A Matlab Based Numerical Simulation Analysis of Shore Stress in Vacuum Plate Glass

A numerical simulation method, the node method, and single, multi-triangle progression were used to analyze the shore stress field of vacuum plate glass. By optimizing the shore distribution, the points of greatest and least stress in vacuum plate glass were determined. The distributions of greatest stress in vacuum plate glass were calculated using MATLAB. These calculations can provide numerical foundations for accurately analyzing the shore stress and flexibility of vacuum plate glass. The result shows that the greatest stress exists in the end surface of every shore, and the maximal stress is in the second shore at four-square sides, then follows the shore of next row. The theoretical calculations correspond to the software analysis results.     

Brake disc thermal stress in material composite design

The temperature distribution and thermal stress distribution of brake discs under emergency braking conditions were studied using the finite element method (FEM). The discs were of three types: those made of functionally graded SiCp/Zl104 composite materials, of uniform (20% volume) SiCp/Zl104 composite materials, and of compacted graphite iron, respectively. The rule of mixtures of dual phase material and the discretization of the material composition distribution were applied to estimate the material properties of functionally graded composite materials. The results show that the temperature and thermal stress of brake discs made of graded SiCp/Zl104 composite are the lowest among the three types studied, and the distribution of temperature and thermal stress of this brake disc type is more uniform than the others. Furthermore, brake discs made of functionally graded SiCp/Zl104 composite can reduce vehicle weight and increase wear resistance capacity. The results provide a theoretical foundation for fabricating brake discs made of graded SiCp/Al composite material.     

system modeling and simulation of wind turbines

Wind turbines operate in harsh environment with transient and variable working conditions. As a result, wind turbines are complicated, nonlinear, uncertain systems. Modeling and analysis of these systems are crucial to their design. Based on MATLAB, a new dynamic simulation model of a stalled wind turbine was presented. The blade element momentum theory and the state space method were programmed into MATLAB/SIMULINK to calculate wind turbine aerodynamic performance. The generator was also modeled in MATLAB/SIMULINK, taking the coupling between the generator and the rotor speed into consideration. Based on the proposed MATLAB model, an analysis of a 600 kW wind turbine was carried out. The calculation values were compared with the measured data. The results indicate the correctness of the proposed MATLAB model. The simulation model can be applied to optimize design and control of stalled wind turbines.     

contact stress and steady thermal analysis of herringbone gears in a gas turbine

To obtain the distribution characteristic of contact stress and the bulk temperature on the surface of herringbone gears, parameter modeling of gears was carried out by parametric design language. A numerical simulation was given to calculate the contact stress field and the steady thermal field by combining heat transfer theory, tribology theory, and mesh theory. The distribution of contact stress, the bulk temperature and heat flux also were analyzed. The analysis results show that the distribution of the load along the contact line possesses regularity. The heat flux along the tooth depth direction decreases first and then increases. The effect of thermal conduction of the tooth is stronger than that of convective heat transfer. The conclusion indicates that the finite element emulation method can be used to estimate the transmission performance of herringbone gears.     

烤烟典型缺钾症表现的农艺性状及相关营养元素分析

针对近年来在玉溪市大田烤烟生产上发生的严重的烤烟典型缺钾症,以根际土壤及植株各部位器官等为探索对象,采用对比分析法探讨了红花大金元和K326烤烟典型缺钾症表现的农艺性状及相关营养元素含量状况。结果表明,烟株发生严重缺钾症后,外部不但表现典型症状,还表现叶片的长、宽及茎直径有所下降．从而导致单株的地上部和地下部的干物质积累量显著下降,同时烟株内部的营养元素含量及其相互协调性与正常株相比也发生了显著的变化。典型缺钾症烟株的根部及各个叶位的叶片和茎杆．不但K含量显著降低,而且各个叶位的叶片和茎杆的Mg、Zn（中上部茎）、B含量也明显下降;各个叶位的叶片N、Ca、Mn、Fe含量则显著提高,K326烟株各个叶位茎杆及红花大金元根部的含N量也明显提高,但K326烟株根部及红花大金元茎部（中上部）的含N量又明显下降;典型缺钾症烟株的根部、茎部及各个叶位的叶片N／K、Ca／K和Mg／K含量则显著提高。红花大金元（地烟）典型缺钾株的根际土有效养分含量除N地。N有所升高外,不但有效K含量呈显著降低,而且有效态N、P、ca、Mg、Zn、Mn、B、NO3^-N也降低;K326（田烟）典型缺钾株的根际土有效K含量也表现显著降低,但NH4^-N和NO3^-N表现出显著的升高。而有效态Ca、Mg、P、Zn、B、Mn的含量变化不明显。     

客车车身振动仿真分析

首先建立了汽车车身结构的有限元模型,并进行了有限元计算模态分析;通过比较计算模态和试验模态,验证了车身结构有限元模型的正确性;基于模态分析的结果,提出了车身减振的改进方案,并且对改进前后的车身结构进行动态特性仿真分析,仿真分析结果表明,该改进方案能有效减轻车身结构的振动,可以作为控制车身振动,进而控制车内低频噪声的一条途径。     

红皮树穴盘育苗技术研究

[目的]提高红皮树容器育苗的出苗率、成苗率和移栽成活率,为其开发利用提供优质苗木。[方法]设计3种基质配方3、种穴盘规格、不同配比的肥料在2种光照强度下进行红皮树穴盘育苗试验,探索红皮树穴盘育苗技术。[结果]泥炭+珍珠岩、森林腐殖土+黄心土、树皮粉+黄心土3种基质配方均较适合红皮树穴盘育苗。苗木生长与穴盘容积呈正比。不同生长期肥料配比与苗木质量关系密切。加盖60%透光度遮阳网处理的苗木生长正常,质量指数比全光照处理高27.3%。[结论]培育半年红皮树苗可选用72S型育苗,1年苗可选用林50T型育苗,困难地造林可选用林72T型育苗。苗木速生期和生长后期宜按一定配比施用N∶P∶K液肥。     

绥化市北林区气候变化与对策

根据北林区1953～2006年历年地面气象观测数据,采用一元回归方法,定量分析了绥化市北林区的气候变化,结果表明,研究期内该区气温升高,和热量相关的其他要素均有较明显的与增暖相对应的变化;降水年总量变化不大但各月略有不同变化,暴雨日数明显增加;日照时数有所减少;空气相对湿度稍有降低。并针对这些变化,提出了相应的应对措施。     

广东省观光农业园景观影响因素研究

让观光农业园以更加丰富多彩的形式体现其功能,是目前广东省观光农业园规划建设急需解决的问题。该文从广东省观光农业园景观的影响因素入手,分析景观意象、景观构成、景观特征、声音要素、行为特征等几方面在园区设计中的应用与特点;并结合广东省观光农业园的实际,探讨规划设计中如何利用这些影响因素,营造出有区域特色的观光农业园景观。     

圆不锈钢管混凝土轴压力学性能的有限元分析

在确定了不锈钢与核心混凝土的材料本构模型、单元类型以及界面接触模型的基础上,根据构件的几何和材料非线性,建立了圆不锈钢管混凝土轴压构件的有限元模型.算例分析结果表明,有限元计算和试验结果总体上吻合良好.利用有限元模型,比较了不锈钢管混凝土和普通钢管混凝土轴压构件的荷载-变形关系曲线.