电沉积法修补混凝土裂缝技术

裂缝对混凝土耐久性具有重要的影响。电沉积是一种有潜力的混凝土裂缝修补方法,但要发展成为一种成熟、实用的技术尚有许多问题亟待解决。对电沉积方法修补混凝土裂缝的技术参数进行研究。结果表明在硝酸镁(Mg(NO3)2)溶液中,以0.5 Am2电流密度进行电沉积的修复效果较好,修复后试件抗压性能得到提高。     

Geometry modeling of ship hull based on non-uniform B-spline

In order to generate the three-dimensional (3-D) hull surface accurately and smoothly, a mixed method which is made up of non-uniform B-spline together with an iterative procedure was developed. By using the iterative method the data points on each section curve are calculated and the generalized waterlines and transverse section curves are determined. Then using the non-uniform B-spline expression, the control vertex net of the hull is calculated based on the generalized waterlines and section curves. A ship with tunnel stern was taken as test case. The numerical results prove that the proposed approach for geometry modeling of 3-D ship hull surface is accurate and effective.     

有效应力强度因子范围门槛值与载荷比关系的研究

不同载荷比下的有效应力强度因子范围门槛值△Keff.th往往被看作一个常数,然而疲劳实验数据结果通常散落在一个较窄的带宽范围内,而不是所期望的一条曲线。另外,基于改进的McEvily模型对△Keff.th进行的灵敏度分析表明△Keff.th对疲劳裂纹扩展率具有重要的影响,尤其是在占有大部分疲劳裂纹扩展寿命的近门槛值区域。因此,文章认为不同应力比下的△Keff.th为变量,并且通过三个方面对△Keff.th与应力比R的关系进行了深入的研究:(a)Schmidt和Paris提出的一个关于△Keff.th的简化模型和相应的试验数据;(b)基于传统的裂纹完全闭合概念的△Keff.th试验数据;(c)基于裂纹局部闭合模型的△Keff.th,p试验数据。分析结果表明,在应力比低于临界应力比时,随着应力比的增加,有效应力强度因子范围门槛值也相应增加;而应力比高于临界应力比时,有效应力强度因子范围门槛值随应力比的增加而减小。另外,通过对试验数据的曲线拟合分析表明,Lorentz分布能很好地描述相应的试验数据。     

某围海造地项目堵口合龙方案研究

在围海造地过程中必然要面临堵口合龙问题,堵口合龙时口门处的水力条件非常复杂,对堵口工程的安全稳定性影响很大,传统简易的设计、施工方法难以有效解决该问题。以某围海造地项目为例,介绍了该项目的龙口水力计算情况,并对堵口合龙过程中口门处的水动力情况进行分析,选择合适的口门位置和尺度,合理安排堵口施工程序,为堵口合龙施工提供了科学依据。     

用EXCEL进行太阳真方位计算

文章介绍了运用EXCEL软件计算太阳真方位及太阳的磁影方位,并给出了计算的具体操作程序和解释。     

汽车电子系统的检修步骤

通过对别克君威轿车冷却风扇不转引起发动机开锅故障的诊断与排除,探讨在电子器件修理中如何正确识读汽车电路图、找出关键点、理顺检修思路,利用自身现有的检测设备,从不同的角度来论证电子器件的性能,从而正确快速地检修电子器件。     

原油转驳船主推进器基座设计制造与安装技术

针对原油转驳船（Cargo Transfer Vessel，CTV）主推进器设备尺寸大、质量大和安装难度大等问题，设置主推进器基座，用于对艉部结构与主推进器的连接安装。详细研究主推进器基座的设计、制造与安装技术。对主推进器基座进行合理的结构设计，确定有效的焊接工艺和安装流程，可确保基座的结构稳定性和制造与安装的精度。     

Development of a retrofit layer with an embedded array of piezoelectric sensors for transient pressure measurement in maritime applications

Measurement of transient pressure distribution on maritime structures is important for the assessment of the hydrodynamic loads applied. The commonly used pressure sensors are mostly bulky, need to be bolted to the structure, and/or only provide point-wise measurements. In this paper, an elastic matrix layer with a network of embedded piezoelectric sensors is proposed to address these issues. For experimental validation, a 400 × 400 × 5 mm epoxy layer is fabricated embedding 25 piezoelectric sensors on a square grid in accordance with Gauss-Lobatto-Legendre points. A finite element based inverse procedure is developed to reconstruct the pressure field from the electric potentials measured by the piezoelectric transducers. Feasibility of the concept is evaluated by measuring and reconstructing the pressure field generated by a travelling wave in a water tank. Sensitivity of the layer is also investigated through the experiments. The results indicate that the retrofit layer is capable of pressure field reconstruction, and that the presence of disturbances on the sensing surface does not affect the measurements in a notable way, while non-ideal conditions of the mounting can have a significant impact on the accuracy of the measurements. The results highlight the potential of the concept in pressure distribution measurements.     

极地船用FH40低温高强钢焊接工艺

以不同厚度规格的极地船用FH40低温高强钢为研究对象，分别采用焊条电弧焊（Shielded Metal Arc Welding，SMAW）、CO2气体保护药芯焊丝电弧焊（CO2 Gas Shielded Flux-Cored Arc Welding，FCAW-CO2）、埋弧焊（Submerged Arc Welding，SAW）等3种方法进行工艺试验。结果表明：焊接接头符合相应规范要求，力学性能指标符合设计要求。试验确定的焊接工艺参数可为新型极地船建造提供指导。     

不间断运营的地下通道改扩建技术研究

以浦东机场进场路地道改建工程为例，重点对为满足地下道路不间断运营工况的地道结构进行受力分析及施工步序研究。解决了传统地下通道改扩建工程需要封闭地下道路交通的难题，即整个施工期间地下交通仍能不间断运营。方案在国内尚属首例，具有标志性意义。