共查询到19条相似文献，搜索用时 140 毫秒
1.
2.
3.
利用UG、ADAMS在各自领域中的优势,将二者有机结合起来进行虚拟设计。以6300型柴油发动机曲轴连杆机构为研究对象,介绍了虚拟设计的流程与不同软件之间的数据传递,应用UG软件建立曲轴连杆机构的仿真模型,实现设计的可视化;采用ADAMS进行动力学仿真分析,直观地显示曲轴连杆机构的运动过程,为提高发动机的整体设计提供理论依据。 相似文献
4.
科学技术发展至今,对于内燃机的应用领域已经越来越广泛,与此同时,要求也越来越高。发动机中最主要的一个零件是曲轴,所以它是决定发动机质量的关键因素。发动机想要在原有的质量及功能上做出飞跃,就只能从曲轴下手,所以近年来,曲轴的结构设计越来越复杂。文章主要从建模的角度分析了发动机曲柄连杆机构动力学特征。 相似文献
5.
曲轴作为发动机的重要运动部件,其结构性能直接影响着发动机的可靠性和使用寿命。以Pro/E建立的直列四缸发动机曲轴为基础,利用ANSYS有限元法对曲轴的静力和模态分析。通过改变轴颈圆角半径大小、曲柄销长度、曲柄臂厚度、轴颈重叠度的结构参数,确定了各参数对轴颈圆角最大应力的影响。模态分析结果表明,曲轴在低阶次频率下以弯曲为主,最大振型位移出现在曲轴两端轴颈处,在高阶次频率下以扭转为主。分析结果为曲轴的优化设计和动力学分析提供了指导。 相似文献
6.
7.
8.
9.
在曲柄、连杆、缸径等重要参数不变的情况下,仅改变其曲轴中心的位置,能提高发动机的动力性和经济性,国外有该种发动机应用报道,国内也有专利,但对其动力性、经济性提高的原因及理论依据国内外都未见分析报道。本文应用运动学、动力学、热力学和发动机理论等相关知识,对曲轴偏移式发动机的动力性、经济性及可靠性方面进行理论分析,结论是偏置式发动机比中心式发动机的动力性及经济性都得到提升;同时也带来一些负面影响,经过工艺改进可以克服。 相似文献
10.
11.
This paper is concerned with the decentralized event-triggered H∞ control for switched systems subject to network communication delay and exogenous disturbance. Depending on different physical properties, the system state is divided into multiple communication channels and decentralized sensors are employed to collect signals on these channels. Furthermore, decentralized event-triggering mechanisms (DETMs) with a switching structure are proposed to determine whether the sampled data needs to be transmitted. In particular, an improved data buffer is presented which can guarantee more timely utilization of the sampled data. Then, with the proposed DETMs and data buffer, a time-delay closed-loop switched system is developed. After that, sufficient conditions are presented to guarantee the H∞ performance of the closed-loop switched system by utilizing the average dwell time and piecewise Lyapunov functional method. Since the event-triggered instants and the switching instants may stagger with each other, the influence of their coupling on the H∞ performance analysis is systematically discussed. Subsequently, sufficient conditions for designing the event-triggered state feedback controller gains are provided. Finally, numerical simulations are given to verify the effectiveness of the proposed method. 相似文献
12.
Zhichao Jiang Yan Zhao Xueli Bai Zexian Zhang 《Journal of The Franklin Institute》2021,358(7):3609-3632
In this paper, a delayed feedback controller with the delay-dependent coefficient is introduced into a multiple delay phytoplankton-zooplankton system. For uncontrolled system, choosing delays as the bifurcation parameters, we prove that Hopf bifurcation can occur when the delays change and cross some values. Then, the delays are still chosen as the bifurcation parameters to research the dynamic behaviors of the controlled system. Under this control mechanism, the onset of Hopf bifurcation can be delayed by selecting the appropriate control parameters and the stability domain can be extended as feedback gain (the decay rate) decreases (increases), and the influence of the decay rate cannot be ignored. Furthermore, using the crossing curve methods, the stable changes of equilibrium in two delay plane can be obtained. Some numerical simulations are given to verify the correctness and validity of the delayed feedback controller in the bifurcation control. 相似文献
13.
主要运用常规和拉伸分子动力学模拟方法,研究β-淀粉样多肽的构象变化过程、乙酰胆碱酯酶和其抑制剂石杉碱甲的结合与解离过程,以及烟碱乙酰胆碱受体的离子门控构象变化过程,从而为老年痴呆症的病变机理,阐述和设计发现新的抗老年痴呆药物提供线索. 相似文献
14.
