由圆环板正交连接的双层变厚度带肋圆柱壳整体结构矩阵分析

利用圆环板与内、外圆柱壳正交连接的变形协调条件,把每跨双层壳作为整体,建立双层 圆柱壳段的平衡方程,并叠加环肋骨、中间支骨、纵筋的刚度。运用相关矩阵分析手段和相邻 壳段的连续条件,将壳段平衡方程组集成待定参数的总体方程。该方法可以准确求解双层圆 柱壳结构任何部位、构件的挠度和应力     

Propagating buckles in corroded pipelines

Rigid–plastic solutions for the steady-state, quasi-static buckle propagation pressure in corroded pipelines are derived and compared to finite element predictions (ABAQUS). The corroded pipeline is modeled as an infinitely long, cylindrical shell with a section of reduced thickness that is used to describe the corrosion. A five plastic hinge mechanism is used to describe plastic collapse of the corroded pipeline. Closed-form expressions are given for the buckle propagation pressure as a function of the amount of corrosion in an X77 steel pipeline. Buckles that propagate down the pipeline are caused by either global or snap-through buckling, depending on the amount of corrosion. Global buckling occurs when the angular extent of the corrosion is greater than 90°. When the angular extent is less than 90° and the corrosion is severe, snap-through buckling takes place. The buckle propagation pressure and the corresponding collapse modes also compare well to finite element predictions.     

Influence of the design constraints on the thickness optimization of glass panes to achieve lightweight insulating glass units in cruise ships

The increasing complexity and size in cruise ships demands for lightweight structures and practical but accurate design methods. Conventionally, the focus has been on the steel parts of the ship, as they make most of its weight. However, the proportions of other materials are increasing. Therefore, this study attempts to provide better understanding how one could reach the lightweight designs of insulating glass units (IGUs) in ships. These are windows where at least two glass panes are separated by a hermetically sealed cavity. They are thin-walled structures that benefit not only from the geometrically nonlinear behavior, but also from the load sharing. Considering these effects, their behavior is studied using the nonlinear Finite Element Method and Particle Swarm Optimization. Different design criteria are imposed on the thickness determination of the glass panes with different shapes. Rectangular, triangular, and circular shapes are considered. The results show that the triangular shapes have the least weight for a given area when the deflection criterion is the dominating one. When maximum principal stress is the thickness defining criterion, the shapes perform almost equally well. The ratio between the pane thicknesses had the most influence on the behavior of the IGU. As it increases, i.e., one pane is significantly thicker than the other, the load sharing percentage drops, but it provides the most lightweight solution. Closer it is to 1, more equally the structural stresses are divided between the panes, i.e., redundancy is achieved. Finally, it is possible to establish a simple but effective method for the thickness determination of these IGUs using the results of this study. However, more work is required, including numerical analysis and experimental testing.     

Experimental study on dynamic response of a floating offshore wind turbine under various freak wave profiles

This study performed experimental investigation on the dynamic response of an in-place floating offshore wind turbine (FOWT) under freak wave actions. Based on the method of wave profile modulation, various freak wave profiles embedded in unidirectional Gaussian seas were generated in wave basin and the action of these waves on the FOWT was measured and analyzed, which has not been done before. The motions of FOWT were analyzed in time domain as well as time-frequency domain. The effect of freak wave parameters on FOWT motions was addressed, i.e., freak wave height, freak wave period, large crest, and deep trough. The dynamic response of FOWT was observed as a spike at the occurrence of freak wave in a conventional random wave, where the impact of freak wave can last for 17 spectral peak periods of wave. Data analysis shows that the motions of FOWT increased linearly with the freak wave height. In addition, the occurrence of freak wave induced the coupled effect on surge and pith, which was strengthen with the increase of freak wave height and wave period. Compared to a large crest, a deep trough of freak wave led to stronger motions and was supposed to be a key concern on the safety of the FOWT. The novel findings in this study provided a reference for the design of survival load on a FOWT and benchmarks for validating numerical models.     

A numerical study on the installation configuration design of compliant vertical access riser (CVAR) in deepwater

In oil and gas transportation, the compliant vertical access riser (CVAR) system conducts economic and operational advantages due to its special configuration. In this paper, the static performance of the CVAR is studied by an efficient numerical method. According to the unique configuration of the CVAR, the mathematical model is established based on minimum total potential energy principle. The equilibrium equations are discretized by finite difference method and then solved by Newton-Raphson technique. The accuracy of the numerical method is verified by OrcaFlex software. Detailed parametric analysis is carried out based on practical engineering requirements. The effects of buoyancy section's configuration including buoyancy factor, buoyancy section's length and buoyancy section's location, and external environmental factors including wellhead offset distance, water depth and current velocity on installation shape and mechanical properties of the CVAR are analyzed. The research shows that the presented numerical method has good applicability and flexibility for the early installation configuration design of marine risers which have no touchdown section but only one touchdown point and are equipped with multiple buoyancy blocks subjected to forces of different directions and magnitudes, such as CVARs.     

