直接数值法
- 与 直接数值法 相关的网络例句 [注:此内容来源于网络,仅供参考]
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Meanwhile, confirm the weight coefficient through domain decomposition method, analytic hierarchy process, sequence for importance and fuzzy-subset inference method, so as to set up weight coefficient computing model.
并采用直接给出法、层次分析法、重要性排序法和模糊子集法确定权重系数值,建立权重系数计算模型。
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The discrete element method and the finite element method have their own advantages and weaknesses. Basically, the DEM was developed for predicting the failure problems accompanying with the transition from continuum to non-continuum media. However, it is not accurate to calculate the problem of continuum media. The FEM may forecast the failure area of the material reasonably, while it is hard to calculate the failure process in brittle media. Therefore it becomes a good choice to combine the two methods to construct a hybrid model.
离散元法和有限元法等数值计算方法各有其优势,同时也都存在不足之处:离散元法适于处理由连续介质向非连续介质转化的破坏问题,但对于连续体计算结果精度不高;有限元法适于预测材料破坏的区域,但难以直接用于计算脆性材料破坏过程,因此将两种方法结合可以形成一种较好的混合模型。
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Fourth precision solution can be derived from two grid sets solution with a second precision central difference scheme by Richardson extrapolation. It reduces the amount of calculation. Uncertainty is determined from the discretization error analysis. A finer grid calculation is made to validate the extrapolation scheme.
对于2阶精度中心差分格式的2套网格数值解,用Richardson外推法可以得到4阶精度的解,其工作量比直接求解4阶离散方程的工作量减少许多;对于计算中的数值不确定度,用该方法分析了离散误差,并用逐次加密网格的方法探讨了外推法的合理性。
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Direct method of Gaussian elimination, Gaussian main-element elimination, and the iterative method of Jacobi iteration, Gauss - Seidel (Gauss - Seidel) iterative method is linear equations numerical solution of important ways.
直接法中的高斯消去法、高斯列主元消去法,以及迭代法中的雅可比迭代法、高斯-赛德尔(Gauss-Seidel)迭代法又是线性方程组数值求解的重要方法。
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In order to reasonably depict four basic problems with friction, one Coulomb friction new form in first Kirchhoff stress is proposed to deal with finite deformation problems, other Coulomb friction form in incremental mode to elastoplastic flow theory; Hilbert function spaces concerning elastoplastical problems with friction are established, so it makes all operations and calculations in the treatise standardized within the scope of reasonably topologic structure; In view of functional extremum, the equivalence between generalized variational inequalities principles in elastoplasticity with friction and corresponding basic problems are testified by inducing Lagrangian multipliers, so it provides a rationally theoretical basis for numerical methods in elastoplasticity with friction; From the viewpoint of variational inequality, the theory of generalized variational inequalities in elasticity and elastoplasticity with frictional constraint is studied, and the uniqueness and existence of the solution of FEM is proofed under the proposed conditions of stress compatibility, and them FEM approximation and a discrete solution are discussed; Based on the principles of generalized variational inequalities in elastoplasticity with friction, direct generalized variational inequalities methods is pretended, which is a natural generalization and development of direct variational methods; Using generalized variational inequalities methods, some examples in metal forming including plane deformation, upset and extrusion are analyzed and the results prove that all the theories and methods in the paper are right, feasible, accurate and advanced.
主要内容有:为了合理地描述金属塑性成形中摩擦约束弹性、弹塑性基本问题,提出和研究了有限变形下以Kirchhoff第一应力表示的Coulomb摩擦定律形式和弹塑性流动理论下以增量形式表示的Coulomb摩擦定律表示形式;系统建立了摩擦约束弹塑性问题的Hilbert函数空间,使本文规范在一个具有合理的代数拓扑结构内进行一切操作和运算;利用Lagrange乘子,从泛函极值的角度系统地阐述和论证了一系列摩擦约束弹性、弹塑性广义变分不等原理与相应的实际问题之间的等价性,它为处理摩擦约束的弹塑性力学数值方法提供了合理的理论基础;从变分不等式的角度出发,阐述了对应于摩擦约束弹性、弹塑性问题的广义变分不等式理论,首次提出了在应力相容性条件下,它的有限元解具有存在唯一性,进而讨论了其有限元近似及离散解法;基于摩擦约束弹塑性广义变分不等式原理,首次提出了直接广义变分不等式方法,这一方法是直接变分法的合理推广和发展;利用直接广义变分不等式方法对金属压力加工中的平面变形问题、镦粗、挤压等塑性成形问题进行了分析计算,验证了该理论和数值算法的正确性、实用性、精确性和优越性。
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The discrete velocity ordinate method in the kinetic theory of gases is developed and applied to discretize the correspo
借助非定常时间分裂法和无波动无自由参数的NND耗散格式,建立直接求解微观分子速度分布函数的有限差分数值格式;研究并发展可用于离散速度坐标点选取和离散速度空间宏观取矩的高斯─埃尔米特无穷积分方法、等均间隔的牛顿─柯斯复合积分法、以勒让德多项式的根为积分结点的高斯─勒让德数值积分法,并应用于不同马赫数绕流模拟;通过对不同流域一维激波管问题、二维圆柱绕流问题和三维球体绕流的计算研究,并将计算结果与其他途径得到的研究结果诸如DSMC模拟值、N-S解及有关实验数据进行比较分析,创建了一套能有效模拟稀薄流到连续流不同流域气体流动问题简化的统一数值算法研究框架
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Boundary polynomial point interpolation mesh-free method and boundary radial point interpolation mesh-free method were presented, based on polynomial basis and radial basis respectively for transient eddy current analysis, and their interpolation shape functions satisfy the Kronecker delta function and the essential boundary conditions can be directly imposed on the boundary nodes. An example on analyzing transient eddy current of a square metal column was set to prove the validity of the proposed methods, and a comparison on accuracy between BPPIM and BRPIM was analyzed as well.
