共查询到19条相似文献,搜索用时 712 毫秒
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本文针对无缝线路容易发生胀轨跑道和断轨的问题,提出了一种全新的轨道结构形式-自适应无缝线路。阐述了自适应无缝线路的概念及特点,论述了自适应无缝线路进行“自适应”的工作原理。根据设计思想建立了自适应无缝线路结构优化设计模型,并通过求解得到了具体的结构设计方案。 相似文献
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基于EEP (单元能量投影)超收敛计算的自适应有限元法,已对一系列问题取得成功,但其自适应特性尚缺乏相关研究。该文以二阶常微分方程为模型问题,同时考察基于EEP和SPR (超收敛分片恢复)超收敛解的自适应分析方法,与有限元最优网格进行了比较分析,进而提出反映自适应有限元收敛特性的估计式,并给出了自适应收敛率β的定义。该文给出的数值试验表明:采用m次单元,对于解答光滑的问题,SPR法与EEP法均可有效用于自适应求解,其位移可按最大模获得m+1的自适应收敛率;对于奇异因子为α(<1)的奇异问题,SPR法失效,而基于EEP法的自适应求解,其位移按最大模可获得m+α的自适应收敛率,远高于α的常规有限元收敛率。 相似文献
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有限元后处理中超收敛计算的EEP(单元能量投影)法以及基于该法的自适应分析方法对线性ODE(常微分方程)问题的求解已经获得了全面成功,也推动了非线性ODE问题自适应求解的研究。经过研究,已经实现了一维有限元自适应分析技术从线性到非线性的跨越,该文意在对这方面的进展作一简要综述与报道。该文提出一种基于EEP法的一维非线性有限元自适应求解方法,其基本思想是通过线性化,将现有的线性问题自适应求解方法直接引入非线性问题求解,而无需单独建立非线性问题的超收敛计算公式和自适应算法,从而构成一个统一的、通用的非线性问题自适应求解算法。该文给出的数值算例表明所提出的算法高效、稳定、通用、可靠,解答可逐点按最大模度量满足用户给定的误差限,可作为先进高效的非线性ODE求解器的核心理论和算法。 相似文献
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混凝土骨料模型是由骨料、砂浆基体以及界面层组成的三相复合材料。由于骨料形状的复杂性及各相材料性质差异悬殊,需要采用自适应有限元方法进行有效数值计算与模拟。p型自适应有限元法通过自适应提高基函数的阶次来改善各骨料界面处数值解精度,具有对网格质量要求不高、前处理工作量较少以及阶谱性等优点。该文首先基于ANSYS软件生成了含量可达60%以上的几种复杂形态的二维骨料几何模型;然后,设计和分析了一种基于"分区分级"局部误差控制的p型自适应有限元法,并将其应用于几类典型骨料模型的线性及非线性有限元分析中。数值结果表明,该文设计的p型自适应有限元法对求解混凝土骨料模型是非常有效的,可大大提高各骨料界面处数值解的计算精度,为进行混凝土材料的相关力学性能分析提供了一种高效计算方法。 相似文献
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为了提升整车路噪、平顺性以及疲劳耐久综合性能,构造了序列近似多目标优化方法,结合虚拟试验场(virtual proving ground, VPG)技术对轮胎参数进行了优化设计。采用径向基函数代理模型建立了CDTire轮胎模型关键物理参数与整车多学科性能VPG仿真输出响应的显式数学关系,基于多目标粒子群优化算法与自适应补点方法持续更新代理模型迭代求解逐步逼近真实Pareto前沿。通过设计变量分类建立2步法优化模型,求解匹配轮胎模型参数后,车辆关键测点的全频段噪声均方根、最大振动加速度均值及疲劳损伤均值分别降低了1.6%,10.4%及3.8%,优化效果显著。 相似文献
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In multi-objective optimization computing, it is important to assign suitable parameters to each optimization problem to obtain better solutions. In this study, a self-adaptive multi-objective harmony search (SaMOHS) algorithm is developed to apply the parameter-setting-free technique, which is an example of a self-adaptive methodology. The SaMOHS algorithm attempts to remove some of the inconvenience from parameter setting and selects the most adaptive parameters during the iterative solution search process. To verify the proposed algorithm, an optimal least cost water distribution network design problem is applied to three different target networks. The results are compared with other well-known algorithms such as multi-objective harmony search and the non-dominated sorting genetic algorithm-II. The efficiency of the proposed algorithm is quantified by suitable performance indices. The results indicate that SaMOHS can be efficiently applied to the search for Pareto-optimal solutions in a multi-objective solution space. 相似文献
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A cooling tower is an imperative component of industrial plants. The minimization of energy related expenses is critical for conservation of resources and energy savings. Hence, the present study explores the use of an improved Jaya algorithm called self-adaptive Jaya algorithm for optimal design of cooling tower from economic facets. In this work, six different examples are considered in the design optimization of mechanical draft cooling tower. Various researchers have attempted the same mathematical models by using different