【作者】 张国伟；

【导师】 何雪浤；

【作者基本信息】 东北大学 ， 机械设计及理论， 2015， 硕士

【摘要】 通风隔离阀主要应用于核电站空调通风系统,开启时正常通风调节室内温度,关闭时阀板压紧密封圈保证放射性气体泄漏量要求,并具有一定的自锁功能,在发生事故时能起到对系统的自动隔离作用。其传动系统传递的运动是否精确决定了阀板关闭密封性能和自锁性能的好坏。为评估和提高通风隔离阀传动系统的运动可靠性,确定科学合理的设计加工和维护方案,本文主要考虑到传动系统的原始加工误差和运动副的使用磨损误差对运动可靠性的影响,提出了一种较为全面的可靠性分析评估方法,对其运动可靠性及其可靠度的灵敏性进行分析计算。首先考虑加工尺寸原始误差的变化,在分析传动系统的结构功能特点以及受载情况的基础上,基于应力-强度干涉模型建立传动系统阀板关闭可靠度和自锁可靠度的计算模型。根据密封要求,利用ADAMS动态仿真模拟实验的方法,确定在传动系统所传递的转角下阀板关闭密封功能和自锁功能可靠的判据即两者允许输出误差极限的分布情况;基于蒙特卡罗原理,利用ADAMS编程自动仿真的方法,模拟机构真实尺寸误差和铰链副配合间隙的随机变化,统计得出其输出误差的分布情况,计算可靠度。其次考虑传动机构运动副磨损使运动副间隙变化产生的误差,基于应力-强度干涉模型建立铰链副磨损可靠度计算模型,并分别确定许用极限磨损量的分布情况和实际磨损量的分布情况,计算铰链副磨损可靠度。确定实际磨损量的分布情况时,基于Archard磨损计算模型,推导建立了适合本研究的磨损量计算模型,通过ADAMS动态仿真较为精确地分段拟合获得运动副受力和角速度变化规律,同时假设铰链副间隙误差为一随机变量,最后基于蒙特卡罗原理较为精确地模拟获得其分布情况。进一步地,论文综合考虑了原始误差和磨损误差,将磨损量与原始输入误差叠加,再次进行多次仿真实验,对传动系统的运动输出进行可靠性分析计算,求解阀板关闭可靠度和自锁可靠度。最后,基于响应面法对通风隔离阀传动系统重要参数进行可靠性灵敏度分析计算。选取实验方法获取实验样本点,通过Design-Expert软件拟合得到极限状态函数,进一步获得可靠度功能函数,对各随机变量求解导数信息,可计算得到可靠性灵敏度。结果表明,各参数对阀板关闭可靠性的灵敏度高于对自锁可靠性的灵敏度,设计加工方案时,在公差等级内,应适当降低各参数的方差,并根据灵敏度变化趋势控制参数加工误差均值的高低,后期检测维护中,应特别重视可靠性灵敏度较大的参数的变化。依据分析计算结果,提出了科学合理的设计加工和维护建议。本文为研究通风隔离阀传动系统的运动可靠性问题提供了一种较为全面的分析评估方法,为企业提供技术支持。更多还原

【Abstract】 Ventilation isolation valves are mainly used in air conditioning and ventilation systems of nuclear power plants.They are required to ensure proper ventilation and cooling function when they are open,and compacting seal with a self-locking function to meet leakage requirements when closed,futher in the event of an accident,they can play an important role in automatic isolation function for the system.Accuracy of motion transmited by ventilation isolation valve transmission system is key to sealing and self-locking performance of the valve.The purpose of this study is to evaluate and improve motion reliability of a type of ventilation isolation valve’s transmission system,then to determine its reasonable precision plan of machining,assembly and maintenance.A comprehensive reliability assessment calculation method is proposed in this paper considering original errors in process of machining and assembly and errors due to wear and tear of hinge pairs during working process.Apply this method to conduct calculation analysis of transmission system’s motion reliability as well as its sensitivity,which have a great significance on improving its reliability.Firstly,motion reliability analysis was conducted considering original errors.This study analyzed its structure characteristics and force condition,then built a valve plate closing reliability and self-locking reliability calculation model based on stress-strength interference model,established ADAMS models of valve plate and transmission mechanism to conduct simulations for many times,and futher determined the distribution of allowable limit output error considering the valve’s seal and self-locking function requirements.Programed ADAMS language automatic simulation program to simulate and obtain output results data corresponding to a large number of input parameter values,futher abtained output error’s distributions of valve plates closing angles and self-locking angles based on MonteCarlo theory,calculated and got reliability results according to calculation model built formerly.Secondly,wear reliability analysis of the transmission system’s hinge pairs was conducted.A hinge pair’s wear reliability calculation model was built based on the stress-strength interference model.Then distributions of allowable amount of wear and distributions of actual allowable amount of wear in work were determined,then the wear reliability was calculated.In the calculation process,the amount of wear formula was deduced based on the improved Archard wear model,and the hinge force and angular velocity functions were derived by ADAMS dynamic simulation and precisely fitting method,what’s more,this study took sizes of hinge shafts and holes as random variables,simulated and got the distribution of the wear valve based on MonteCarlo theory,it’s more accurate and closer to actual work condition.Furthermore,added the calculated amount of wear to the original errors,then conducted motion reliability analysis considering both original errors and hinge pairs’ wear.Valve plate closing reliability and self-locking reliability were calculated.Finally,sensitivity analysis of reliability was conducted considering the transmission system’s important parameters based on response surface method.First chose experimental method to get experimental sample points and then fitted limit state function by Design-Expert software,and further obtained the reliability performance function,then sensitivity of reliability was calculated through solving its derivative information for each random variable.The results shows that the parameters for sensitivity of the valve plate closing reliability is higher than sensitivity of the self-locking reliability.During the design process,the variance of each parameter should be reduced,,the mean value should be controled according to the trend of the sensitivity within the tolerance level.In the later detection and maintenance process,the parameters with higher reliability sensitivity should be paid more attention to.Scientific and rational processing,assembly and maintenance recommendations were proposed according to the calculation results.In conclusion,a comprehensive motion reliability calculation assessment method for ventilation isolation valve’s transmission system is proposed in this paper,which will provide technical support for enterprise.更多还原