日负荷数据聚类是实现用户用电特性分析的重要方式。用于聚类的降维采样数据的指标权重会影响聚类结果,因此提出一种基于CRITIC赋权的奇异值分解(singular value decomposition,SVD)降维方法C-SVD与改进加权模糊C均值聚类(fuzzy C-means...日负荷数据聚类是实现用户用电特性分析的重要方式。用于聚类的降维采样数据的指标权重会影响聚类结果,因此提出一种基于CRITIC赋权的奇异值分解(singular value decomposition,SVD)降维方法C-SVD与改进加权模糊C均值聚类(fuzzy C-means,FCM)算法相结合的日负荷数据聚类方法,同时针对传统FCM易受初始聚类中心影响的问题,提出一种自适应确定初始聚类中心的密度‒距离中心点选择(density-distance centersr selection,DDCS)方法。首先,采用SVD对负荷数据进行降维处理;其次,使用CRITIC赋权法对降维指标进行权重配置;然后,使用DDCS法确定初始聚类中心;最后,使用加权FCM算法对负荷数据进行聚类。仿真算例表明,与传统方法相比,所提方法鲁棒性强,能够明显提升负荷数据聚类结果的准确性。展开更多
The finite cell method （FCM） combines the high-order finite element method （FEM） with the fictitious domain approach for the purpose of simple meshing. In the present study, the FCM is used to the Prandtl-Reuss fl...The finite cell method （FCM） combines the high-order finite element method （FEM） with the fictitious domain approach for the purpose of simple meshing. In the present study, the FCM is used to the Prandtl-Reuss flow theory of plasticity, and the results are compared with the h-version finite element method （h-FEM）. The numerical results show that the FCM is more efficient compared to the h-FEM for elasto-plastic problems, although the mesh does not conform to the boundary. It is also demonstrated that the FCM performs well for elasto-plastic loading and unloading.展开更多
In this work, a design procedure extending the B-spline based finite cell method into shape optimization is developed for axisymmetric solids involving the centrifugal force effect. We first replace the traditional co...In this work, a design procedure extending the B-spline based finite cell method into shape optimization is developed for axisymmetric solids involving the centrifugal force effect. We first replace the traditional conforming mesh in the finite element method with structured cells that are fixed during the whole design process with a view to avoid the sophisticated re-meshing and eventual mesh distortion.Then, B-spline shape functions are further implemented to yield a high-order continuity field along the cell boundary in stress analysis. By means of the implicit description of the shape boundary, stress sensitivity is analytically derived with respect to shape design variables. Finally, we illustrate the efficiency and accuracy of the proposed protocol by several numerical test cases as well as a whole design procedure carried out on an aeronautic turbine disk.展开更多
基金supported by the Alexander von Humboldt Foundation
文摘The finite cell method （FCM） combines the high-order finite element method （FEM） with the fictitious domain approach for the purpose of simple meshing. In the present study, the FCM is used to the Prandtl-Reuss flow theory of plasticity, and the results are compared with the h-version finite element method （h-FEM）. The numerical results show that the FCM is more efficient compared to the h-FEM for elasto-plastic problems, although the mesh does not conform to the boundary. It is also demonstrated that the FCM performs well for elasto-plastic loading and unloading.
基金supported by the National Natura Science Foundation of China (Grant 51275424)973 Program (Gran2011CB610304)+1 种基金Research Fund for the Doctoral Program of Higher Education of China (Grant 20126102130003)the opening project (Grant KFJJ13-6M) of the State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology)
文摘In this work, a design procedure extending the B-spline based finite cell method into shape optimization is developed for axisymmetric solids involving the centrifugal force effect. We first replace the traditional conforming mesh in the finite element method with structured cells that are fixed during the whole design process with a view to avoid the sophisticated re-meshing and eventual mesh distortion.Then, B-spline shape functions are further implemented to yield a high-order continuity field along the cell boundary in stress analysis. By means of the implicit description of the shape boundary, stress sensitivity is analytically derived with respect to shape design variables. Finally, we illustrate the efficiency and accuracy of the proposed protocol by several numerical test cases as well as a whole design procedure carried out on an aeronautic turbine disk.
