Modeling and control of the pulley buffer system of arresting cable for shipboard aircraft based on magneto-rheological fluid

Taking the MK7-3 of USA hydraulic buffer arresting device as the research subject, the dynamical model for the shipboard aircraft arresting system is established, and the magneto-rheological (MR) damper is applied to pulley shock absorbers for shipboard aircraft block system. Due to the effect of the MR damper has not been known completely and so far MR damper model has not been defined, we use a set of characteristic test of the MR damper, through the process of parameters identification, to establish the dynamical model for the MR damper based on the Bingham plastic model. Then, the fuzzy control rules are designed, the buffer control for the pulley buffer of shipboard aircrafts is completed in touchdown moment based on MR technology. Compared with blocking device of hydraulic pulley buffer in the same condition, the simulations results show that the proposed MR pulley buffer can effectively recognize the impact energy for shipboard block system and reduce the pull peak of arresting cable. It improves significantly safety during landing of the air vehicles and lowers the risk of accidents.     

桥梁板式橡胶支座的性能特点及试验检测

主要介绍了公路桥梁板式橡胶支座类型及结构、性能特点和用途，提出了橡胶支座生产和试验检测中存在的问题以及质量隐患。     

数据挖掘在本科教学评估中的应用

数据挖掘是目前信息领域和数据库技术的前沿研究课题。关联规则技术是数据挖掘的最重要的组成部分之一,它用于发现大量数据中项集之间的有意义的关联和相关联系。在给出教学评估数据挖掘系统的框架之后,使用相关数据进行关联规则算法的实验,对结果进行初步分析,其得出的结论对高校教学评估和教学工作都具有一定的指导意义。     

浅谈沥青路面平整度指标的施工控制

新时期重点工程建设项目单位档案管理是关键，中介绍了重点工程档案管理的重要性，管理中存在的问题及解决的办法。     

Impact arresting process mechanical modeling and sliding model buffer control based on magneto-rheological fluid

The research on the form and control method of impact load arresting buffer has been an active topic in the field of buffer arresting system (BAS). It becomes significant on reducing the weight of arresting system, improving the hindered efficiency, and guaranteeing the security of BAS. The hydraulic hindered device of impact load is currently used in BAS. There are some problems. For example, the system needs large power sources. However, once the power of active hydraulic control system is turned off, there arise unpredictable security risks. An arresting form of semi-active control based on magneto-rheological damper (MRD) is proposed, and the mechanical model of the BAS is established. Meanwhile, the state equation of impact load BAS is established according to the characteristics of impact load buffer arresting, and its sliding model buffer control is achieved. Due to the chattering characteristic of the output signal of sliding mode controller, the method to prevent chattering is designed based on short-term energy and zero-crossing rate detection. For the model and chattering suppression of sliding model buffer control algorithms, simulation results show that the proposed state equation and the arresting model are reasonable, and the design of semi-active control algorithm is effective. On the condition of the buffer control system requirement and the accuracy, the proposed algorithms effectively control the chattering of sliding mode control algorithms, and improve the security of the BAS.     

Research on modeling and fuzzy control of magneto-rheological intelligent buffer system for impact load

So far the magneto-rheological (MR) effect mechanism of MR damper has not been known completely, especially in the impact load, and the problem becomes more complicated and difficult for analyzing. A set of characteristic tests and parameters?? identification are made to the MR damper by the experimental platform. The dynamical model of the damper is constructed based on the Bingham plastic model, and the buffer control strategy of aircraft undercarriage based on MR technology is established. Finally, the fuzzy control algorithm is applied to the process of automatic control for landing buffer of aircraft undercarriage. The simulation results show that the proposed MR damper pulley buffer can effectively recognize the impact energy. The research has a better application in the engineering.     

谈桥梁工程对混凝土材料施工及使用性能的要求

主要对桥梁在施工和使用环境中对混凝土性能的要求进行了阐述。同时，对影响混凝土耐久性的因素作了分析。