共查询到19条相似文献,搜索用时 234 毫秒
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分析甲醇柴油的十六烷值、密度、运动粘度、腐蚀性和馏程等性质。采用数值计算的方法研究不同甲醇掺混比例对混合燃料十六烷值的影响;开展燃料的蒸馏特性试验、粘温特性试验,研究不同甲醇掺混比例(M0、M10、M20)对混合燃料的蒸馏特性、粘温特性的影响,初步探讨柴油中甲醇含量的混合燃料理化参数的影响规律。 相似文献
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在异步电动机三相原始动态数学模型的基础上,应用SIMULINK建立了仿真模型,对异步电机直接起动、串电阻起动和降压起动进行了仿真分析,证实了降压起动的优势。同时运用MatLab软件M语言进行了数值计算,分析了三相异步电动机的机械特性,其结果直观准确符合实际。 相似文献
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介绍了Taylor-Couette流场的研究内容和研究意义,分析了计算流体力学(CFD)和Taylor-Couette流场数值模拟的发展状况和研究进展等,总结了常用于Taylor-Couette流场数值模拟研究的3个方法及其特点,探讨了当前Taylor-Couette流场的数值模拟研究存在的问题,提出了相应的解决方法。 相似文献
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实木家具T形构件抗拔力的数值仿真 总被引:1,自引:0,他引:1
利用Abaqus有限元分析软件平台,以家具中典型的直角榫接合T形构件为例,建立了一套针对榫接合实木家具抗拔力分析的有限元数值计算模型。对T形构件进行了抗拔力的数值模拟,并用库伦摩擦定律进行了理论分析。结果表明模型的计算结果与理论分析结果具有一致性,从而证明此数值计算模型可以用于模拟实木家具节点力学行为,并为进一步研究整体家具结构力学的数值分析打下基础,为名贵家具结构力学性质的无损检测以及结构设计提供方法。 相似文献
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用响应面有限元法分析既有混凝土桥梁的可靠性 总被引:1,自引:0,他引:1
基于响应面有限元的可靠度计算是采用有限元数值模拟来解决功能函数不能明确表示的结构可靠度计算问题的一类方法,对于大型复杂结构的可靠度分析有重要的意义.基于ANSYS的响应面法分析了一座既有桥梁的可靠性.数值模拟与试验结果对比表明,该方法可以很好地评价既有混凝土桥梁的可靠性,为结构可靠度分析计算提供了新的有效途径. 相似文献
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根据经典承载力理论,增大基础埋深可提高地基承载力,但基础自重也会随之增加,而采用裙板式基础可解决这一矛盾。目前对裙板基础承载力研究多集中于圆形基础,对其他形状的裙板基础承载力研究较少。以黏性土中裙板式条形基础为研究对象,采用数值模拟方法,研究了裙板式基础破坏时的地基变形特性,然后采用理论推导的方法计算不排水极限承载力。数值计算结果表明,裙板式基础的变形破坏模式与相同埋深的实体基础类似,裙板的设置使极限承载力明显提高。裙板的相对高度d/b越大,地基承载力越高。根据裙板基础的破坏特征,可采用梅耶霍夫承载力理论分析地基极限承载力。通过推导,得到了在内摩擦角为零时、裙板式条形基础的不排水极限承载力计算公式。为了验证公式的有效性,将公式解答和数值计算结果与国外学者得到的经验公式的解答进行了对比。结果表明,推导出的公式同数值计算解比较接近,能简便计算出裙板式条形基础的不排水极限承载力。 相似文献
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王沛林 《中南林业科技大学学报(自然科学版)》1988,(1)
本文根据流量模数的倒数曲线法,利用合轴图及数值叠加规则,提出了一种适用于山区河道的图解计算方法,本法解算过程较为直观,便于检查正误,计算精度较高,特别是在需要绘制一系列流量水面曲线的情况下,可加快计算的进度。 相似文献
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介绍了鸭嘴式移栽机的工作原理,分析了该机移栽机构的工作过程,建立了鸭嘴式移栽器的运动学数学模型。在给定初始条件下,利用MATLAB软件对移栽器的运动进行了数值计算,并绘制出其工作曲线。分析移栽器的运动轨迹特征,可为合理确定移栽机构的结构和动力输入参数提供依据。 相似文献
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为了解决无卡轴旋切机圆木旋切过程中进给电机转速与刀刃所处水平位置的数学模型计算耗时的问题,本文采用Mathematica工具对转速函数进行多项式拟合,得出简单且便于单片机运算的拟合函数.同时运用Mathematica比较分析了原函数和各次拟合函数间的转速差及加工后的单板厚度误差. 相似文献
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本文采用柱坐标,以椭圆—阿基米德螺线包络组成解析曲线椭圆柱体的弯曲原木的数学模型。定义它为C型弯曲。并以材长和弯曲弓背长度定义,提出了一个实测参数的弯曲原木材积计算公式。定量地解决了弯曲造成原木材积统计时的损失。这种方法和理论,可以解决弯曲原木最佳出材率和弯曲原条最佳截断问题。为制材的数控软件编制提供了理论基础。 相似文献
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指出了城市初期雨水污染评价是水环境治理的关键问题之一。但因为存在错峰稀释等影响因素,目前除经验参数法外,少有能较精确定量计算城市单场降雨初期雨水污染的方式。基于此,提出了一种用范围值表示城市单场降雨初期雨水污染的定量计算方法,并基于SWMM模型予以了实现。算例结果表明:采用该方法可以较科学地定量评价城市单场降雨初期雨水污染水量。 相似文献
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基于有限元法的ANSYS软件对简单的升压型BOOST开关变换电路进行了场路耦合建模并对其进行分析,将仿真结果与MATLAB/simulink环境下的仿真结果做了对比,通过实际演算验证了场路耦合电路模型是正确的。结合作者以前文章表明ANSYS软件适用于电子器件及电路进行电磁场分析,为在电磁场分析方面做研究的工作人员及科研工作者提供了一种有效的参考方案。 相似文献
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Katsushige Shiraki Yoshiki Shinomiya Hirofumi Shibano 《Journal of Forest Research》2006,11(6):439-447
Numerical experiments of soil water movement and bedrock infiltration based on a simplified simulation method were conducted
to analyze watershed-scale rainfall-runoff processes. To verify the model accuracy, it was applied to a Minamitani watershed
(0.45 ha). The simulation was performed with 2.5-m space grids horizontally and five cells vertically. Results of long-term
calculation of this model proved that this simulation model is robust and demonstrated good computational water mass conservation.
Calculation results showed the best agreement with observed hydrographs and the number of groundwater levels simultaneously
when laboratory-tested soil hydraulic characteristics for topsoil were used and infiltration into bedrock was included in
