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隐式算法

隐式算法的相关文献在1989年到2021年内共计90篇,主要集中在自动化技术、计算机技术、力学、航空 等领域,其中期刊论文79篇、会议论文8篇、专利文献2445537篇;相关期刊61种,包括科技成果管理与研究、西北工业大学学报、现代电子技术等; 相关会议7种,包括2015年船舶与海洋结构学术会议暨中国钢结构协会海洋钢结构分会成立三十周年纪念学术会议、第十六届全国计算流体力学会议、2012年中国工程热物理学会热机气动热力学学术年会等;隐式算法的相关文献由206位作者贡献,包括王琪、陆启韶、黄克累等。

隐式算法—发文量

期刊论文>

论文:79 占比:0.00%

会议论文>

论文:8 占比:0.00%

专利文献>

论文:2445537 占比:100.00%

总计:2445624篇

隐式算法—发文趋势图

隐式算法

-研究学者

  • 王琪
  • 陆启韶
  • 黄克累
  • 叶正寅
  • 吴琪
  • 招启军
  • 楼梦麟
  • 毛钧杰
  • 王刚
  • 符晓玲
  • 期刊论文
  • 会议论文
  • 专利文献

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    • 代宁; 耿大将; 郭培军; 周顺华; 狄宏规
    • 摘要: 基于Jacobian矩阵的奇异和不收敛特性,分析了弹塑性本构模型的组成和算法.将牛顿?最近点投影法(Newton?CPPM)隐式算法中高度非线性方程组的求解问题转化为求最小值问题,通过采用共轭梯度法求解该最小值来实现对传统隐式算法的改进.最后,以考虑软土结构性的Saniclay模型为例,在单元体分析计算的基础上,考虑不同的应变路径和初始应力状态,对传统隐式算法和改进隐式算法在计算收敛性、计算精度和计算效率方面进行对比,并通过工程算例检验传统隐式算法和改进隐式算法之间的差异.结果表明:相较于传统隐式算法,改进隐式算法能够有效提高计算效率和收敛性.
    • 曹骋; 陈红全
    • 摘要: 发展出一种用于求解欧拉方程的预处理隐式无网格算法.该算法对守恒型欧拉方程进行Weiss-Smith型矩阵预处理,并在无网格点云上离散求解.求解大体是基于传统无网格算法展开的,为此,先对矩阵谱半径、人工耗散项、远场边界条件等受预处理影响的部分进行了具体的讨论.接着,结合LU-SGS算法,通过点云重排与分割,给出了预处理隐式无网格算法的具体实施过程.典型翼型和机翼算例与文献或实验结果进行了验证比较,表明所发展的隐式算法比相应显式算法收敛更快,已从单纯模拟可压缩流动拓展到模拟几乎不可压的低马赫数流.最后,给出了翼身组合体的低马赫数绕流算例,进一步展示出算法处理实用三维气动外形的潜力.
    • XIA Guoqing; LIU Caiyun; CHEN Xinghua; LI Jiaojiao
    • 摘要: 针对锚泊辅助动力定位系统预测控制中的实时性特征,本文选择隐式广义预测控制算法对混合定位船舶控制器进行设计.对于广义预测控制算法滚动优化过程中需引入繁琐的丢备图方程中引起的实时性差问题,采用隐式自校正方法进行了修正.通过利用递推最小二乘法直接辨识控制增量表达式中的参数,减少了计算复杂度,从而满足了控制器的实时性要求.隐式GPC不仅具有传统的GPC算法的优点,而且鲁棒性更好.通过船舶混合定位系统的仿真结果可以看出,隐式GPC算法具有良好的性能,提高了混合定位系统的定位精度和性能.
    • 耿大将; Peijun Guo; 周顺华
    • 摘要: 对于考虑软土结构性的高度非线性弹塑性本构模型,在采用Newton-CPPM隐式算法对模型进行数值实现的过程中容易出现Jacobian矩阵奇异和不收敛问题.为此,本文提出了两种改进隐式算法.考虑到Newton-CPPM隐式算法是局部收敛性算法,因此引入大范围收敛的同伦延拓算法对Newton-CPPM算法的迭代初值进行改进,形成了同伦–Newton-CPPM算法.考虑到Newton-CPPM隐式算法单个迭代步的计算量过大,因此借鉴显式算法的思想提出一种两阶段迭代算法,第一阶段先求出一致性参数,第二阶段采用类似于显示算法的方法进行回代得出状态变量的值.然后,以考虑软土结构性的SANICLAY模型为例,从弹塑性本构模型的组成和算法的特点两个角度分析了引起Jacobian矩阵奇异和不收敛问题的原因,并且在单单元计算的基础上,对全显式算法、传统隐式算法和两种改进隐式算法在计算收敛性、计算精度和计算效率方面进行了对比.最后,将同伦–Newton-CPPM算法和传统隐式算法用于地基承载力多单元计算中,结果表明该算法能够有效地解决Jacobian矩阵奇异和不收敛问题.%Compared with the general constitutive models,the highly nonlinear elasto-plastic constitutive models for structured clays are more complex,which leads to the problems of Jacobian matrix singularity and nonconvergence more easily when the implicit algorithm of Newton-CPPM is used for the numerical implementation.To solve the problems,two implicit algorithms are proposed in this paper.Considering the Newton-CPPM implicit algorithm is a local convergence algorithm,the homotopy continuation algorithm of global convergence is introduced to improve the iterative initial value of the Newton-CPPM algorithm,so the method can be called as homotopy-Newton-CPPM algorithm.Considering that the calculation of every iteration for the Newton-CPPM implicit algorithm is too large,a two-stage iterative algorithm based on the idea of the fully explicit algorithm is presented.The consistency parameter is calculated in