制造安装误差对核电环行起重机定位精度的影响

以某型号核电环行起重机为研究对象,分析制造安装误差对其定位精度的影响。应用尺寸链的相关理论以及统计学的分析方法对在制造安装过程中影响起重机定位精度的各个因素进行了定量分析。通过计算,得到核电环行起重机各个部件的制造安装误差,并进一步分析其对定位精度的影响,校验设计的可行性,本文所做工作对产品设计更具有实际指导意义。     

建筑工程外窗副框安装施工技术探讨

建筑工程结构中的外窗副框安装施工技术是比较重要一个项目。外窗副框不仅关系到窗体的安全性,还决定了窗户的封闭性、灵活性等,应该规划好副框安装的过程,落实相关的施工技术,避免出现质量或性能问题,保障外窗副框安装的科学性。因此,本文重点分析建筑工程外窗副框安装的施工技术。     

圆弧等高齿弧齿锥齿轮的设计与性能分析

为了改善齿轮副的对角接触现象,将常规弧齿锥齿轮的渐缩齿改为等高齿齿形,采用0号刀齿铣齿,从理论上避免对角接触。基于齿轮的局部啮合原理、齿面接触分析(TCA)技术和承载齿面接触分析(LTCA)技术,对相同条件下等高齿设计与常规齿轮设计的实际接触区、载荷及应力应变进行了分析。分析与加工试验结果表明:理论与实际接触区位置基本相同,所受力的大小以及应力分布也基本相同。与传统的齿轮设计相比,等高齿弧齿锥齿轮设计保证了齿轮强度、齿轮啮合质量,使其接触区规范且易于调整,有利于提高加工效率。     

提高电缆安装性能的关键在哪儿？

在综合布线的施工安装中．人们通常会认为安装的正确与否是提高电缆安装后性能的重要原因，然而，即使在正确安装的情况下．某些设计出来的能够在电缆盘上提供高电气性能的电缆在实际安装时却不能获得同样的性能等级。越来越多的厂家已经意识到，需要设计一种电缆,无论是在电缆盘上还是在实际的使用中，都能够为用户提供优异的电气性能。Belden IBDN粘连线对电缆可以说是满足布线安装市场需求的典型产品。     

装配误差对山岭隧道装配式衬砌受力性能的影响

为研究装配误差对山岭隧道装配式衬砌受力性能的影响,文中以广东省某公路隧道为依托,通过采用荷载结构法分析了不同形式和不同大小装配误差对山岭隧道装配式衬砌受力性能的影响,研究结果表明,对装配式衬砌来说,最不利受力工况发生在装配式衬砌和底座的装配过程中;装配误差主要影响衬砌装配成功与否,装配完成后的衬砌与正常装配的衬砌受力性能差别不大。     

齿轮轮齿表面粗糙度的确定

齿轮齿面的粗糙度，对齿轮的强度影响较大。本文讨论了齿轮面粗糙度，对齿面抗胶合能力和齿面强度的影响，齿面粗糙度的计算方法，并举例进行了计算说明。     

剃齿前径向误差对剃齿后切向误差的影响

通过对齿轮滚齿时产生的径向误差Fr对剃齿切向误差Fw影响的分析，得出一个结论，即现场生产中必须加强剃齿前滚齿径向误差Fr的控制，从而提高齿轮剃齿精度。     

大型齿轮的失效和维护

运用材料力学和磨擦学理论对大型齿轮的失效形式即过载失效和过度磨损进行分析,得出了失效产生的原因,表面接触应力过大,齿面硬度低,油温过高,油品清洁性不好等,从失效产生的原因针对性逐项提出了实际生产中防止失效的维护与保养方法,从而对提高齿轮寿命。作出了有益见解。     

Human error in the management of building projects

This paper seeks to improve the understanding of human error as it is applied to the generation of defects in construction projects. It reviews the literature concerning human error, commencing at the psychological basis of errors. From this, the review is expanded to include literature from forensic engineering, industrial safety, reliability engineering, sociology and quality management. Based on the literature, a model of the factors influencing the incidence of errors in project based industries is constructed. This model proposes that errors leading to defects and more dramatic failures can be generated from all levels of project organizations. They stem from primary factors (related to the performance of the individual), management factors (related to a range of managerial tasks) and global factors (related to wider external influences). These factors can be displayed as a hierarchy with primary factors at the base and global factors at the top. The paper reports on the results of an initial test of this model by reference to a survey of a sample of construction industry practitioners. The findings of the survey support the model, with some modifications. Additionally, some differences in view were noted: in particular, respondents from a construction background emphasized managerial factors more strongly than those from a design background.     

