气压复位型电梯缓冲器的缓冲性能优化

电梯用油压缓冲器一般采用弹簧或柱塞复位，本文探讨了一种气压复位型的电梯用油压缓冲器，通过建立冲击过程的动力学方程，并应用正交优化方法和MATLAB动态仿真对其缓冲性能进行优化，寻找出关键参数——节流孔布局的近优解。     

电梯用油压缓冲器的动态仿真和试验分析

考虑缓冲器柱塞头部橡胶垫的刚度和阻尼的作用，将柱塞和轿厢分别作为质量块，建立电梯用油压缓冲器的数学模型并对其进行动态仿真，同时以一实际的油压缓冲器为例，通过试验，证明了所建数学模型正确性并为油压缓冲器的设计提供依据。     

一起囊式蓄能器爆炸事故分析

针对一起囊式蓄能器爆炸事故,通过化学成分分析、力学性能测试、金相检验、宏观分析、扫描电镜断口分析以及爆炸压力计算等方法对该起事故的原因进行了分析。结果表明:该囊式蓄能器的爆破压力远远高于其设计压力,其爆炸性质为化学爆炸;主要是由于在皮囊补气过程中误将氧气装入,使蓄能器内部发生燃烧,从而导致了该次爆炸事故。     

高速缓冲器机理探究

通过对小质量高速缓冲器的模型的建立，对在这类缓冲器在缓冲的过程中的各种缓冲参数选择和计算进行相应的分析和讨论，为高速缓冲提出了建设性的建议。     

混合介质缓冲器的动力学特性及缓冲效果研究

介绍一种新型的混合介质缓冲器,其中的混合介质由不可压缩的航空机油与可压缩的空心橡胶小球组成。当冲击发生时,液体将动压力瞬间传递到所有小球上,使它们同时参与变形,冲击能量可被大幅度吸收、损耗。若设计得当,这类缓冲器可具有卓越的缓冲性能。建立了混合介质缓冲器的动力学方程,利用MatLab得到该方程的数值解,并通过试验验证了动力学模型的准确性。理论分析了不同冲击作用下该系统的位移功率谱及混合介质缓冲器的各参数对缓冲效果的影响,对混合介质缓冲器的缓冲效果作出评价。     

潜孔钻机油气缓冲系统动态特性研究

为减小潜孔钻机冲击振动对动力头疲劳损坏,设计一套安装于动力头与钻杆之间的压力可调式油气缓冲系统,对该油气缓冲系统结构进行分析,阐述其工作原理。根据蓄能器工作原理,构建蓄能器等效模型。基于潜孔钻机和油气缓冲系统工作特性,建立带有该油气缓冲系统潜孔钻机振动模型。运用Matlab软件进行系统仿真,得到蓄能器充气体积、蓄能器预充压力、阻尼孔直径对系统动态特性综合影响规律。通过实验验证了模型的正确性,可为油气缓冲系统设计与优化提供理论参考。     

简支曲梁结构的大变形及吸能分析

目的 通过对简支曲梁缓冲器的非线性大变形及能量吸收特性的理论研究,为其缓冲设计与应用提供理论参考。方法 基于Euler–Bernoulli梁理论,以曲梁的曲率半径及截面角为基本参数推导简支圆形曲梁大变形控制方程,考虑压板作用下曲梁的多种变形情况给出曲梁的大变形及变形能的解析表达,进而计算不同外力及初始安装角下缓冲器的变形情况及变形能,并与数值计算结果进行对比。结果 理论计算结果与数值解高度吻合,表明计算方法的可靠性,缓冲器的缓冲系数取决于曲梁材料、初始曲率半径及安装角度,与其数量无关;当初始安装角为 时,缓冲器的最小缓冲系数可取到6.12。结论 所讨论曲梁缓冲器具有明显的非线性大变形特性和良好的缓冲吸能特性,能够替代传统缓冲材料,方便地用于运输系统的缓冲设计中,给出了简支曲梁缓冲器的基本设计方法。     

正切型弹性体材料的缓冲包装设计

提出一种利用正切型弹性体材料的力学数据进行缓冲包装结构设计的方法,对这种方法的原理进行详细的理论推导,得出计算缓冲垫结构尺寸的关系式。该关系式简单实用,设计出的缓冲衬垫具有最佳的理论缓冲效率。     

三次函数型弹性体材料的缓冲包装设计

介绍采用以弹性体材料的力学数据进行缓冲包装设计的方法，对三次函数型弹性体材料的缓冲包装设计进行了详细的理论推导，得出计算缓冲垫结构尺寸的关系式。     

安装差动胶泥缓冲器的舰炮检验弹入膛仿真分析

舰炮检验弹由于结构不同于实弹,入膛时反弹速度过大,造成相关零部件断裂和关闩故障。故设计采用差动胶泥缓冲器吸收过大的动能以保证检验弹的入膛可靠性。为评估差动胶泥缓冲器在检验弹上的缓冲效能,以及分析检验弹的入膛运动规律,提出一种结合缓冲器流体数值分析(computational fluid dynamics,CFD)和入膛多体动力学分析(multi-body dynamic,MBD)的仿真分析方法。计算结果表明:此方法能够准确计算和预测缓冲器的缓冲效能,检验弹的缓冲器满足设计技术要求;静压过程在活塞后方形成多个涡旋,而冲击过程流线平稳无涡旋;黏性阻抗分力随压缩速率降低先增大后减小。研究不仅为胶泥缓冲器在舰炮检验弹上的应用提供理论支撑,还为胶泥缓冲器本身的研究提供新的分析方法。     

