世界及我国船用低速柴油机行业发展研究

文章介绍了世界和我国船用低速柴油机行业的市场规模和竞争格局,分析了我国船用低速柴油机行业在产业集中度、二轮配套能力、自主创新能力和组织管理等方面存在的问题,并就如何提升行业竞争力,给出加大核心配套能力建设、加大高端产品的引进消化吸收等几点建议。     

Experimental investigation of structural system capacity with multiple fatigue cracks

Few experimental data sets exist in the literature to support the development and evaluation of digital twins predicting structural degradation. The literature is especially sparse for system tests where multiple failures occur and interact. In this work, a laboratory-level experiment is conducted to mimic many of the properties of larger and more complex marine structures with redundant load paths, failure interaction, and component-to-system level integration. In the experiment, such properties are reflected by a hexagon tension specimen with four propagating fatigue cracks tested under displacement-controlled loading. The applied loading cycles and corresponding crack lengths are recorded as the major time-varying data of degradation, with the resisting force at maximum extension used as the system capacity. A novel computer vision method is used to measure the crack length. Strain gauges are also used to monitor the structure’s status. The experimental data is presented and analyzed in this paper. The resulting data sets can be used to evaluate the performance of different digital twin updating approaches.     

基于STAR-CCM 的多功能工作艇阻力计算方法研究

本文基于STAR-CCM+,运用平均雷诺数方程和Realizable 湍流模型,对一条宽船型、带有非流线型顶推装置的多功能工作艇的实船模型进行阻力性能预报,将计算的静水阻力与船模试验结果进行对比分析,计算值与实验值吻合良好,并给出了船体周围的流场信息。分析了多功能艇的特殊装置——顶推装置对船舶阻力的影响,发现在低航速时,顶推装置对于剩余阻力的影响较明显,为该船型的快速性优化提供参考依据。     

中间渠道交汇区尺度及船舶航行方式研究*

利用自航船模试验,研究两级单线航道中间渠道供船舶交汇错船的交汇区尺度及船舶航行方式。试验表明,中间渠道交汇区通过斜导墙缩窄分别与上、下游通航建筑物连接,过渡段长度大于2倍船长是合理的。参考相关标准和设计规范确定交汇区宽度和船舶航行方式,确保一线船舶停泊另一线船舶以正常航速航行能在交汇区顺利进行交汇,以提高通航建筑物通过能力和船舶航行安全性。     

混凝土的剥蚀与破坏

建筑物的设计使用年限是根据工程的实际需求而确定的。某高速公路设计使用年限为100a,但是工程尚未竣工,在特大桥、中桥和互通立交桥的墩台身、盖梁混凝土部位出现了严重的混凝土剥蚀现象。通过工程的实际调查及现场取样分析表明,引起混凝土劣化的原因是粗骨料的石粉含量、混凝土掺入硅灰后没有采取更好的养护措施,加上重度盐雾区氯盐的影响,加快了混凝土劣化现象。因此,必须引起设计和施工单位的重视。     

江海直达驳的实船营运试验分析

该文就江海直达驳矿石运输系统的可行性,以实船作营运模拟试验,从试验结果的分析中提出了开发江海直达驳船型等应注意的问题。     

检测仪在起重机防风能力检测中的应用

一种根据自锁原理设计的新型检测仪,用于检测港口轨道式大型起重机的防风制动能力,以作出其是否达到国家标准的判定.该检测仪依靠特殊设计的机构,可快速固定在起重机轨道上,通过液压缸推动被检起重机从静到动,用计算机记录压力曲线,以获得最大制动力.     

Investigation of acoustic scale effects and boundary effects for the similitude model of underwater complex shell-structure

In this paper, the acoustic scale effects and boundary effects for the similitude model of underwater complex shell-structure are investigated. The similitude conditions and relations between the similitude model and its prototype were studied in the references. This paper investigates the acoustic scale effects for the similitude model, which are influenced by loss factor, shear and rotatory inertia. At the same time, the boundary effects which are influenced by surface sound reflection are investigated in the experiment of similitude model. The results show that the acoustic scale effects may be controlled with model designing, the boundary effects can be controlled with experimental designing between the similitude model and its prototype.     

小尺度船模Z型试验数据的计算机分析

用小尺度船模研究内河通航问题,是当今航道整治研究中采用的一项先进技术,为了保证船模试验研究质量必须经常进行船模操纵性能率定,率定试验的组次常常高达数十组至数百组,这就使试验的后期分析工作量很大.以前分析都是用人工完成,效率低,精度差,而且容易产生误差.为此,需要采用计算机代替人工对Z形试验数据进行分析,以提高率定试验的精度和速度,从而保证船模试验研究成果的质量.     

论资产经营在企业结构中的作用

本文分析和阐述资产经营的概念、模式及其在企业结构调整与规模扩大张中的作用,并结合我国汽车行业企业集团发展现状,探讨和提出了运用资产经营手段实施结构调整和规模扩张的具体方式和途径。