基于流变特性的消石灰改性油污泥热解残渣沥青胶浆稳定性研究

为探究油污泥热解残渣沥青胶浆性能,实现其在道路工程中的应用,开展了消石灰改性油污泥热解残渣沥青胶浆稳定性与改性机理研究。通过扫描电镜和红外光谱试验分析油污泥热解残渣的理化性质;在此基础上通过沥青胶浆三大指标和黏度试验,解析消石灰改性油污泥热解残渣沥青胶浆的掺配比;通过沥青弯曲蠕变劲度(BBR)和动态剪切流变(DSR)等试验评价了消石灰改性油污泥热解残渣沥青胶浆水稳定性能及高低温流变性能;最后通过微观试验解析消石灰改性油污泥热解残渣沥青胶浆的微观界面特性和改性机理。结果表明：油污泥热解残渣存在以中大孔为主、微小孔为辅的多孔体系,经消石灰改性后的油污泥热解残渣与沥青之间存在较强的物理吸附作用与化学吸附作用,提高了油污泥热解残渣与沥青之间的黏结力;消石灰掺量占填料总质量的30%时,其对油污泥热解残渣沥青胶浆的改性效果最佳;当粉胶比为1.0,消石灰掺量为30%时,与普通矿粉沥青胶浆相比,其水煮后的质量损失率减小了18.2%;-6℃、-12℃、-18℃时的蠕变劲度分别降低18.3%、16.5%、5.4%;64℃、70℃、76℃、82℃时的抗车辙因子分别降低6.9%、7.4%、3.3%、1.4%。...     

硬岩铁路隧道湿喷聚丙烯纤维混凝土支护结构稳定性分析

在隧道支护结构中采用湿喷工艺喷射聚丙烯纤维混凝土技术可以提高隧道围岩的稳定性,符合混凝土向高性能、绿色化、施工注重环境保护的发展趋势。在宝鸡-兰州复线东巨寺沟铁路隧道选取试验段中实施湿喷工艺喷射聚丙烯纤维混凝土,作为支护结构,并作永久性支护结构,免除二次衬砌工作。采用非线性有限元方法,分析了该铁路隧道试验段采用湿喷纤维混凝土支护结构的隧道围岩稳定性,分析了未支护和湿喷纤维混凝土支护的隧道围岩稳定性。分析结果表明：与未支护的隧道相比较,支护后的隧道围岩塑性区分布范围得到了减小,隧道变形微小。隧道变形实测结果表明：隧道的变形微小,处于稳定状态。     

基于模拟机实验的全自动驾驶人因可靠性分析

介绍地铁全自动驾驶系统中人因可靠性分析的应用,选取适于全自动驾驶(FAO)系统人因可靠性分析的方法,应用THERP+HCR方法分析人因失误概率.针对人误数据来源不足的问题,应用模拟机实验的方法,通过建立人误分析系统模拟运营场景中人员的行为,获取事故场景中人误数据.分析全自动驾驶人误分析系统的设计方案并详细描述各组成模块功能需求,结合典型的英国地铁事故实例,分析事故中的人误率.针对人的失误,提出改进措施,降低事故的人误率,提高控制中心人员的可靠性.     

模型准确性对系统管网泄漏诊断的影响分析

针对基于压力敏感性的管网泄漏诊断方法应用中由管网模型误差带来的鲁棒性问题,提出根据量化的模型准确度指标来分析诊断方法的有效性。利用FlowMaster流体仿真软件建立某实际冷却系统管网不同准确度下的水力模型。以该管网的标定模型为基准,采用改进的灰色关联度分析（IGR2）法对各模型与基准模型间各测点压力值的相似性进行评估来计算误差,得到模型准确度量化指标。采用故障诊断成功率（FDSP）计算泄漏诊断的有效性。基于不同准确度的管网模型进行泄漏诊断分析,获得不同准确度模型对泄漏诊断有效性的影响。结果表明,该泄漏诊断法的有效性随模型准确度的增大而提高,当管网模型准确度大于0.75时,故障诊断成功率均处于90%以上,说明该故障诊断方法对模型误差具有一定的鲁棒性。     

谈我省干线公路安全设施中存在的安全隐患与整治

结合工作实际,通过对目前我省干线公路安全设施中所存在的安全隐患进行了分析,并从安全设计理念、安全设施“三同时”、重点路段整治、安全作业、“三新”推广、安全意识、安全教育、安全培训、规章制度、责任追究、安全审计等多个方面阐述了看法和建议。