【作者】 柳春宝；

【导师】 李笑；

【作者基本信息】 广东工业大学 ， 机械电子工程， 2012， 硕士

【摘要】 神经源性膀胱是指由于人体控制排尿的中枢神经受到损害而引起的膀胱排尿功能障碍。该病可引发膀胱结石、泌尿系统感染、肾功能衰竭等并发症,给病人带来极大的痛苦,对其治疗或辅助病人排尿是医学界公认的难题。目前,对神经源性膀胱治疗尚无有效办法。针对此问题,本课题提出了一种体外电磁驱动的膀胱动力泵。通过体外电磁铁产生的电磁场对体内磁动子产生电磁驱动力,调节尿道口和输尿管口开闭,压迫膀胱排尿。模拟实验证明该泵工作原理可行,但开启尿道口所需的电磁驱动力较大,导致电磁铁结构较大。为了优化膀胱动力泵的结构,有必要对其尿液配流机构做出改进。为此,本文设计了一种新型的膀胱动力泵尿道阀。运用电磁学理论和流体力学理论,建立了尿道阀的数学模型,利用该模型仿真分析了电流和气隙等不同因素对尿道阀特性的影响。通过仿真和实验对比,验证了所建立模型的有效性。在模拟实验台上,研究了尿道阀对膀胱动力泵排尿动力特性的影响规律。结果表明：增大电磁铁电流、减小电磁铁与尿道阀之间的气隙,有利于提高最大尿流率、缩短尿流时间。尿道阀是膀胱动力泵实现尿液配流的重要部件,一旦发生失效,将导致泵失去辅助排尿作用。因此,研究提高尿道阀的可靠性具有重要的意义。为了提高尿道阀的工作可靠性,根据尿道阀的结构原理及故障树,建立了尿道阀可靠性仿真模型。基于蒙特卡罗方法基本思想,提出了尿道阀可靠性仿真算法,并仿真计算了尿道阀的可靠度、失效概率、底事件重要度和模式重要度等指标。仿真与实验结果表明：尿道阀寿命达到50000次的可靠度为0.73；弹性带脱落和老化是尿道阀的薄弱环节。研究结果可为膀胱动力泵特性分析和结构优化设计提供依据,为设计新型的辅助排尿装置提供指导,对合理设计适用于人体的生物医学装置有参考作用。更多还原

【Abstract】 Neurogenic bladder is a term applied to a malfunctioning urinary bladder, which is caused by the injured central nervous that controls urination. Some complications can be caused by the disease, such as bladder stone, urinary system infection, renal failure and so on. It can bring great pain to patients, and the treatment of the disease or assisting micturition has been generally acknowledged as difficult problem by medical researches. There is no effective way to the neurogenic bladder at present. In order to solve the problem, a bladder power pump driven by an external electromagnet was proposed. An external electromagnet produces electromagnetic force which acts on a magnetic mover, and the tension of magnetic mover makes the orifices of ureters and urethra close and open. As a result, the urine of urinary bladder is continuously discharged by the press of magnetic mover. The feasibility of the working principle of the pump was proved by simulated experiment. But, a great electromagnetic force for opening the orifice of urethra and a big electromagnet were required. To optimize the structure of the pump, the distribution mechanism of the pump should be improved.Therefore, a new urethra valve of the bladder power pump was designed in this paper. The mathematical model of the urethra valve was built based on the theories of electromagnetics and hydromechanics. The model was used to analyze the characteristics of the urethra valve effected by different electromagnet current, air gap and so on. The validity of the model was confirmed through the comparison between simulation and experiment. The effects of the urethra valve on the micturition performance of the pump were studied on simulated experiment system. The results show that increasing electromagnet current and decreasing air gap between the electromagnet and the urethra valve are beneficial to increasing maximal urine flow rate and decreasing urine flow time.The urethra valve is a major part of the pump for realizing flow distribution of urine. Once the urethra valve is in fault, the pump will lose the function of assisting micturition. So, it is important to study the reliability of the urethra valve. In order to improve the reliability of the urethra valve, a simulation model of the reliability of the urethra valve was built based on the structure principle and fault tree of the urethra valve. According to the principle of the Monte Carlo method, a simulation algorithm of the reliability of the urethra valve was proposed. Some reliability indexes of the urethra valve were calculated, such as reliability, failure probability, importance of bottom events, mode importance and so on. The simulation and experiment results showed that the reliability of the urethra valve is0.73when the life is50000times; both shedding and aging of elastic band are the weaknesses of the urethra valve.The conclusion can provide the basis for performance analysis and structural optimization design of the bladder power pump, and provide the guidance for the design of new device for assisting the bladder micturating, as well as the guidance for the design of biomedicine device.更多还原