the first-stage,taking the consistency parameter as a known quantity and the algorithm similar to the explicit algorithm is used to solve the values of state variables in the second-stage.Then,taking the SANICLAY model that including destructuration as an example,from the two aspects of the composition of the elasto-plastic constitutive model and the characteristics of the algorithm,the reasons for Jacobian matrix singularity and nonconvergence are analyzed.The convergence,accuracy and cost of four algorithms,including the explicit algorithm,traditional implicit algorithm and two kinds of improved implicit algorithms,are compared with reference to the numerical simulations of single element tests.Finally,the homotopy-Newton-CPPM algorithm and the traditional implicit algorithm are applied to the multi-element calculation of subgrade bearing capacity.The results show that the homotopy-Newton-CPPM algorithm can effectively improve convergence and avoid singularity of Jacobian matrix compared with the traditional implicit algorithm.
    • 陈小翠; 杜成斌; 江守燕
    • 摘要: 高应变率载荷作用下金属材料的变形集中于很窄的区域内,即剪切变形局部化.局部化变形带内产生严重的塑性变形,削弱材料的承载能力,甚至导致材料断裂破坏.基于有限元分析软件FEAP (Finite Element Analysis Program),采用混合有限元方法,用Fortran语言编译适用于金属材料在高应变率下的剪切局部化问题的新单元;计算过程中采用与应变、应变率及温度相关的塑性本构关系来描述剪切带现象,同时在能量平衡方程中考虑剪切带形成过程中的热传导作用;同时考虑显式算法与隐式算法的时间离散方法,并将两种算法的结果进行对比.结果表明,虽然剪切带形成过程很短,一般为微秒量级,但剪切带形成过程中的热扩散项与塑性变形产生的热能量级相同,有效地缓解剪切带模拟的网格敏感性;对于金属材料热塑性剪切带问题,为了满足计算精度要求,显式算法需要的时间步太小,计算成本比隐式迭代高很多;而基于该单元采用隐式算法模拟热塑性剪切带问题迭代收敛稳定,计算精度高,且因为考虑了热传导作用,网格敏感性小.
    • 李帛洋; 赵争鸣; 檀添; 杨祎; 蒋烨; 袁立强
    • 摘要: 为解决电力电子系统中的刚性状态方程数值解算困难问题,在后向量化状态系统(BQSS)算法的基础上提出一种后向离散状态事件驱动(BDSED)仿真方法.BDSED方法是隐式的,其关键在于如何选择一组合适的量化函数值组合,使得据此计算出的导数向量能够让各状态变量向其对应的量化函数值趋近.由于在每一步计算中,每一个状态变量下一时刻的量化函数都有两种取值,所以对于复杂高维系统,枚举的方式并不可行;同时各状态变量的量化函数值的确定存在互相耦合、相互制约的关系,导致问题更加困难.为解决该问题,提出一种基于有限状态机的实现方案,并在带非理想器件模型的变换器电路上进行了算例验证.仿真结果表明,基于有限状态机实现的BDSED能高效地选取量化函数值组合,在解算变换器等刚性系统时仿真效率明显优于DSED方法和传统的时间离散刚性解法.%A backward discrete state event driven (BDSED) simulation method based on the backward quantized state system (BQSS) algorithm is proposed in this paper, to solve the difficult problem of rigid state equations in power electronics systems. BDSED method is implicit, and the key point is to select the correct combination of quantization values, which allows the state variables to approach their quantization values. Each state variable has two possible quantization values at each step, thus enumeration is infeasible in complex systems. What's more, taken into account the constraint and mutual coupling between state variables when determining their quantization values, the question becomes quite difficult. Thus, an implementation approach of BDSED based on finite state machine is proposed in this paper. The simulation algorithm is tested in a converter circuit with non-ideal device models. Simulation results show that BDSED based on finite state machine can efficiently select the combination of quantization values, and its simulation efficiency is obviously higher than DSED as well as traditional time-slicing ODE methods when solving stiff systems such as power converters.
