初速度对被撞船舷侧结构影响

采用ANSYS/LS-DYNA建立了两船发生侧向对中垂直碰撞的非线性有限元模型,模型中考虑了材料非线性、几何非线性等因素;并以所建立的非线性有限元模型为基础,对被撞船舷侧结构碰撞性能进行了仿真研究,得到了碰撞力和能量随碰撞船位移变化的关系曲线,重点研究了碰撞船初速度的影响.数值仿真结果表明,不同的碰撞船初速度会导致被撞船舷侧结构产生不同形式的变形和不同程度的损伤.同时,通过仿真计算得到了某一确定碰撞情景下被撞船舷侧内、外壳破裂的临界速度,可以为海事部门制定海上限速避碰规则提供依据.     

浮动核电站双层舷侧结构与球鼻艏碰撞计算分析

浮动核电站在运行过程中的安全性是其设计阶段需要着重考虑的问题,这其中就包括舷侧结构在发生船舶碰撞时的耐撞性能。参考20 000 t浮动核电站的结构形式,介绍了利用LS-DYNA对传统双层舷侧结构与刚性球鼻艏发生的微能碰撞所进行的有限元分析。参考舷侧结构简化模型的有关计算公式,提出了一种舷侧结构组合模型用于简化解析法的计算。通过计算得到了舷侧结构变形能随撞击深度变化的关系曲线,并将其与有限元分析所得结果进行了比较,得到了较好的拟合,验证了该方法的合理性及其实际应用价值。     

车架结构对微型客车碰撞能量分布的影响研究

本文以Lagrange法为算法为基础，采用动态显式非线性有限元分析技术，就车架结构对微型客车碰撞能量分布的影响特性进行了捞真研究。探讨了关键部件的建模处理及整车仿真参数设置与控制方法，妥善处理了仿真精度和计算效率的矛盾，实现了用较少的单元和镎短的时间对微小型客车正面碰撞的模拟。在此基础上，本文以添加第一横梁、第三横梁和保险杠前后的碰撞为例，对车架结构对微型客车碰撞能量分布的影响进行了仿真研究。模拟结果表明，第三横梁和保险杠对微型小客车的耐撞性起重要的作用，添加第三横梁和保险杠后，微型小客车正面碰撞时，碰撞能量分散较快，其纵梁前段和驾驶员座位下与前门槛板对应的纵梁部分基本未发生变形，整车的耐撞性得到了明显的改善 。     

八边形逐级吸能梁的设计与优化

研究了一种八边形截面逐级吸能梁结构的设计与优化方法.建立了八边形逐级吸能梁的有限元模型,通过台车试验验证了模型的有效性.采用均匀试验设计方法制订并进行了一系列不同壁厚的八边形逐级吸能梁碰撞仿真,利用仿真结果建立八边形逐级吸能梁的耐撞性回归方程,并进行了回归分析.利用遗传算法,以八边形逐级吸能梁壁厚为变量,对该吸能梁耐撞性进行多目标优化设计,获得一组耐撞性较好的八边形逐级吸能梁设计方案,并将优化方案用于车架耐撞性改进.仿真及试验结果表明,该八边形逐级吸能结构变形吸能均匀,能够更好地达到碰撞安全性要求.     

基于网格的汽车耐撞性数值分析系统及其应用

基于网格技术以及数值分析理论,分析了网格应用中间件以及具有4层结构的汽车耐撞性数值分析网格体系结构,结合耐撞性理论,提出了汽车耐撞性协同仿真和分布式耐撞性数据挖掘方法,实现了汽车耐撞性协同仿真应用系统与汽车耐撞性数据挖掘应用系统的融合.同时,结合应用实例,将所提出的方法及系统应用于汽车协同仿真及耐撞性数据挖掘活动中,取得了良好的效果.     

纯电动汽车正面抗撞结构耐撞性拓扑优化方法

为了解决纯电动汽车正面碰撞安全性差的问题,文章提出了一种综合考虑5种典型碰撞工况下整车优化区域以及动力电池布置分析的多目标耐撞性拓扑优化方法。基于混合元胞自动机(hybrid cellular automata,HCA)算法,耐撞性拓扑优化以单元相对密度为设计变量、结构内能密度分布统一为目标,运用固体各向同性微结构材料惩罚模型(solid isotropic material with penalization model,SIMP)下的变密度法进行材料分布;迭代收敛后,最终得到了传力路径优越、构型明朗清晰的耐撞性车身结构,同时得到符合整车性能要求的吸能纵梁形状。对优化后的整车模型进行的耐撞性验证表明,该优化结构让碰撞加速度与结构变形量同步最优化,大大增加了纯电动汽车正面碰撞的安全性,优化出的抗撞结构为纯电动汽车正面耐撞性设计提供了一定的参考。     

桥墩复合材料防车撞结构碰撞性能试验研究

针对桥墩车辆碰撞的问题,设计了钢夹层和蜂窝复合材料相结合的桥梁防车撞吸能结构.为研究耐撞性能进行了材料性能试验和全尺寸防撞结构的碰撞试验,试验得到最大碰撞力为547.6 kN.通过对比试验获得碰撞响应与规范设计值,得出试验结果满足碰撞条件容差要求,可用于后期的数值模型验证,为类似吸能结构的设计提供参考.钢夹层-复合材料桥梁防车撞吸能结构可以减小桥墩的局部损伤和整体破坏,从而达到保护桥墩的目的.     

基于临界碰撞速度的船舶结构耐撞性优化

分析船舶结构碰撞破损、能量转换和碰撞力间的关系,提出以临界撞速为耐撞性指标的船舶结构耐撞性评价模型,建立了船舶结构耐撞性优化方程.以2艘渔船发生正碰为例,开展了船舶碰撞的数值计算.比较了撞击速度对结构碰撞特性的影响,确定了临界撞击速度,给出了以提高船舶结构临界撞速为目标的结构改进建议.数值计算结果表明,基于临界撞速的船舶结构耐撞性评价指标具有可行性.     

钢铝混合汽车前纵梁的耐撞性优化方法比较

为了解决汽车前纵梁碰撞时峰值碰撞力和吸能量之间的矛盾,通过对前纵梁前端使用铝合金、后端使用高强度钢板,提出了一种钢铝混合前纵梁结构.以纵梁两端所用材料类型及厚度为组合变量,建立了该结构轻量化和耐撞性多目标优化问题的数学模型,并对多项式、Kriging和径向基函数(RBF)3种常用近似模型解决该特定问题的适用性进行了研究.结果表明,RBF更适合作为近似模型解决材料类型和板厚的组合优化问题,且优化后的前纵梁结构能在改善耐撞性的同时,显著提高轻量化水平.     

基于混合模型汽车结构耐撞性的可靠性优化设计

针对多种不确定性因素对汽车结构耐撞性产生的影响,本研究提出了一种基于混合模型汽车结构耐撞性的可靠性优化设计方法.首先,建立了基于概率-区间混合模型汽车结构耐撞性的可靠性优化设计模型,并分析其嵌套情况;然后,为了减少嵌套层数,提出了一种高效的解耦策略,将原始的嵌套问题等效转化为单层的优化设计问题;最后,使用径向基函数构建...     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with