分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2024-02-07 合作期刊: 《应用力学学报》
摘要: 碰撞过程凭借瞬时冲击模型得以简化,但采用经典的Newton恢复系数模型为计算带来了误差。本研究引入修正的恢复系数模型取代经典的Newton恢复系数模型,预测了一类宽带噪声激励下双边碰撞振动系统的随机动力学响应。位移的碰撞条件借助自由振动系统被转化为能量的碰撞条件。根据系统的能量水平,系统的运动可被分为双边碰撞和无碰撞振动两类。进一步地,两类运动的平均漂移系数和扩散系数可借助能量包线随机平均法求解获得。在此基础上,建立并求解对应的 Fokker-Plank-Kolmogorov(FPK)方程,进而得到系统的稳态响应。最后,将所提方法应用于 Duffing 振子,讨论了屈服速度、挡板间距和噪声激励对响应的影响,并用蒙特卡罗模拟验证了所述方法的有效性。
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2024-02-07 合作期刊: 《应用力学学报》
摘要: 海洋拖曳系统是典型的刚柔多体系统。需要指出的是,到目前为止,绝大多数的关于海洋拖曳缆体系统的动力学问题研究都没有非常充分地考虑到阻尼的作用。但在海洋拖曳系统的结构动力学分析中,特别是拖缆回转过程中的动态响应分析中,阻尼的作用是不可忽略的。且由于阻尼的存在,拖缆的模态特性也会呈现出高度的复杂性。为探究瑞利阻尼在拖缆回转过程中的影响,基于凝集质量法对瑞利阻尼的在拖缆系统中的表达形式进行了进一步的整理与分解,并对各个阻尼分量的影响进行了归纳总结,得到了一些较为通用性的结论,对于实际海上拖曳作业有一定的指导意义。
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2024-02-07 合作期刊: 《应用力学学报》
摘要: 空间结构的在轨展开涉及到复杂的高维强非线性动力学问题,这些动力学问题的建模及仿真技术是航天动力学领域的难题,也是对在轨展开过程施加控制的前提条件。本研究以IKAROS太阳帆在轨第一阶段展开过程为例,基于哈密顿变分原理,建立中心刚体-主动伸长柔性梁耦合动力学模型; 采用保结构分析方法,关注动力学系统的局部动力学行为,在恒定转矩驱动和恒定功率驱动两种工况条件下,对IKAROS太阳帆第一阶段展开过程进行仿真; 发现两种工况条件下的中心刚体转动角速度演化规律差别显著,恒定转矩做功将导致中心刚体的转动稳定性变差,同时,恒定功率驱动工况下,IKAROS太阳帆第一展开阶段节能效果较好。
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2024-02-07 合作期刊: 《应用力学学报》
摘要: 提出了一种基于主成分分析的斜拉桥拉索损伤识别方法来实现斜拉索损伤识别。该方法首先采集移动荷载激励桥面时拉索结构的加速度响应,然后采用主成分分析法对时域信号进行降维处理,提取降维后信号的统计学数据,结合D-S证据理论构造多阶统计矩融合指标进行识别。以天津永和桥为例,利用有限元进行数值模拟,分别针对斜拉索损伤程度、荷载质量、荷载移动速度对损伤识别精度的影响进行了探究。分析结果表明,所提方法具有良好的识别效果,有较好的噪声鲁棒性。
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2022-11-17 合作期刊: 《Electrical & Electronic Engineering Research》
摘要:This article is fully combed the related literature, the application of big data in the archive management innovation with a thorough system of literature analysis, and obtained from file data acquisition, data transmission, data storage, data archives utilization, staff training and safety archives construction aspects of the need to create a file management system based on big data applications. And Finally, this article analyzes the archival management innovation practice and its effect based on big data application in China, and draws the corresponding value conclusion.
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2022-11-17 合作期刊: 《Electrical & Electronic Engineering Research》
摘要:In order to improve the quality of photovoltaic power injected into the grid, a high-voltage flexible direct current (Voltage Source Converter-High Voltage Direct Curren, VSC-HVDC) grid-connected scheme based on a micro-synchronous phasor measurement unit (μPMU) coordinated control strategy is proposed. The four-terminal topology of photovoltaic power plants connected to the grid via VSC-HVDC is designed, and two photovoltaic power plants are connected to the grid via VSC-HVDC model using Matlab/Simulink simulation software to simulate when the light intensity is changed, the photovoltaic power plant is out of operation and the grid voltage occurs In the case of sudden changes, the system voltage, power, and AC side frequency can still maintain stable operation, which verifies the feasibility and effectiveness of the transmission scheme, and improves the stability and power quality of the power grid.
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2022-11-17 合作期刊: 《Electrical & Electronic Engineering Research》
摘要:
In order to improve the convergence of multi-objective differential evolution (DEMO) algorithm while ensuring well distribution, a new method of center mutation-based DEMO (CM-DEMO) is proposed. Firstly, the form of mutation is improved, the center of the population in the current generation is taken as a base vector, and then the direction of difference vector is determined according to the fitness value of the three random vectors of individuals, secondly, the strategy of adaptive crossover probability is given, the crossover probability is determined according to the distribution of fitness value in the population. Test of benchmark functions show that CM-DEMO algorithm has faster convergence rate. Finally, CM-DEMO is applied to environmental economic dispatch of power system. Compared with other methods, the simulation results obtained demonstrate the feasibility and effectiveness of the proposed algorithm for solving the problem.
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2022-11-17 合作期刊: 《Electrical & Electronic Engineering Research》
摘要:In oil and gas exploration and mineral resource exploration, rock sample identification plays an immeasurable role due to its strong operability. Besides the methods of identifying rock samples by gravity, magnetism, remote sensing, electromagnetics, etc. a new way is to establish an automatic identification and classification model of rock samples by using image deep learning methods. This paper uses the transfer learning method to build a deep convolutional neural network model to realize the automatic classification and recognition of rock samples. First, the original data is preprocessed to ensure that it can be better used for model training. Then, based on the deep learning tool framework TensorFlow, this article uses the transfer learning method to migrate the Inception-V3 deep convolutional neural network model. To be trained in the preprocessed target data set, and improve the learning effect of the target task, so that more reasonable image features can be extracted, until it is trained into a neural network model in the target field, and the rock sample can be better classified.
分类: 动力与电气工程 >> 动力与电气工程其他学科 提交时间: 2022-11-16 合作期刊: 《Electrical & Electronic Engineering Research》
摘要:
It is obvious that the modern agriculture needs the support of modern finance. The agricultural credit guarantee system, is an important means to promote the financial capital into the agriculture industry, and to solve its financing difficulties and its high cost. The designing and application of agricultural guarantee digital system platform will not only be beneficial to accelerate transformation and promotion of the mode of agricultural development, but also be positive significance on the steady growth, promoting the reform, restructuring and livelihood. This paper summarizes the relevant literatures on agricultural guarantee system, designs and develops a set of agricultural guarantee digital system platform based on the application of blockchain and big data technology, and finds it achieves a lot of benefits and good effects based on the practice in China.