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增材制造 1

多重物理建模 1

微观结构 1

数据科学 1

显微硬度 1

自组织映射 1

镍基高温合金 1

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A novel algorithm for frequency dependent modeling of ferrite ring and its optimum design to study VFTO behaviors within GIS

Mehrdad MAJIDI, Hamid JAVADI, Moein MANBACHI

《能源前沿（英文）》 2014年第8卷第1期页码 90-100 doi: 10.1007/s11708-013-0286-2

摘要： One of the fundamental issues in gas insulated substations (GIS) which has destructive effects on GIS equipment is the very fast transient over-voltages (VFTOs). This paper models a 400/230 kV substation in order to study the effects of VFTO extensively implemented on EMTP-RV. In addition, the application of ferrite rings for suppressing VFTOs is assessed thoroughly. The main advantage of this paper is its new proposed algorithm according to the ferrite ring frequency dependent modeling that is validated with experimental results. This paper examines the effects of three compositions of the ferrite ring on VFTO suppression. Moreover, it estimates the dimension of the ferrite ring based on the SF6 gas insulation withstand and the maximum effect of ferrite rings on VFTO suppression constraint with the COMSOL multiphysics software. Furthermore, it gains VFTO attenuated percentages due to the installation of the ferrite ring in different GIS nodes. Finally, it analyzes the offered VFTO amendment technique in various GIS switching scenarios.

关键词： comsol multiphysics EMTP-RV ferrite ring gas insulated substations (GIS) transient over-voltage insulation coordination

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Thermo-mechanical simulation of frost heave in saturated soils

《结构与土木工程前沿（英文）》页码 1400-1412 doi: 10.1007/s11709-023-0990-x

摘要： Roads are exposed to various degradation mechanisms during their lifetime. The pavement deterioration caused by the surrounding environment is particularly severe in winter when the humidity and subfreezing temperatures prevail. Frost heave-induced damage is one of the winter-related pavement deterioration. It occurs when the porewater in the soil is exposed to freezing temperatures. The study of frost heave requires conducting a multiphysics analysis, considering the thermal, mechanical, and hydraulic fields. This paper presents the use of a coupled thermo-mechanical approach to simulate frost heave in saturated soils. A function predicting porosity evolution is implemented to couple the thermal and mechanical field analyses. This function indirectly considers the effect of the water seepage inside the soil. Different frost heave scenarios with uniform and non-uniform boundary conditions are considered to demonstrate the capabilities of the method. The results of the simulations indicate that the thermo-mechanical model captures various processes involved in the frost heave phenomenon, such as water fusion, porosity variation, cryogenic suction force generation, and soil expansion. The characteristics and consequences of each process are determined and discussed separately. Furthermore, the results show that non-uniform thermal boundaries and presence of a culvert inside the soil result in uneven ground surface deformations.

关键词： frost heave multiphysics analysis thermo-mechanical approach saturated soils

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基于自组织映射的增材制造中数据驱动式微观组织和显微硬度设计 Article

甘政涛, 李恒阳, Sarah J. Wolff, Jennifer L. Bennett, Gregory Hyatt, Gregory J. Wagner, 曹简, Wing Kam Liu

《工程（英文）》 2019年第5卷第4期页码 730-735 doi: 10.1016/j.eng.2019.03.014

摘要：

为了在镍基高温合金的增材制造（AM）中设计微观组织和显微硬度，本研究提出了一种新的数据驱动方法，该方法结合了物理模型、实验测量和数据挖掘方法。该模拟基于计算热流体动力学（CtFD）模型，可以获得热行为、凝固参数（如冷却速度）和凝固层的稀释率。根据计算出的热信息，可利用经过充分测试的力学模型估算枝晶臂间距和显微硬度。通过实验测定试样的微观结构和显微硬度，与模拟值进行比较验证。为了实现过程-组织-性能（PSP）关系的可视化，模拟及实验数据集被输入到数据挖掘模型——自组织映射（SOM）中。在多目标下，工艺参数的设计窗口可以从可视化映射中得到。这种被提出的方法可用于AM和其他数据密集型工艺过程。过程、组织和性能之间的数据驱动联系可能会有利于在线过程监控控制，从而获得理想的微观组织和力学性能。

关键词：增材制造数据科学多重物理建模自组织映射微观结构显微硬度镍基高温合金