大型集装箱船高强度厚钢甲板安全寿命评估方法

疲劳是船舶与海洋工程结构破坏的主要模式之一.高强度钢的应用使得结构的疲劳问题更加突出.对于采用以高强度厚钢板为甲板的大型集装箱船来说,有必要进行高强度厚钢板的焊接缺陷部位安全寿命评估方法研究.以应力范围的长期分布服从两参数Weibull分布的随机载荷为疲劳载荷,裂纹扩展率采用单一曲线模型预报裂纹在任意时刻的尺寸,结合应力强度因子并参考应力计算方法和失效评估图技术提出一套计算集装箱船高强度钢厚钢板安全寿命评估的方法.通过编制计算程序,对某集装箱船甲板进行安全寿命计算.最后,分析疲劳载荷谱对安全寿命的影响.计算结果表明：载荷回复期的长短和Weibull分布的形状参数的取值都会极大影响结构疲劳安全寿命.     

A detailed finite element investigation of the effects of local lateral high-velocity impacts on the ultimate strength of unstiffened steel plates subjected to uniaxial in-plane compression

In this paper, the ultimate strength of unstiffened steel plates under uniaxial in-plane compression is numerically studied considering the local lateral impact of a rigid-body impactor. The plates are made of mild steel, where its behaviour is modelled by using the Johnson-Cook material model. The material parameters of the Johnson-Cook material model calibrated by the authors were employed for predicting the behaviour of the target in order to numerically reproduce the impact tests. The value of average in-plane stress of the plates is determined accounting for the collision of rigid-body impactor with masses of 50–150 gr and velocities of 400–1200 m/s. Moreover, the effects of stress waves induced as a result of lateral impact of the rigid-body impactor on the ultimate strength of the plates under uniaxial in-plane compression are also assessed. The results indicate that the ultimate strength of the plate decreases due to stress-wave creation and thus, it is required to take that into account. Besides, it is revealed that assuming the final damaged state of the plate after being laterally impacted by the rigid-body impactor as an initial condition, does not yield a correct response when evaluating its ultimate compressive strength under uniaxial in-plane compression.     

京新高速钢板组合梁桥工字钢梁温度效应研究

温度效应是影响桥梁内力、线形乃至施工安全的重要因素。本文以盆克特2号钢板组合梁桥为例,以板单化规律进行研究;据此规律,重点分析支座与跨中两个关键截面温度梯度作用下截面正应力随梁高的变化规律;按照中、英、美三国规范分别规定的温度梯度作用建立模型,对工字钢梁跨中截面应力分布特征进行对比分析。     

严寒地区无砟轨道底座板混凝土粉化整治技术

严寒地区无砟轨道底座板混凝土粉化病害已威胁到列车行车安全,须及时整治。本文阐明了严寒地区底座板混凝土粉化主要原因是混凝土抗冻性不足、无砟轨道结构排水不畅及冻融温度过低。根据底座板混凝土粉化的程度,提出了合理有效的整治技术,包括方法、材料和工艺。经对哈大客运专线60 m长底座板混凝土严重粉化试验段整治发现,填充防护层对底座板防护效果良好,其与底座板形成的叠层修复结构状态稳定。     

钢板剪力墙钢结构变形控制措施研究

钢板剪力墙结构体系作为新型抗侧力构件被应用到工程施工中,具有结构自重轻、施工速度快、抗震性能好、节约建筑空间等优点。本文结合萧政储出40号地块1标段塔楼钢板剪力墙施工实例,对钢板剪力墙产生变形的原因进行研究,最终采用缩短竖向安装单元尺寸、工厂整体制作安装单元、水平焊缝影响区设置加强角钢、相邻钢板墙之间设置工艺梁等措施,解决了导致剪力墙钢结构安装变形的主要问题,使钢板剪力墙钢结构安装偏差从根本上得到改善,并且平均每层缩短工期5 d。     

铝合金蜂窝板钎焊接头的超声波C扫描检测

分析了铝合金蜂窝板钎焊接头连接状态与超声检测C扫描信号的关系,建立了钎焊接头有效连接面积的超声检测分析模型,并基于该模型生成C扫描图像。利用图像增强、边缘检测等图像处理方法对C扫描图像进行处理,处理后的图像能够清晰地显示出钎焊接头形貌。将钎焊接头尺寸的实际测量值与超声检测值进行对比,结果表明,超声检测所得焊缝有效连接面积与实测值绝对误差小于0.11 mm,证实了超声波检测可用于铝合金蜂窝板钎焊连接面积定量分析。     