运用多项式点插值法和径向基点插值法构造形函数,推导了适合于工程电磁场瞬态涡流问题的多项式基点插值边界无单元方法和径向基点播值边界无单元方法,这两种方法的空间插值形函数满足Kronecker delta条件,从而强加边界条件可以直接施加在边界点上,以金属长方柱的瞬态涡流分析作为数值算例,证实了两种方法的正确性和有效性,并对两种基类的点插值法进行了精度分析和比较。
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As an effective method of numerical computation, FEM is widely applied in numerical simulation of metal deformation process.
有限元法作为一种有效的数值计算方法已经被广泛应用于金属成形过程的数值模拟方面,但是有限元分析软件在使用过程中也存在许多问题,例如数值模拟解的精度问题,直接优化设计技术参数的问题。
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Research results indicate that continuous Regional Identification Function is used in nodal virtual flux method, volumn integral and surface integral enhances the convergence and stabilization;using 'put a big number' to deal with the first boundary is faster than 'Remove row and column', the more the first boundary nodes are the more obvious advantage will display;PCG method is quite faster than Crout method to solve equations;it is reliable to use three-dimensional finite element simulation theories to simulate and predict deep foundation pit dewatering in such areas.
研究结果表明,在结点虚流量法及计算体积分和面积分时引入连续的区域识别函数增强了解的收敛性和稳定性;处理已知水头边界的&置大数&法在时间上要比&去行去列&法短一些,定水头边界节点越多,其优越性表现越明显;PCG法比直接解法快很多;三维有限元数值模拟理论用于模拟预测此类地区的深基坑降水具有较高的可信度。
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The main research work of this dissertation is as follows: Based on the chemical reaction engineering theory and the nitrobenzene electroreduction mechanism, the plate and frame electrolyzer was designed and applied to the process of electroreduction nitrobenzene to p-aminophenol. This dissertation measured the residence time distribution data of the electrolyzer by means of the pulse response method and studied the rule of flow pattern along with the current capacity change. Under different conditions ,this dissertation studied the cyclic voltammetry properties of nitrobenzene on different electrodes by means of the dynamic cyclic voltammetry method and the electrode materials applied to the NB electroreduction have been selected primarily.Baseed on the results of cyclic voltammetry tests, this dissertation used p-electrode systems to measure the steady-state- polarization curves of nitrobenzene on different electrodes in H-type diaphragm cell, and obtained each primary factor s influence rule and the exchange current density value of each electrode.And then on the basis of the conclusions of fundamental researchs upword, the effects of influence factors on the the yield of p-aminophenol and the current efficiency,such as electrode material, current density, quantity of electricity circulated, nitrobenzene concentration . sulpuric acid concentration and so on, have been studied in detail in the systems of hign temperature , strong acidity and oxygen-poorthrough a series of electrolysis experiments in this paper.After all using Pb as anode Monel metal as cathode Dupont Nafion 417 cation-exchange membrane as membrane, this dissertation obtained the optimum technological condition: reaction temperature about 85C, current density 500A m-2, sulphuric acid concentration 20%wt.
论文的主要研究工作为:运用化学反应工程理论,结合硝基苯的电还原机理,设计出用于硝基苯直接电还原合成对氨基苯酚实验的板框式电解槽,并利用脉冲响应法测定了该板框式电解槽的停留时间分布数据,研究了流型随流量变化的规律;通过动态循环伏安法研究了硝基苯在不同电极上、不同条件下的循环伏安特性,初步评选出了用于硝基苯电还原的电极材料;结合循环伏安的测定结果,在H型隔膜电解槽中采用三电极体系测定了硝基苯在不同电极上、不同条件下的稳态极化曲线,得到了各主要因素的影响规律及硝基苯在各个电极上电还原的交换电流密度数值;在基础研究结论指导下,采用板框式电解槽,在高温、强酸、贫氧系统中,进行了一系列的电解实验,分别考察了电极材料、电流密度、通电量、硝基苯浓度、硫酸浓度等因素对收率及电流效率的影响,最终选择以蒙乃尔合金电极作为阴极、铅合金为阳极、Dupont Nofion 417阳离子交换膜为隔膜,得到由硝基苯直接电还原制对氨基苯酚的最佳电解工艺条件:反应温度85℃,电流密度500A·m~(-2),硫酸浓度20%wt。
- 推荐网络例句
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But we don't care about Battlegrounds.
但我们并不在乎沙场中的显露。
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Ah! don't mention it, the butcher's shop is a horror.
啊!不用提了。提到肉,真是糟透了。
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Tristan, I have nowhere to send this letter and no reason to believe you wish to receive it.
Tristan ,我不知道把这信寄到哪里,也不知道你是否想收到它。