如何提高真空挤出机减速器齿轮的可靠性

真空挤出机的减速器是主要的传动系统,一直是决定真空挤出机可靠性的关键环节。为此从合理设计传动结构,齿面硬度组合的选择和硬齿面-中硬齿面齿轮的制作三个方面论述了提高真空挤出机减速器齿轮可靠性的措施。     

基于稳健估计的GPS高程拟合

为了研究稳健估计法在GPS高程拟合中的抗差能力,通过模拟在已知点中分别加入0．05m、0．1m、0．2m和0．3m的粗差以及在两个已知点中加入粗差,并采用二次曲面拟合法、BP神经网络模型和基于Huber法定权的稳健估计法进行对比。计算结果表明,稳健估计法应用于GPS高程拟合具有较好的抗差能力。     

新型干法水泥熟料节能减排技术集成示范应用研究

对两档短窑从项目设计的优化、工艺参数的匹配、单体技术在生产线中的稳定性、可靠性、对工艺的调试、成果的汇总展示等方面,研究新型干法水泥熟料生产集成技术最佳的工况指标,实现最佳节能减排效果,达到对水泥工业技术进步和节能减排的引领示范作用。     

齿轮齿条式电涡流阻尼器的力学性能研究

为开发性能良好的新型耗能装置,采用齿条齿轮和电涡流阻尼技术,提出一种新型的齿轮齿条式电涡流阻尼器(eddy current damping-rack and gear damper,简称ECD-RGD),并对其力学性能进行有限元仿真和试验研究。首先,介绍ECD-RGD的构造和运动分解,并设计制作ECD-RGD样机;然后,考虑两个加载角度研究ECD-RGD的表观质量和阻尼性能;最后,对ECD-RGD的滞回性能进行试验研究。结果表明：ECD-RGD是一种实现表观质量惯性力和电涡流阻尼力并联的新型阻尼器,可将结构振动的随机方向分解为确定的相互垂直的两方向加以控制;表观质量的理论结果与试验结果、电涡流阻尼力的仿真结果与试验结果总体吻合均较好;样机试验性能稳定,齿轮齿条式电涡流阻尼器具有可应用性。     

焦作市GPS高程拟合模型优选研究

以焦作市为倒,分别利用平面相关拟合法、二次曲面拟合法和多面函数法进行GPS高程拟合研究,通过试验发现多面函数法的拟合精度要优于其他两种方法,最后给出了有益的结论。     

Optimal mixing ratio and SWCC fitting of lightweight soil with cotton stalk fibres

The application of lightweight soil for changing and filling is an effective foundation treatment method for the construction of sponge cities in collapsible loess areas. In this paper, the L₂₅(5⁴) orthogonal test targeting on the strength, permeability and density characteristics was first used to optimize the mixture ratio design of proposed lightweight soil with cotton stalk fibres (LSCF). The corresponding effects of each mixed content on the performance of LSCF were analysed. The soil water characteristic curves (SWCCs) of LSCF with different cement and cotton stalk fibre contents were then measured using the quick centrifuge method. In comparison with undisturbed loess, the volumetric moisture content of LSCF (for the same matrix suction) was larger, and LSCF had a better water-holding capacity. Based on the Van Genuchten model, an improved fitting model for matrix suction SWCC of LSCF was proposed by considering the influence of cement. Qualitative agreement with the test results indicates that the proposed model could be potentially used to obtain the SWCC curve without conducting any experiments, which is especially useful for the sponge city constructions in loess areas.