浅谈顶盖横梁拼焊工艺优化及其模块化定位的工作方法

本文通过对产销量大的低配车型顶盖合拼的工艺优化,对前横梁、中横梁和后横梁的上件工艺方案及其定位夹具优化,开发新一代中横梁、后横梁的定位夹具,将中横梁、前横梁等零件的定位方法模块化,形成一种整体解决方案,具有较高的应用推广价值。     

船舶柴油机大气污染物排放特性及控制技术研究现状

  目的  船舶柴油机选择性催化还原（SCR）反应器的NOx转换效率受其入口流场均匀性的影响。为优化柴油机排气管路设计,提高其转换效率,有必要建立合理的入口流场均匀性评价体系。  方法  以某船用柴油机排气管路为研究对象,首先,在额定工况下对其流动特性进行分析;然后,在此基础上进一步通过引入多项评价指标,从不同的角度对SCR反应器入口流场均匀性进行评估,并对各评价指标之间的差异性与适用性进行探讨。  结果  结果表明,管道弯折、突变部位的压力损失约占排气系统的20%,且SCR反应器入口前的弯折对其入口流场均匀性的影响较大,局部最大不均匀度高达19.96%。  结论  研究显示,为提高入口流场均匀性,SCR反应器入口面应与弯折、突变部位保持一定的距离;对于船用柴油机排气系统,均匀性指数γ值和局部面积最大不均匀度δ更能切实地评价SCR反应器入口流场均匀性。研究结果可为合理评估流场均匀性提供重要参考依据。     

舰船的电化学腐蚀及其外加电流阴极保护法应用状况

  目的  舰船材料的腐蚀不仅影响舰船航行安全、降低舰船服役期限,而且还会造成维修负担、产生高额的维修费用,因此进行舰船材料防腐研究,设计新型舰船材料防腐剂具有重要的科学价值和现实意义。  方法  总结现有舰船材料防腐手段存在的问题,提出石墨烯防腐涂料的结构特性及其在舰船材料防腐领域的应用前景。然而,石墨烯涂层由于自身结构缺陷及其与基体耦合作用弱等因素,会导致其与基体在长期作用时出现加速金属腐蚀的现象。针对这一问题,总结出功能化处理石墨烯的方法,将功能化石墨烯与基体复合,得到改性石墨烯/聚合物复合材料并对其进行电化学测试。  结果  结果表明,经过功能化处理的石墨烯在一定程度上能提高涂层的防腐性能。  结论  结合当前舰船材料防腐涂料的研究进展和趋势,可为石墨烯防腐涂料在舰船材料防腐领域的应用提供理论基础。     

舰用IGBT模块国产化必要性及路径综述

本文系统论述了国内外IGBT模块的研究现状,具体分析了舰用IGBT模块国产化必要性和发展路径,并对相关关键技术研究提出了发展思路,为后续开展国产化研制奠定了基础。     

公路隧道火烧应急检测

火烧是目前公路隧道常见事故之一, 由于隧道结构狭长、 空间小、 通风条件差等特点一直是应急检测的难点。 文章以火场温度分析为基础, 依托实际工程, 阐明火烧应急检测内容, 为养护决策提供依据。     

Numerical method of electromagnetic pulse response of conductor with complex load北大核心CSCD

[Objectives]Electromagnetic pulse can seriously affect and even destroy naval shipborne electronic information systems, weapons, equipment and so on. Due to the complexity of the antenna port load circuit, it is necessary to formulate a numerical method which can easily obtain the antenna load current. [Methods]The induced current of the terminal is obtained on the basis of the finite-difference time-domain (FDTD) and Holland model. According to the Thévenin equivalent circuit, the conductor is equivalent to the voltage source to realize decoupling between the conductor and load end, and the load circuit is solved using Simulink software.[Results]Compared with the traditional terminal model, this method is simple and feasible for high-order circuit processing. The effectiveness of the model is verified using non-linear elements and parallel capacitors and resistors as the load respectively. The results show that the calculation results of this method are consistent with those of the traditional methods. Finally, the antenna of the end-connected protect- or is calculated. The results show that the lead inductance caused by the installation of the protector is an important factor affecting the protection performance.[Conclusions]The method proposed in this paper can greatly reduce the simulation complexity of the coupling current of an antenna with a complex load, giving it useful reference value for the field of ship electromagnetic pulse protection design. © 2023 Editorial Department of Chinese Journal of Ship Research. All Rights Reserved.