船用钢板漏磁检测的三维有限元分析     

李寒林  林金表  蔡振雄  林俊明  何宜东 《厦门水产学院学报》2010,(6):458-460

为保证船舶的安全,满足对船用钢板进行定期检测的需要,提出利用漏磁检测钢板缺陷的方法,并对该方法进行了三维有限元分析和实验验证.在ANSYS软件中建立检测传感系统、磁化装置和钢板缺陷的三维模型,进行钢板缺陷附近的磁场分布状态的数值仿真,得出了船用钢板磁化后的磁场分布状态,计算出缺陷与磁场分布之间的对应关系曲线,并对缺陷进行判断.检测实验结果证明有限元计算是可靠的.  相似文献   

调减木材产量对伊春市林产工业及相关产业的影响及相关对策     

吴士兵 《林业科技情报》2008,40(4):14-16

通过对伊春林区的深入调查研究，分析了调减木材产量后对林产工业及相关产业的影响，并提出了相应的对策。  相似文献   

一种油罐底板实时监漏的新方法     

杨金林  刘丽川  何旺  方伟  陈涛 《油气储运》2013,32(7)

针对当前被广泛使用的通过罐内油位变化和感官查库对油罐底板进行实时监漏的方法存在的弊端,提出了油罐底板实时监漏的新方法,即油罐基础内钻孔油气体积分数监漏法.介绍了油罐底板实时监漏方法的探漏原理:在油罐基础上按每9m(弧长)钻取一个直达砂垫层的探漏孔,使用高灵敏度的油气含量检测仪探测到油气,可判断罐底是否发生渗漏.以实例阐述了操作步骤和现场应用情况,证明了其有效性,详述了其技术要求.基于现场实验数据,提出了汽油油罐的判漏标准,可为今后油库的扩容和改造提供借鉴.  相似文献   

压力容器制造中存在的问题及解决方案   总被引：1，自引：0，他引：1  

孟庆久  刘康勇  石中玉 《油气储运》2002,21(4):50-52

通过对压力容器在制造过程中出现的问题进行理论分析和计算，提出了如何控制钢板的最小弯曲半径、消除钢板端部剩余直边、调整三辊卷板机参数等具体方法。  相似文献   

FEM Dynamical Analysis of the Reinforced Concrete Beam with Bonding Steel Plate     

LIU Min  YIN Xue-gang 《保鲜与加工》2005,(1):140-142146

In order to researchmechanical capability of the reinforced concrete beam with bonding steel plate, adopting separatemethod to establish finite element model of the reinforced concrete beam with bonding steel plate, using FEM to study dynamical characteristics of the model, have got good results which can not be easily got using traditional resolution method, which can give referenceto study dynamical characteristics of the reinforced concrete beam with bonding steel plate.  相似文献   

微热管阵列平板太阳能集热器中空保温层厚度优化     

邓月超  赵耀华  全贞花  刘中良 《农业工程学报》2015,31(5):268-274

为分析微热管阵列平板太阳能集热器的热性能,该文建立了集热器的CFD模型,对其进行数值模拟,将模拟结果与试验结果进行对比,验证了模型的可靠性。采用该CFD模型对集热器保温层厚度进行优化,结果表明,当实心保温层导热系数分别为0.02、0.03、0.04、0.05W/(m·K)时,优化的实心保温层厚度分别为4.5、5.0、5.5、5.5cm。合理设计的中空保温层(空气层与实心保温层相结合的保温层形式)集热器能够达到与实心保温层集热器相当的保温隔热效果,同时可使集热器保温层成本及质量降低25%~50%。最后,该文给出了保温层总厚度分别为4、5、6cm时的中空保温层厚度优化结果,为该类集热器保温层的设计提供了理论依据。  相似文献   

板齿摘脱滚筒的核心功能——吸附作用的理论研究   总被引：10，自引：2，他引：10       下载免费PDF全文

蒋亦元 《农业工程学报》1997,13(1):57-62

从观察现象出发，经理论分析旋转气流所产生的使茎秆、穗头向滚筒贴附的作用，揭示了该作用与板齿结构和运动参数间的关系，并对环流流场的流速、压头的形成亦进行了分析。实验测定结果，基本验证了这些关系  相似文献   

提高土壤抗蚀性措施研究   总被引：3，自引：0，他引：3  

孙传生  王艳玲 《中国水土保持》1994,(2):17-18

土壤抗蚀性是影响土壤侵蚀最基本的因素之一。提高土壤抗蚀性的措施主要有：提高土壤胶体的含量和质量　；改良土壤结构；采用少耕法　和免耕法耕作；采用秸秆、砂石、作物残茬、　地膜、青草等覆盖耕作法；　提高土壤有机质含量　；种植根系发达的植物。  相似文献   

Effect of subcritical hydrophobicity in a sandy soil on water infiltration and mobile water content     

Axel Lamparter  Markus Deurer  Jrg Bachmann  Wilhelmus H. M. Duijnisveld 《植物养料与土壤学杂志》2006,169(1):38-46

Recent research shows that most soils are more or less water repellent. Already subcritical water repellency may cause incomplete soil wetting and preferential flow. Both processes potentially reduce the residence time of water and solutes in the vadose zone, resulting in an enhanced risk of groundwater contamination. The objective of the present paper is, therefore, to evaluate the impact of reduced soil wettability on the soil water infiltration rate and to investigate the tendency towards preferential flow with the analysis of the immobile water content in the infiltration zone. In november 2002, a field experiment was done in a coniferous forest, 30 km N of Hannover, Germany. Soil hydrophobicity was quantified by measuring the contact angles. The hydraulic conductivity of the podsolic sandy soil was measured depth‐dependent with a double‐ring tension infiltrometer in three soil horizons. To quantify possible preferential‐flow effects, a LiBr‐Tracer was added to the infiltrating water to evaluate the mobile water‐content fraction after infiltration. Additionally, infiltration rates of water were compared with infiltration rates of ethanol which were determined after water infiltration at the same locations. Results show that the actual water repellency of field‐moist soil was mainly subcritical (contact angle <90°). Water infiltration rates were reduced due to subcritical repellency by a factor of 3–170 compared with ethanol infiltration rates (exclusion of wetting effects). This spatially variable infiltration behavior was not clearly reflected neither by the small‐scale contact‐angle measurements nor by the analysis of the average immobile soil water content in the infiltration zone. We conclude that this specific infiltration behavior of water caused by small‐scale wettability effects may temporarily reduce the local connectivity of water‐flow pathways.  相似文献   

Mechanical Model of Steel Plate Composite Shear Walls     

GUO Zhen  YUAN Ying-shu 《保鲜与加工》2011,(5):51-56

Based on concepts of mechanics, a mechanical model of novel type of steel plate composite shear wall is presented. The novel type of structure is formed by steel plate shear wall and T-shaped solid-web composite columns. Flexural stiffness of steel beams, lateral stiffness of the T-shaped solid-web composite columns, shear stiffness of steel plate composite shear wall and shear stiffness of beam-column connection are taken into account in the mechanical model. And the equivalent damping between steel plate and boundary is considered. Based on the deformation features of structures and the calculation hypothesis, the lateral stiffness model and the energy dissipation model of structures are developed. Meanwhile, the calculation equations of elastic ultimate and plastic ultimate of shear strength of structures are set up. The theoretical analysis results inosculate better with the results of experiment. The comparison between the result calculated from the formula and the experimental result shows that the calculation precision is high enough to meet the demand of theoretical analysis. The difference, including equivalent model, stress states, manufacturing defect and installation error, between the formula and the experiment has been further discussed.  相似文献