非均质渗透介质纵向弥散度数值模拟 估算法适宜性探析 总被引：1，自引：0，他引：1
介绍了地下水溶质迁移转化模拟软件MT3DMS中的数值解法MOC、MMOC、HMOC和高阶TVD等的基本原理,分析比较了不同解法所获得的地下水污染时空分布模拟结果的质量误差以及纵向弥散度模拟计算结果异同,并进一步探讨了网格大小与污染源质量浓度对模拟结果的影响等.展现了通过数值模拟估算纵向弥散度的基本过程及其适宜性,重点探析了不同数值解法模拟估算弥散度的适用性. 相似文献
15.
The stochastic minimum-variance pseudo-unbiased reduced-rank estimator (stochastic MV-PURE estimator) has been developed to provide linear estimation with robustness against high noise levels, imperfections in model knowledge, and ill-conditioned systems. In this paper, we investigate the theoretical performance of the stochastic MV-PURE estimator under varying levels of additive noise. We prove that the mean-square-error (MSE) of this estimator in the low signal-to-noise (SNR) region is much smaller than that obtained with its full-rank version, the minimum-variance distortionless estimator, and the gap becomes larger as the noise level increases. These results shed light on the excellent performance of the stochastic MV-PURE estimator in highly noisy settings obtained in simulations so far. Furthermore, we extend previous numerical simulations to show how the insight gained from the results of this paper can be used in practice. 相似文献
16.
Towards plug and play filling of microfluidic devices by utilizing networks of capillary stop valves
Robust bubble-free priming of complex microfluidic chips represents a critical, yet often unmet prerequisite to enable their practical and widespread application. Towards this end, the usage of a network of capillary stop valves as a generic design feature is proposed. Design principles, numerical simulations, and their application in the development of a microfluidic cell culture device are presented. This chip comprises eight parallel chambers for the assembly and cultivation of human hepatocytes and endothelial cells. The inlet channel divides into cell chambers, after which the flows are reunited to a single chip outlet. Dimensions and geometry of channels and cell chambers are designed to yield capillary burst pressures sequentially increasing towards the chip outlet. Thus, progress of liquid flow through the device is predefined by design and enclosure of air bubbles inside the microfluidic structures is efficiently avoided. Capillary stop valves were designed using numerical simulations. Devices were fabricated in cyclic olefin polymer. Pressure during filling was determined experimentally and is in good agreement with data obtained from simulation. 相似文献
17.
本文将技术邻近性引入创新超网络的演化动态研究,基于专利技术结构给出了企业间技术邻近性的度量方法,分析了创新超网络的技术邻近择优连接机制与超度择优连接机制,并结合超边增长机制构建了技术邻近动态下的创新超网络演化模型。进一步,以新能源汽车行业为例,对创新超网络的数值仿真和实证分析进行了比较研究。不同演化机制下的创新超网络演化动态仿真和新能源汽车创新超网络的实证数据比较结果表明：技术邻近择优连接和超度择优连接的共同作用导致企业创新超网络最终演化为具有无标度性和高集聚性特征的网络;技术邻近择优连接机制的作用越大,创新超网络内企业的技术创新水平越均衡;超度择优连接机制的作用越大,创新超网络的无标度性和小世界性越显著。 相似文献
18.
Qiankun Song 《Journal of The Franklin Institute》2008,345(1):39-59
In this paper, the discrete-time fuzzy cellular neural network with variable delays and impulses is considered. Based on M-matrix theory and analytic methods, several simple sufficient conditions checking the global exponential stability and the existence of periodic solutions are obtained for the neural networks. Moreover, the estimation for exponential convergence rate index is proposed. The obtained results show that the stability and periodic solutions still remain under certain impulsive perturbations for the neural network with stable equilibrium point and periodic solutions. Some examples with simulations are given to show the effectiveness of the obtained results. 相似文献
19.
Density functional theory∕molecular dynamics simulations were employed to give insights into the mechanism of voltage generation based on a water-filled single-walled boron-nitrogen nanotube (SWBNNT). Our calculations showed that (1) the transport properties of confined water in a SWBNNT are different from those of bulk water in view of configuration, the diffusion coefficient, the dipole orientation, and the density distribution, and (2) a voltage difference of several millivolts would generate between the two ends of a SWBNNT due to interactions between the water dipole chains and charge carriers in the tube. Therefore, this structure of a water-filled SWBNNT can be a promising candidate for a synthetic nanoscale power cell as well as a practical nanopower harvesting device. 相似文献