methods like Merkel method, Poppe method and artificial bee colony (ABC) algorithm. The results achieved by using the proposed self-adaptive Jaya algorithm are compared with the results achieved by using the Merkel method, Poppe method, ABC algorithm and basic Jaya algorithm. The proposed self-adaptive Jaya algorithm determines the population size automatically and the user need not tune the population size. The proposed self-adaptive Jaya algorithm is proved better as compared to the other optimization methods with respect to achieving the optimal value of the objective function at less computational effort. 相似文献
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动态联盟伙伴选择的一种自适应遗传算法 总被引:7,自引:0,他引:7
针对动态联盟伙伴选择优化问题,提出一种自适应遗传算法用来求解此类问题。该算法设计了自适应交叉和变异概率,在遗传过程中可以根据适应度自动选择,从而使群体中每个个体对环境的变化具有自适应调节能力;所设计的自适应变异概率可以避免算法的早熟现象;遗传过程中,通过保持迭代过程中的最优解,加快了搜索速度,并保证了收敛于全局最优解。通过算例,证实了该算法的有效。 相似文献
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The present work demonstrates a new variant of the harmony search (HS) algorithm where bandwidth (BW) is one of the deciding factors for the time complexity and the performance of the algorithm. The BW needs to have both explorative and exploitative characteristics. The ideology is to use a large BW to search in the full domain and to adjust the BW dynamically closer to the optimal solution. After trying a series of approaches, a methodology inspired by the functioning of a low-pass filter showed satisfactory results. This approach was implemented in the self-adaptive improved harmony search (SIHS) algorithm and tested on several benchmark functions. Compared to the existing HS algorithm and its variants, SIHS showed better performance on most of the test functions. Thereafter, the algorithm was applied to geometric parameter optimization of a friction stir welding tool. 相似文献
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目的 针对数字化生产车间工位物料需求时间的不确定,导致物料配送不准确、不及时的问题,提出一种动态物料配送策略。方法 首先,根据工位关联度和变动时间窗确定实时的配送工位和协同配送工位,设计基于工位排序的动态物料配送路径优化策略。其次,建立以配送成本和时间窗偏离惩罚成本综合最小为目标函数的数学模型。最后,提出并采用系统动力学仿真与蚁群遗传融合算法联合的方法对模型进行求解。结果 模拟算例表明,与静态物料配送优化策略相比,该策略的平均时间成本减少率为30.1%,平均库存减少率为14.86%。结论 该策略能够根据动态时间窗确定配送工位和协同工位,并实时调整配送顺序,实现物料配送的动态自适应性调整,降低总配送成本。融合算法在迭代次数、收敛性、最优解质量方面有明显优越性。 相似文献
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基于MDR-TDMA(Multi-service Dynamic Reservation-TDMA)的无线ATM多址接入控制协议包括两个主要的过程,即请求报文的信息时隙的分配过程,对于前者,通过基于帧的自适应伪贝叶斯ALOHA算法,在保证请求报文最优吞吐率的条件下,实现了不同优先级的请求报文接入。对于后者,着重分析了以视频会议为模型的VBR业务的带宽分配,提出了一种新的带宽分配方法-Minmax算法,并将它的仿真结果与线性比例算法进行比较。 相似文献
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合理的等效电路模型及准确的模型参数对蓄电池荷电状态(SOC)的准确估计具有重要影响。针对蓄电池三阶Thevenin等效电路模型,基于改进蚁狮优化算法,提出了一种模型参数辨识方法。引入混沌Logistic映射初始化,使初始化群体遍及解空间,有利于寻找全局最优解;引入自适应惯性权重加随机柯西变异策略,有效提高了算法收敛速度;引入精英反向学习策略,有效提高了群体的多样性,避免算法陷入局部最优解。5个测试函数的测试结果表明:相比于蚁狮优化算法、粒子群算法与樽海鞘优化算法,改进蚁狮优化算法收敛速度更快,精度更高。对蓄电池三阶Thevenin等效电路模型进行参数辨识,结果表明:改进蚁狮优化算法相比蚁狮优化算法具有更高的辨识精度。 相似文献
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A mathematical model of production planning for a multiproduct, multistage produetionaystom (production equation, transition equation and objective function) was constructed in order to derive the optimal decision rule to be adapted to demand fluctuation. With this model the optimal solution and the computational algorithm were determined by functional space approach. With use of this algorithm, a numerical example of optimal production planning was solved. 相似文献