CSR对超大型油船结构设计的影响

国际、国内的油运市场对超大型油船(VLCC)的需求非常迫切.油船结构共同规范(CSR)对VLCC结构设计的影响是全面和系统的.文章以30.8万吨VLCC为例,对使用CSR进行了较为深入的研究,包括总纵强度、中剖面设计等关键技术问题,在此基础上初步阐明CSR对VLCC结构设计的影响.     

平台支撑的潜艇内部平面舱壁极限强度的模型试验研究

为了研究平台支撑的潜艇内部平面舱壁极限强度,根据实艇舱壁结构,按1∶2的缩尺比设计制作了一个舱壁模型,采用内压试验方法进行了模型极限承载能力的试验.利用国际通用的大型非线性有限元分析软件MSC/MARC,对舱壁模型进行了几何/材料的双重非线性的有限元分析,试验值与有限元分析计算值吻合良好.通过对模型试验结果的分析,得出了一些对指导潜艇平面舱壁结构设计有实用价值的结论.     

城市轨道交通中单趾弹条扣件的弹条强度分析

文中采用有限单元法建立了单趾弹条的实体模型,针对设计工作状态,计算其服役期间的等效应力分布和扣压力水平,并对其中肢约束长度、弹程和弹簧钢半径的特性影响进行了分析。通过分析发现,弹条的最大应力出现在中肢和趾端过渡小圆弧处,值得其生产、安装、运营养护时关注;而在相关的特性影响分析中,弹程影响较大,中肢约束长度和弹簧钢半径的影响较小。     

重庆朝天门长江大桥高强度螺栓群栓试验研究

针对重庆朝天门长江大桥拼装式节点板层多、板束厚度大、外形尺寸变化大及单个节点高强度螺栓数量多等特点,结合重庆地区气侯条件、该桥设计采用的抗滑移摩擦面技术参数和目前国内高强度螺栓连接副的性能,选取具有代表性的不同板厚组成的板束,通过压力传感器及静态应变系统进行了群栓模拟试验。通过群栓试验,了解了高强度螺栓预拉力随时间变化的损失情况,螺栓施拧先后顺序对栓群预拉力的影响,用终拧扭矩值的50%作为厚板的初拧扭矩时板束密贴情况,确定了高强度螺栓终拧扭矩检查时机,验证了该工程高强度螺栓施拧工艺的可操作性。该试验研究为今后类似工程的施工提供了宝贵的数据和经验。     

计及温度应力的沥青船强度有限元计算

本文应用MSC/PATRAN软件建立了一艘5000吨级沥青船舱段有限元模型,计算了温度场以及计及温度后的合成应力。结论得出了温度应力对沥青船结构设计带来的影响。     

汽车排气系统动态响应特性及强度分析

摘要：汽车排气系统的振动是影响汽车振动噪声和舒适度的主要因素之一,掌握其动态特性对优化汽车的NVH性能十分重要。在某客车新型排气系统的开发过程中,采用有限元分析方法,对排气系统进行模态、频率响应和强度分析,考察排气系统的整体性能,为排气系统的结构设计提供依据。     

等效波的散货船舱口角疲劳评估应力组合方法(英文)

The stress combination method for the fatigue assessment of the hatch corner of a bulk carrier was investigated based on equivalent waves.The principles of the equivalent waves of ship structures were given,including the determination of the dominant load parameter,heading,frequency,and amplitude of the equivalent regular waves.The dominant load parameters of the hatch corner of a bulk carrier were identified by the structural stress response analysis,and then a series of equivalent regular waves were defined based on these parameters.A combination method of the structural stress ranges under the different equivalent waves was developed for the fatigue analysis.The combination factors were obtained by least square regression analysis with the stress ranges derived from spectral fatigue analysis as the target value.The proposed method was applied to the hatch corner of another bulk carrier as an example.This shows that the results from the equivalent wave approach agree well with those from the spectral fatigue analysis.The workload is reduced substantially.This method can be referenced in the fatigue assessment of the hatch corner of a bulk carrier.     

45m混凝土泵车结构强度研究

以45 m混凝土泵车为研究对象,利用ANSYS有限元软件,采用实体单元与接触单元相结合的方法模拟各个臂架之间的连接,用板壳单元和梁单元模拟泵车其余结构,建立了整车有限元模型.分析泵车在3种典型工况下的结构强度,发现混凝土泵车臂架在危险工况局部结构强度不能满足设计要求,通过计算分析提出了结构补强方案.改进后的结构实际使用情况良好.     

Degradation of bond strength and deformation between TRC-confined seawater sand concrete and BFRP bars under chloride corrosion environment

The interfacial bonding performance between seawater sand concrete and basalt fiber reinforced polymer (BFRP) bars were tested under different textile reinforced concrete (TRC) confinement layers, confinement sequences and chloride salt dry-wet cycles. The results show that TRC confinement can change the failure mode of the specimen and improve the ductility of specimens. With the increase of corrosion age, compared with the specimens with the same restrained layers in the conventional environment, the ultimate bond strength of restrained specimens before corrosion gradually decreases, and the slip value when reaching the ultimate bond strength also slightly decreases. The bond strength of the pre-restrained corroded specimens has the same development trend. Based on the bond-slip model of deformed steel bars and concrete proposed by Eligehansen for the first time in 1983—BPE model, under the control of TRC confinement and corrosion age, the relationship between the TRC confinement layer and the ultimate bond strength and slip of seawater sand concrete and BFRP steel bar is established. By fitting and predicting the ultimate bond strength, corresponding slip value, and corrosion age control of different TRC confinement layers, it is found that the confinement effect will not be significantly improved when the confinement layers exceed 4 layers. Under long-term chloride corrosion, the failure mode of the specimen may still change into splitting failure when the number of restrained layers is small.     

Numerical investigation on the ultimate strength behaviour and assessment of continuous hull plate under combined biaxial cyclic loads and lateral pressure

The ultimate strength of continuous hull plate under combined biaxial cyclic loads and lateral pressure is investigated in the present paper by using nonlinear finite element method. Geometric nonlinearity due to large deflection and material nonlinearity induced by kinematic hardening and isotropic hardening are both accounted for. A parametric study is designed and completed to examine the longitudinal ultimate compressive strength behaviours in the cycles on the basis of a large number of load-shortening curves. Effects of series of parameters especially the plate slenderness ratio, transverse cyclic compression, lateral pressure and cycle number are analyzed with details. It is found that the strength characteristic and collapse mode are highly affected by the coupling influence of the mentioned factors as well material behaviours. A dimensionless unified formulation as a function of the decisive factors is empirically proposed to accurately assess the ultimate strength of continuous hull plate in various cycles.