海洋核动力平台疲劳寿命评估

针对海洋核电平台,提出一种疲劳评估方法。考虑海洋核电平台的工作特性,工作状态时选取首向浪向不等概率分布的波浪载荷,拖航状态时选取全浪向等概率分布的波浪载荷,分别计算出两种波浪载荷下的疲劳损伤度,再根据两种状态下的时间分配系数得到总的损伤度。根据提出的疲劳评估方法,建立核电平台的有限元模型,选取危险疲劳节点进行细化处理,通过有限元分析得到应力传递函数以及疲劳损伤度,验证了评估方法的可靠性,确定了危险疲劳节点的位置,并为类似平台的疲劳问题提供参考。     

491QE汽油机涡轮增压系统设计及模拟计算

为了提高491QE汽油机的性能,进行了增压系统的开发工作。通过计算确定了增压参数,并在原发动机基础上设计了定压排气管和脉冲转换排气管两种增压系统。利用循环模拟程序计算了491QE汽油机增压以后的性能。结果表明,脉冲转换系统在发动机废气能量的利用方面优于定压系统。     

基于数字信号处理器实现特定消谐脉宽调制控制技术的研究

在大功率交流传动控制中,传统的PWM(脉宽调制)方法输出由于存在低次谐波,会使电流和转矩产生脉动,影响控制精度.以三相电压型逆变器为分析对象,提出了一种基于数字信号处理器(DSP)来实现特定次谐波消除脉宽调制(SHEPWM)控制技术.该技术是首先根据SHEPWM控制技术的基本原理建立其特定谐波消除中开关角与调制度之间的...     

核安全级膨胀节的应用和设计制造特点

核电站核岛用膨胀节具有要求高、责任重大的特点。文中以压水堆核电站为例,对核岛管道中膨胀节的应用、设计、制造特点及产品设计、制造过程中应控制的关键点等进行了阐述,以供借鉴。     

铜镍管直流脉冲TIG焊工艺试验与应用

为改善铜镍管焊接时的焊缝成形、提高焊接质量,选择手工直流脉冲钨极惰性气体(Tungsten Inert Gas,TIG)焊并采取无间隙组对进行工艺试验。经相关检测,焊后内外焊缝成形优良,表面无缺陷,X射线探伤满足规范要求。试验结果表明:采用手工直流脉冲TIG焊可有效改善管子内壁焊缝成形、减少焊接缺陷、提升焊接质量;采取无装配间隙的组对方式可提高管子零件的制作精度与工作效率,在实船应用中得到推广并取得较好的效果。     

A line impedance stabilization network for pulse current injection北大核心CSCD

［Objective］Aiming at the deficiency of the existing line impedance stability network (LISN) in the electromagnetic pulse protection capability, a LISN suitable for the pulse current injection (PCI) test of electrical and electronic equipment is proposed. ［Methods］Aiming at the characteristics of high peak value and fast rise of the pulse current in PCI testing, the circuit structure and physical structure of the LISN are improved on the existing basis through PSpice time-domain and frequency-domain simulation combined with engineering design requirements, thereby giving it good nanosecond pulse protection performance and impedance stability at the same time. Pulse current protection performance test and impedance curve test experiments are then designed and carried out.［Results］The experimental results show that the improved LISN can attenuate the injected pulse current by 60 times, while the error of its impedance curve is less than 5% compared with the Type 5 µH LISN in GJB 151B-2013. ［Conclusions］The proposed LISN has good impedance stability and decoupling ability, and can be used in the PCI testing of electrical and electronic equipment in order to protect the power supply and improve the repeatability of testing. © 2023 Chinese Journal of Ship Research. All rights reserved.     

Numerical method of electromagnetic pulse response of conductor with complex load北大核心CSCD

[Objectives]Electromagnetic pulse can seriously affect and even destroy naval shipborne electronic information systems, weapons, equipment and so on. Due to the complexity of the antenna port load circuit, it is necessary to formulate a numerical method which can easily obtain the antenna load current. [Methods]The induced current of the terminal is obtained on the basis of the finite-difference time-domain (FDTD) and Holland model. According to the Thévenin equivalent circuit, the conductor is equivalent to the voltage source to realize decoupling between the conductor and load end, and the load circuit is solved using Simulink software.[Results]Compared with the traditional terminal model, this method is simple and feasible for high-order circuit processing. The effectiveness of the model is verified using non-linear elements and parallel capacitors and resistors as the load respectively. The results show that the calculation results of this method are consistent with those of the traditional methods. Finally, the antenna of the end-connected protect- or is calculated. The results show that the lead inductance caused by the installation of the protector is an important factor affecting the protection performance.[Conclusions]The method proposed in this paper can greatly reduce the simulation complexity of the coupling current of an antenna with a complex load, giving it useful reference value for the field of ship electromagnetic pulse protection design. © 2023 Editorial Department of Chinese Journal of Ship Research. All Rights Reserved.