最小二乘平差在纸海图矢量化过程中的应用

在矢量化纸海图时,由于基准点的采样误差,导致转换参数的误差,最终导致电子海图的空间对象的精度不高。本文应用最小二乘法对基准点的采样误差实施平差,提高转换参数的精度,最终可较大幅度地提高电子海图中空间对象的精度     

钢丝绳失效机理分析及改进举措

微动疲劳与腐蚀疲劳是造成钢丝绳失效的主要原因。选用纯净度高的帘线钢盘条为原料制造钢丝绳,并对制绳钢丝进行表面处理,提高钢丝的防腐蚀、耐磨损性能,同时通过改进设备和工艺提高捻制质量,可大幅度地提高钢丝绳的质量和使用寿命。光面钢丝绳或将被淘汰。     

Corrosion rate measurements in steel sheet pile walls in a marine environment

Corrosion of steel structures in the marine environment is a major problem. The deterioration of this kind of structures is costly and difficult to predict both when designing new structures and when estimating the remaining service life time for existing structures. The aim of this investigation was to find indicative values for the corrosion rate of steel sheet piles on the Swedish west coast. Such corrosion rates (mm/year) can be used both when designing new structures by oversizing the steel thickness and when estimating the bearing capacity of existing sheet pile structures. Earlier investigations on the corrosion rates along the Swedish east coast – with salinity from about 0.2% to 0.8% – are still used today as guidelines for the corrosion rate of all steel structures in the Swedish maritime environment even though the salinity on the west coast can be as high as 3.0%.Steel sheet pile wharfs located in the port of Halmstad on the Swedish west coast were inspected by ultrasonic measurements. Three wharf structures with a total length of about 700 m were inspected. None of the inspected wharfs had or have had cathodic protection. The thickness measurements of the steel sheet pile structures were performed by divers.The age of the three inspected sheet pile structures ranged from 36 to 51 years. The dimensions of the original sheet pile sections are known. One of the quay structures is located along a river. The salinity at all wharfs varied from low values at the surface to approx. 2% at the bottom (also in the river outflow).The measured average corrosion rates were in the same order as the design values in the European code. However, the results indicate increased corrosion rates about 1 m below the mean water surface and at the level of the propellers from the ships berthing the most frequented of the inspected wharfs, 3–6 m below water surface.The tolerances of steel sheet thicknesses – usually in the order of ±6% – are often neglected when investigating the remaining thickness in steel sheet piles. A simple calculation model shows that the sheet pile must be almost 50 years of age before an accurate estimation on the corrosion rate can be made, considering the tolerances, if the true original sheet pile thickness is not known.     

锈蚀钢筋混凝土梁抗弯承载力计算及破坏截面预测

通过锈蚀钢筋混凝土梁抗弯承载力试验,在已经提出的基于锈胀裂缝宽度的锈蚀率计算方法基础上,根据承载力试验结果建立了基于计算锈蚀率的锈蚀梁承载力计算方法,同时提出了锈蚀梁危险截面位置的预测方法,与已有研究成果的对比表明,该方法具有良好的准确性和实用性,可以为锈蚀梁残余承载力和危险截面的预测提供参考。     

CT扫描技术在混凝土结构检测中的应用

为了解CT扫描技术在工程检测应用中的可行性及优越性,特别选取预制典型裂缝、疲劳加载、锈胀裂缝及现场混凝土构件,对其进行CT扫描室内试验,获得构件典型病害CT图像。试验分析表明:CT扫描成像能直观体现混凝土内部的缺陷和破损情况,并能对缺陷和破损进行定量分析,可见该检测技术应用效果良好。随着CT扫描仪器的发展,便携式CT将成为可能,CT扫描技术在混凝土结构检测中必将占有重要的地位。     

62310轴承故障的应对方法

以DK16A地铁电动车辆牵引电机62310轴承故障为例,分析了故障成因,并对相应的措施进行了论述。     

阴极保护30年码头钢板桩腐蚀状况

钢板桩入海35年,阴极保护运行30年。未发现板桩有腐蚀穿孔、腐蚀破损等现象,平均腐蚀减薄0.84 mm,平均蚀余厚度是原始厚度的95%;腐蚀减薄从大到小依次为水位变动区、浅水区、水中区和泥面区,泊位中段一根凸桩浅水区位置的减薄最大,为2.60 mm;凸桩和凹桩的平均蚀余厚度相差不大,凸桩不均匀腐蚀大于凹桩。阴极保护有效地抑制了海水对钢板桩的腐蚀。     

船体结构腐蚀疲劳问题以及数值计算方法

船体或者内部高强脆性材料在腐蚀环境中的破坏问题已受广泛关注,其中涉及破坏机理的研究屡见报道,但相关的数值计算研究方法目前还屈指可数,文章在介绍各种破坏机理的基础上,从数值计算方法研究的角度阐述了最近几十年中的研究进展以及作者在该领域所取得的前沿性的成果,并指出了无网格有限元计算方法将在这个研究领域扮演重要角色.     

基于灰色马尔可夫理论的油气管道腐蚀剩余寿命预测

以灰色理论的标准GM（1,1）模型和马尔可夫TPM理论为基础,提出了基于灰色马尔可夫理论的油气管道腐蚀剩余寿命预测方法。利用灰色马尔可夫理论预测腐蚀油气管道剩余寿命的步骤主要包括：最大允许腐蚀深度的确定,腐蚀速率的预测以及剩余寿命预测。并基于该方法,采用VB系统开发了实用软件,简便可靠。该方法可以在腐蚀速率波动比较大的情况下预测油气管道的剩余寿命,为油气管道腐蚀检测周期的确定提供了科学依据。     

城市燃气管道腐蚀综合检测方法

针对城市燃气管道腐蚀的主要影响因素,分析现有的各种检测方法的技术原理和应用条件,提出了一个科学、合理、全面的城市埋地钢质燃气管道腐蚀检测流程,这对于城市燃气管道的安全运行有着重要的作用和意义.