性能指标达到并超越原装机的技术水平。     

关于斗杆液压缸和铲斗液压缸匹配问题的探讨

铲斗液压缸和斗杆液压缸应合理匹配,但一直缺乏可供执行的具体要求,本文以匹配曲线的形式提出了在铲斗机构设计后,随之设计斗杆机构时应满足的设计要求,并分析了实现合理匹配的困难和设想。     

常林F系列装载机

常林股份有限公司成功开发了F系列ZL50F和ZL60F两种产品，该产品以高档的配置、卓越的性能、优美的外形、合理的价格普遍受到国内外用户的青睐。目前已通过江苏省科委组织的专家鉴定。 　　常林F系列装载机各零部件及总成的互配性和互换性良好，并充分体现了可靠性。经济性的有机结合，运用价值工程以合理的设计成本，充分发挥各部件的能力和合理的动力匹配，使整机显示出优越的作业性能。同时可根据用户需要可配装防滚翻(ROPS)或防落架(FOPS)装置，确保操作人员的安全。 (摘自《建筑机械》2000.No.9)     

利用Cruise软件对某车动力性和经济性的仿真分析

本文以某款自卸汽车动力匹配为主线,分析该车的动力性能和燃油经济性能,建立这种自卸汽车动力优化匹配的框架,为其它自卸汽车的设计和匹配提供一定参考。主要研究内容是,对现有的发动机选择合适的变速箱和主传动比,实现发动机、传动系统的最优匹配,使汽车整车的动力性能和经济性能达到较为完美合理。     

工业软管总成扣压结构及扣压工艺

本文针对工业软管总成失效的主要故障点和故障原因,详细阐述了软管总成的扣压结构形式、扣压尺寸及扣压工艺,以及他们对软管总成性能的影响,并简要介绍了软管总成扣压结构新技术及新的工艺方法。     

约束屈曲支撑在棋盘形四角锥网架中的应用分析

约束屈曲支撑(BRB)是一种滞回性能良好的减震构件,为了研究其在大跨度网架结构中的合理应用,本文以一64m跨度棋盘形四角锥网架为例用SAP2000建模分析。综合考虑BRB的特性和棋盘形四角锥网架受力特点给出了7种替换方案。对替换前后结构的地震响应做对比分析,发现BRB能有效减小网架的地震响应,且替换四周边跨中部的腹杆比替换上弦杆的减震效果好,并优选出较优减震方案,为棋盘形四角锥网架减震设计提供参考。     

基于AutoCAD数字地形图批量文字字体替换器设计与实践

数字地形图从dgn格式转换为dwg格式后,数字地形图中的文字字体不匹配,还需要再次手工替换成能被AutoCAD软件识别的黑体或宋体等文字字体,而替换文字字体的过程是重复、费时、效率比较低的工作。作者通过大量实验用VBA设计制作了一个批量文字字体替换程序,该程序能对用手工替换字体的工作进行一次性替换或批量替换处理,提高了工作效率。     

平地机柴油发动机与液力变矩器的匹配研究

平地机以柴油发动机为动力源,柴油发动机与液力变矩器配合后,可以视为一种新的动力装置。合理的匹配能使平地机获得较好的牵引特性,对载荷的波动有自动适应性,能减少振动和冲击,避免发动机熄火,减少换挡次数,从而充分利用发动机功率。液力变矩器与发动机的匹配是否合理,对其各自性能的发挥及平地机的整车动力性能和燃油经济性能有着重要的影响。因此,研究平地机柴油发动机与液力变矩器的匹配是十分必要的。     