    • 阚子云; 彭海军; 陈飙松
    • 摘要: 弹簧-阻尼-作动器(spring-damper-actuator,SDA)是多体系统中常见的力元,在工程领域中有着广泛的应用.采用绝对坐标方法建立的多体系统动力学控制方程通常是复杂的非线性微分-代数方程组.为了保证数值解的精度和稳定性,通常需要采用隐式算法求解动力学方程,而雅可比矩阵的计算在隐式数值求解过程中至关重要.对于含有SDA的多体系统,SDA造成的附加雅可比矩阵是与广义坐标和广义速度相关的高度非线性函数.目前的很多研究工作专注于广义力向量的计算,然而对附加雅克比矩阵的计算则少有关注.针对含SDA的多刚体系统进行动力学分析,首先基于Newmark算法研究其在动力学方程求解中的雅可比矩阵的构成形式;然后推导SDA的广义力向量对应的附加雅可比矩阵,其中包括广义力向量对广义坐标和对广义速度的偏导数矩阵.最后通过两个数值算例研究附加雅可比矩阵对动力学分析收敛性的影响;数值分析表明:当SDA的刚度、阻尼和作动力数值较大时,SDA导致的附加雅可比矩阵对数值解的收敛性有重要影响;当考虑SDA对应的附加雅可比矩阵时,动力学分析可以以较少的迭代步实现收敛,从而减少分析时间.%The spring-damper-actuator (SDA) is a common force element in multibody system and widely used in the field of engineering. The governing equations of multibody dynamic system established by absolute coordinate methods are differential-algebraic equations which are usually nonlinear and complex. To ensure the stability and accuracy of the numerical solutions, the implicit algorithms are commonly used to solve the dynamic equations. While the calculations of Jacobian matrices are the crucial process in implicit algorithms. For a multibody system containing the SDA, the addi-tional Jacobian matrices induced by the SDA are highly nonlinear functions of the generalized coordinates and generalized velocities. A lot of current research works focus on the calculation of generalized force vector, however the calculations of additional Jacobian matrices are less concerned. This paper focuses on dynamic analysis of multi-rigid-body systems containing the SDA. Firstly, the construction of the accurate Jacobian matrices in solving the dynamic equations is investi-gated based on the Newmark algorithm. Then, the additional Jacobian matrices relating to the generalized force vector of the SDA are analytically derived. These matrices consist of the partial derivative of generalized force vector with respect to the generalized coordinates and the generalized velocities. Finally, the influence of additional Jacobian matrices on the convergence of dynamic analysis is investigated via two numerical examples. The numerical results indicate that when the values of stiffness, damping and active force are large, the additional Jacobian matrices induced by the SDA have a significant influence on the convergence of dynamic analysis. When the additional Jacobian matrices induced by the SDA are taken into account, the dynamic analysis can achieve convergence with less iteration steps and the computational time thus can be reduced.
    • 蔡永宾
    • 摘要: 使用HyperWorks软件建立了某乘用车车门有限元模型,对车门外板进行静态分析、屈曲分析和约束模态分析,确定出车门表面刚性分析中的加载点位置.对车门进行表面刚性分析,得出该车门存在表面刚性不足的问题,通过对车门表面刚性薄弱的地方进行结构强化,提高了车门表面刚性性能.
    • 梁涛; 葛群
    • 摘要: 广义预测控制算法具有控制效果好、鲁棒性强和模型要求低等优点.分析广义预测控制原理及其隐式算法,利用预测信息对控制增量的选取策略进行了改进,并针对该算法在具有大滞后和时变性的电站锅炉过热汽温控制过程中的应用进行了仿真研究.最后通过仿真结果验证了该算法的优越性和可行性.
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