摆杆式操作机钳杆平升降缓冲刚度与阻尼研究

针对摆杆式锻造操作机钳杆吊挂系统的液压缸与蓄能器组合缓冲装置,以平升降运动为例,提出基于动力学理论分析获得缓冲刚度与阻尼的思路,据设备结构形式简化吊挂系统的物理模型,利用拉格朗日法分析平升降运动的动能及势能,建立吊挂系统平升降动力学模型。以50 kN操作机为例,在Matlab中求解动力学方程,获得缓冲装置刚度及阻尼对吊杆摆动角、工件质心位置、钳杆摆角的变化规律,分析刚度及阻尼对平升降运动的影响,提出确定缓冲装置刚度及阻尼的方法,为摆杆式锻造操作机缓冲装置油缸与蓄能器设计提供理论依据。     

Modeling and experimental investigation of accumulators for automotive air conditioning systems

A stream analysis model was developed to simulate the behavior of accumulators and their influence on the automotive air conditioning (A/C) systems. It allows a comprehensive steady state simulation with a set of input conditions such as refrigerant vapor mass flow rate and pressure at the inlet of an accumulator. In this study, the refrigerant/oil mixture is R134a/PAG oil which are totally miscible, but could be any air conditioning refrigerant/oil, including carbon dioxide (CO₂)/oil. The model accounts for all major effects inside the accumulator, such as friction, bends, sudden expansion, sudden contraction and heat exchange. The outputs are vapor quality, pressure and temperature at various positions of accumulator. In order to verify the mathematical model, experiments are performed in an experimental setup made up of real size automotive air conditioning components. The simulated results agree well with the experimental data. The simulation and experimental results show an important function of accumulators that is to determine the vapor quality into compressor, and thus has influence on the performance of whole automotive A/C systems.     

直线型涡流缓冲装置的设计

 针对高速运动体缓冲制动的特点设计了一种直线型涡流缓冲装置．该装置利用涡流产生的阻尼力,对高速运动体进行非粘着制动．[JP2]推导了缓冲力的理论计算公式,将理论计算结果同有限元计算结果进行对比,验证了理论公式的可用性．在缓冲装置中,采用Halbach阵列代替常规永磁体阵列,并对缓冲效果进行对比计算,表明采用Halbach阵列的涡流缓冲装置缓冲性能更优．该装置可有效避免常规缓冲制动过程中发生的物体接触、碰撞和磨损．     

增塑剂对以天然植物纤维类为填料的发泡缓冲材料性能的影响

研究了在不同增塑剂用量的情况下,试验样品的密度、动态缓冲曲线和静态缓冲曲线.通过对增塑剂用量与试验样品密度、动态缓冲系数及静态缓冲系数的关系的分析,得出了增塑剂对缓冲材料影响的规律.选择了最佳的增塑剂用量.     

活塞式蓄能器爆炸原因分析

某活塞式蓄能器在使用过程中发生爆炸,通过对收集到的蓄能器碎片进行断口及表面宏观分析、材料化学成分和力学性能分析、扫描电镜分析、物相分析和能谱分析,并应用有限元应力分析软件进行理论爆破压力计算,找出了蓄能器爆炸的原因。结果表明:爆炸系该活塞式蓄能器内所充入气体中含有氧气,当一定浓度的氧气与渗入气体侧的液压油混合后,在机械运转过程中的激发能源的作用下发生剧烈的燃烧化学反应,瞬间产生高温高压而导致蓄能器发生爆炸。     

房间空调器制冷系统贮液器的设置

本文讨论了房间空调器制冷系统中需要设置贮液器的依据,以及选择和设置贮液器所涉及的安全性、可靠性、技术性以及经济性等问题.     

Isoelectric buffers for capillary electrophoresis. 2. Bismorpholine derivative of a carboxylic acid as a low molecular weight isoelectric buffer

A new compound class of synthetic isoelectric buffers is introduced, designed as a small molecule with one fully or prevailingly dissociated acidic group (such as sulfonic or carboxylic) and two partly pronated (buffering) basic amino groups attached onto a hydrophilic UV-transparent backbone. As an example, a new isoelectric compound 2,2-bis(4-morpholinylmethyl)propanoic acid (BMMPA) was synthesized by attaching two morpholine groups onto a molecule of pivalic acid. It was characterized as having an isoelectric point pI = 6.5 and exhibiting satisfactory buffering capacity at the pI. Solutions of BMMPA are transparent down to the low-UV spectral region, thus making it a potentially suitable buffer for a number of separation methods. Its use in capillary electrophoresis was demonstrated in a separation system for indirect photometric detection of anions based on an electrolyte with the anionic dye Orange G as the indirect detection probe and using BMMPA as a buffer. The use of an isoelectric buffering compound brings the advantages of a buffered electrolyte without the concomitant introduction of co-ions that would be detrimental to the indirect detection process. Submicromole per liter limits of detection for a number of inorganic and small organic ions were achieved. Optimal structural properties of the isoelectric buffer with respect to its buffering properties are discussed.     

Practical methods for measuring refrigerant mass distribution inside refrigeration system

The purpose of this paper is to present methods for measuring refrigerant mass distribution inside a refrigeration system conveniently and accurately. The quasi on-line measurement method (QOMM) was presented for measuring refrigerant mass inside heat exchangers. Compared with the existing liquid nitrogen method (LNM), QOMM can avoid the refrigerant waste and accelerate the measurement process. For measuring refrigerant mass inside the compressor, QOMM was used together with the oil level observation method. The liquid level method (LLM) was used to measure the refrigerant mass inside the accumulator and the receiver. In order to verify the accuracy of the measurement methods, not only the deviation of the measurement method for refrigerant in single component was analyzed, but also the prediction of the total refrigerant charge in an air conditioner was verified. The results showed that the maximal prediction deviation of the refrigerant charge in the whole refrigeration system is 1.7%.