可替换连梁连接的双钢板混凝土联肢组合剪力墙抗震性能试验研究

为了研究可替换连梁连接的内填混凝土双钢板混凝土联肢组合剪力墙结构的抗震性能,进行了2层半单跨1∶3缩尺试件的低周反复加载试验。试验中对连梁进行了2次替换,分析了试件在循环荷载作用下的破坏机理、滞回性能、延性、刚度退化以及耗能能力。试验结果表明:水平荷载作用下,双钢板混凝土联肢组合剪力墙的可替换连梁首先进入塑性耗能,连梁替换后结构的抗震性能基本恢复到连梁替换前的性能水平;连梁端板没有出现变形,连梁拆卸和安装方便;设计中钢柱柱脚截面可适当加大,需合理设计柱脚部位的焊缝和连接构造,避免应力集中;可替换连梁连接的组合剪力墙结构的滞回曲线比较饱满,抗震性能较好;连梁替换前后结构的骨架曲线相差很小,其抗侧刚度基本一致;结构进入塑性后,试件的承载能力降低很小;在同水平荷载作用下,连梁的剪应力最大,边柱柱脚的正应力较大,中柱、钢梁及剪力墙钢板的应力较小。     

Identification of multiple criteria for the evaluation of light-frame wood wall assemblies

Design of light-frame wood wall assemblies should consider several performance criteria. Possible alternatives must respect minimum code requirements for the studied context. Then, additional performance characteristics may be considered to achieve the most suitable configuration for a specific project. It is, however, not simple to define how several performance criteria can be evaluated simultaneously and which scale should be used to compare assemblies. Existing tools to evaluate performance criteria consider mostly one parameter at the time. An evaluation methodology taking into account at once different performance characteristics would be beneficial in the decision process. With the final aim of developing a multi-criteria framework to support the evaluation of improved factory-built wood-frame exterior walls, this article presents a methodology for quantitative evaluation of a set of performance characteristics. The identification of appropriate criteria is followed by the choice of quantification mechanisms. A case study comparing five wall assemblies exemplifies this methodology.     

Using life cycle assessment to derive an environmental index for light-frame wood wall assemblies

Following a life cycle assessment (LCA) approach, this study aims at defining an appropriate performance index to consider environmental impact in the development of a multicriteria evaluation comparing factory-built wood-frame exterior walls. The investigation is applied to a case study comparing five wall assemblies for the exterior wall of a residential building in Quebec City (Canada). For the five alternatives, the life cycle inventory (LCI) provided by the ATHENA™ Environmental Impact Estimator software is aggregated using three different life cycle impact assessment (LCIA) methods: IMPACT 2002+, Eco-indicator 99 and TRACI. The relative impacts of assembly components and of the operation energy source on the environmental performance of the assemblies are investigated by comparing midpoint and endpoint indicators calculated with the three LCIA methods. The study concludes to the acceptability, in this specific context, of using the climate change indicator as an appropriate environmental index.     

Multicriteria decision analysis applied to the design of light-frame wood wall assemblies

Designers of light-frame wood wall assemblies should consider several performance criteria simultaneously in addition to minimum requirements set by building codes. Evaluation of various performance characteristics can help select the most suitable configuration for a given project in a given context. In a previous article, we identified appropriate criteria and explored their means of evaluation. Following up, this article integrates the context and the preference of the decision-maker and seeks to obtain a ranking of the various alternatives using quantitative and qualitative information. Four multicriteria decision analysis (MCDA) techniques are explored: weighted sum, MACBETH, ELECTRE II, and PROMETHEE. The approach is applied to a case study where five wall assemblies are compared within six different decision contexts. It shows how the choice of the appropriate aggregation method depends on the nature of the performance evaluation scales and demonstrates the usefulness of MCDA to consider simultaneously different aspects of wall performance.     

关于火灾隐患整改路径合理选定的思考

火灾隐患整改不能因为目标与方向正确,就忽视火灾隐患整改路径的选定;也不能因为整改路径存在问题而回避对火灾隐患整改的监督.科学、合理的火灾隐患整改路径能有效提高整改绩效,实现公安消防机构对社会公共消防安全的控制.     