时速160 km城市轨道交通预制板整体道床设计与施工

北京新机场线是我国首条设计时速为160 km的城市轨道交通线,其运行速度远高于一般城市轨道交通线路。因此,需对其道床结构进行重新设计。在高速铁路CRTSⅢ型板式轨道的基础上,结合新机场线的线形特征、环境特点和施工技术,提出在正线中有较大沉降危险性的区域采用普通型预制板整体道床,在地下线中部分有减振要求的地段采用减振垫浮置板道床(预制板式)的设计方案,并对新机场线几种预制板整体道床设计方案、结构组成进行了阐述,对其施工流程和施工工艺进行了详细介绍。     

动车组车轴防尘座板与轴承后挡圈检修分析及优化

统计CRH380A(L)和CRH380A型动车组的新/旧轴箱轴承后挡圈内径和新/旧车轴防尘板座外径尺寸,以分析车轴报废比例和报废原因。对统计数据进行概率分析,得到轴箱轴承每次检修退卸后的防尘板座外径尺寸的减少量;对现有检修标准和后挡圈与防尘板座配合过盈量进行分析,提出防尘板座尺寸公差标准的优化方案;根据车轴报废比例和报废原因,得出标准优化后每年检修成本的节约量。通过寿命和成本分析,验证对现有标准进行优化的必要性。     

钢桥板式加劲肋局部稳定试验与设计方法研究

板式加劲肋是钢结构桥梁中钢箱、钢塔以及钢拱等结构的基本组成板件,板式加劲肋的局部失稳是其主要的失稳破坏模式。为研究板式加劲肋的局部稳定性能,分别设计了变化板肋厚度与宽度2组板肋局部稳定试件进行轴压试验,并建立相应的有限元分析模型,计入本构关系、残余应力与局部初始几何缺陷对局部稳定性能的影响,得到板式加劲肋与三边简支板的局部稳定简化计算公式。试验与分析结果表明:①当板肋宽厚比小于16时,出现板肋与被加劲板的同时屈曲破坏,反之,则仅出现板肋的局部失稳破坏;②随着板肋宽厚比的增大,试件发生破坏时的失稳变形现象越来越明显,对于变板肋厚度试件,试件极限平均应力随着板肋宽厚比的增大,呈先增大后减小的趋势,对于变板肋宽度试件,极限平均应力随着板肋宽厚比的增大逐步递减;③当相对宽厚比大于0.91时,采用板肋加劲板构件中的板肋所拟合的三次多项式曲线高于其他规范曲线,当相对宽厚比小于0.95时,三边简支一边自由的简化模型所拟合的公式曲线与GB 50017-2017规范曲线、Eurocode 3曲线以及美国AISI规范曲线较为接近,在整个相对宽厚比范围内均高于中国钢桥规范与日本规范曲线;④采用构件中板式加劲肋拟合的公式可以更好地计算实际试件承载力,采用三边简支一边自由的简化模型拟合的公式则更安全,推荐采用三边简支板拟合公式进行计算。     

Plastic deformation of ship plate subjected to repeated patch loads at different locations - Elastoplastic numerical analysis and design equation

Ship structures may be subjected to repeated random patch loads at different locations. Under these circumstances, ship plates will have large accumulated permanent deformations, which will result in some serious negative effects on their work and safety performance. Therefore, the elasto-plastic response of ship structure under repeated patch loads at different locations are studied by using finite element method. The permanent deformations of plate in the whole loading and unloading process are investigated. In addition, the residual stress and plastic strain states of the panel and stiffeners are studied based on a typical wheel-on-deck interaction scenario. Moreover, according to Hughes's hypothesis, the equivalent method between repeated patch loads at different locations and full uniform pressure load is studied. Considered the influence of plate slenderness, the improved formula for equivalent load coefficient is proposed, showing a good correlation with experimental data and numerical results. The proposed equivalent method can be used for estimating the permanent deformations of ship structures under repeated patch loads at different locations in ship life.