numerical calculations. Numerical experiments show that bedrock infiltration generated a stable base flow and suppressed the
secondary discharge peak. The reproducibility achieved by observed soil hydraulic characteristics with the assumption of bedrock
flow demonstrates the effectiveness of the simulation model used in this article for analyses of watershed-scale soil water
movements. 相似文献
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ANSYS在杨木-秸秆层合梁弯曲分析中的应用 总被引:1,自引:1,他引:1
利用ANSYS有限元程序包对杨木-秸秆复合材料层合梁的弯曲问题进行分析,并与各种理论和实验结果进行比较.结果表明,利用ANSYS进行杨木-秸秆复合材料应力和变形方面的数值计算研究具有较高的精度和准确性. 相似文献
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A continuum failure criterion applicable to wood 总被引:1,自引:0,他引:1
Tom A.C.M. van der Put 《Journal of Wood Science》2009,55(5):315-322
The failure criterion is an essential part of all strength calculations of design. It was shown in the past that the tensor-polynomial
equation could be regarded as a polynomial expansion of the real failure surface. Now it is shown that the third-degree polynomial
is identical to the real failure criterion. It is also shown that the second-degree part of the polynomial is identical to
the orthotropic extension of the von Mises criterion for initial yield. The third-degree polynomial hardening terms of the
criterion are also shown to incorporate the earlier theoretical explained mixed-mode I-II fracture equation, showing hardening
to be based on hindered microcrack extension. For uniaxial loading, the failure criterion can be resolved in factors, leading
to the derivation of extended Hankinson equations. This allows the relations between the constants of the total failure criterion
to be elucidated, which is necessary for data fitting of this criterion and providing a simple method to determine the constants
by the simple uniaxial, oblique-grain compression and tension tests. Based on this, the numerical failure criterion is given
with the simple lower bound criterion for practice and for the codes. 相似文献
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Renke Coordes 《European Journal of Forest Research》2013,132(2):297-311
When forest stands are established by planting, the initial density is often chosen based on recommendations of specific plant numbers. Since forest owners typically face different alternatives for the employment of their opportunities and since market situations often change more rapidly and on a smaller scale than the characteristics of forest sites, the question arises whether these factors are reflected in one or within a small range of planting densities. Even though some advised densities might be profitable for some forest owners and market situations, the shift of profitable timber production as a result of changes in the circumstances surrounding the investment is unclear. In this paper, the influence of the planting density on the profitable production of timber is analysed with the explicit inclusion of price differentials as these offer incentives for the choice of the planting density in Central Europe. Since numerical calculations based on empirical data are required for an analysis of the complex facets of price differentials, the specific statements are restricted to the tree species Norway spruce (Picea abies Karst.). By means of typical calculation examples, the effects of changes in investment parameters are exemplified and discussed against the background of a sensitivity analysis. The results reveal the boundaries for the profitable production of high-quality timber and show that forest owners might compensate changes in the investment situation by adjustments of either or both the rotation age and the planting density. 相似文献