型钢混凝土结构构造设计优化与建议

对型钢混凝土构造设计提出优化方案,指出优化设计应充分考虑柱—梁节点受力性能和方便施工;分析了全型钢混凝土框架体系的优越性;提出确定型钢混凝土构件合理含钢率的原则,以指导类似工程的设计。     

Fire endurance of lightweight wood trusses in building construction

Lightweight wood trusses are economical construction elements that combine high strength, light weight, and cost savings. The parallel-chord truss is one of the most common lightweight trusses used in commercial and residential occupancies today. Like all structural components, these trusses are arguably susceptible to failure when exposed to fire. This paper will address fire resistance concerns of parallel-chord, lightweight wood truss floor- and roof-ceiling assemblies, particularly their performance under fire conditions and their susceptibility to construction defects. Because evaluating the effect of fire exposure on both conventional and lightweight wood truss assemblies is so important, considerable supplemental background information on the standard fire test, as it applies to general types of construction, is also provided.     

Geocomposite edge drain joining

The integrity of the joints that connect all of the various components of a geocomposite edge drain system plays a significant role in the performance of the system. This paper reviews the need for edge drains, describes what they are and discusses the key performance requirements of the joints of an edge drain system. The geotextile seams, roll-to-roll splices and outlet system connections are the critical joints. These assemblies must remain sealed from soil infiltration and free of flow restrictions both after installation and throughout the edge drain systems' design life.     

细晶高强钢筋混凝土梁柱组合体抗震性能试验研究

通过对细晶高强钢筋进行的材性试验表明,细晶高强钢筋有很好的屈服台阶,属于一种强度高延性好的增强筋材。参照现行混凝土结构规范设计了4个不同配筋率的细晶高强钢筋混凝土梁柱十字型组合体,并对这些试件进行低周反复荷载试验。测试试件从开裂到破坏的全过程及最终破坏形态,并给出荷载-位移滞回曲线、开裂荷载、极限荷载等重要数据。对数据分析得到细晶高强钢筋混凝土梁柱十字型组合体抗震性能的延性指标和耗能指标。研究表明,采用细晶高强钢筋混凝土梁柱十字型组合体,具有较好的抗震性能和耗能性能。     

Experimental and numerical studies on the lateral performance of concrete sandwich walls

A series of quasi‐static tests was presented to study the lateral behavior of concrete sandwich walls and the precast concrete sandwich walls; the finite element analysis (FEA) models were built for numerical simulation of the specimens, and the parameters affecting the seismic performance of sandwich walls, and the precast sandwich walls were also analyzed based on the FEA models. The results show that the shear failure occurs in regular squat shear wall; the setting of the foam plate effectively reduces the stiffness and load capacity, and the reasonable design of sandwich region is conducive to the seismic performance. The responses obtained by the FEA models match well with the experimental results. The stiffness and load capacity of sandwich wall are increased, but the ductility is reduced when the axial load is increased; the deformation capacity can be greatly improved by increasing the aspect ratio but at the cost of load capacity and stiffness; the reasonable match of load capacity, stiffness, and ductility can be achieved by maintaining the appropriate length and thickness of the foam plate. The greater the friction force of CAF in the vertical seam of precast sandwich wall, the greater the load capacity and initial stiffness and the stronger the integrity of the jointed wall. When the strength of SRS in the horizontal seam is small, the concrete sandwich wall basically maintains elasticity; the deformation is mainly concentrated on SRS; when the strength of SRS is too large, SRS do not yield or the yield displacement is large, and the load capacity is mainly affected by the concrete sandwich wall.     

既有钢筋混凝土结构抗震设防目标与性能评估

以基于性能的抗震设计与评估理论为基础,考虑既有钢筋混凝土结构性能特点,结合我国现行抗震设计规范,对国内外规范及相关研究成果进行对比分析,给出既有建筑地震作用取值方法、抗震设防性能目标及性能指标的量化标准。给出既有建筑结构有限元分析模型的建立方法,形成较为系统的既有建筑抗震性能评价体系,其实用性及有效性通过对某一实际工程进行的抗震性能评估得以验证。分析结果表明：既有建筑结构抗震性能较拟建之初有明显降低,有必要建立既有建筑结构有限元分析模型。在进行抗震性能评估时,为获得较合理的评估结果,应根据后续使用期确定相应地震作用取值。结合给出的抗震性能目标、性能指标及其量化标准,该评价体系能够对既有钢筋混凝土结构进行合理、可靠的抗震性能评估。