一起钢质无缝气瓶爆炸事故技术分析

简述一起气瓶爆炸事故发生后的现场情况,对爆炸气瓶进行了宏观检查、壁厚测定、化学成分分析、金相组织分析、硬度测定和力学性能试验,分析后得出爆炸的原因是腐蚀引起壁厚减薄造成强度不足,并提出了预防类似事故的措施。     

浅析铝合金无缝气瓶的硬度试验

通过对铝合金无缝气瓶材料性能和热处理机理的分析,解释了铝合金无缝气瓶材料硬度下降的原因,说明了硬度试验在铝合金无缝气瓶制造和定期检验过程中的重要作用。     

70 MPa储氢气瓶快速充氢温度效应的影响因素分析

车载储氢容器在快速充气过程中会产生显著的温度效应,对复合材料气瓶基体强度、疲劳性能以及有效供氢量具有很大的影响.以氢气为介质,从理论和试验两方面进行了70 Mpa储氢气瓶快速充气的温度效应影响因素研究,以控制充气温度不超过85℃的气瓶工作温度上限.通过简化的理论模型分析得出了充气温度效应的决定因素和影响因素,分析结果在...     

锅炉炉管爆破原因分析

对在爆裂的水冷壁管正常管段和鼓包处所取的试样分别进行化学分析、金相检验、硬度测定和高温拉伸试验。分析结果表明，在近烧嘴的炉管长期处于超温工作状态，引起该部位材质严重劣化，高温强度不断下降，当该部位的高温强度低于锅炉炉管对材质所要求的技术条件即会发生爆裂。对炉管的继续使用提出了应急的预防措施。     

车用缠绕气瓶声发射检测初步研究

针对车用缠绕气瓶的缠绕层材料复杂、不能直接有效地进行检测等问题,对其中的玻璃纤维缠绕层气瓶进行声发射分析、研究,找出合适的传感器布置方案和定位方式。通过大量研究,在声发射信号众多参数中发现费利西蒂比是评价缠绕气瓶的重要参数,它能反映气瓶损伤以及爆破强度,在随后对气瓶破坏试验过程中验证了研究结论的正确性。     

7060铝合金热处理工艺对气瓶疲劳性能的影响

热处理工艺的选择决定了气瓶的材料性能及使用性能。7060铝合金强度很高,应用于铝合金无缝气瓶表现为疲劳性能较差。经过工艺筛选,可以制定一种既满足气瓶疲劳性能要求且强度较高的热处理工艺,以满足生产需要。经过疲劳试验结果对比,通过过时效工艺将铝瓶的强度控制在极限强度的80%可以满足气瓶的疲劳性能要求,且三级过时效工艺优于双级过时效工艺。     

气瓶安全与检验问答(二十六)

问:气瓶整体或局部被火烧过,怎样对其进行检验评定?答:气瓶整体或局部被火烧的情况,大致可分为4种:(1)漆膜烧焦或烧毁;(2 )金属烧结;(3)气瓶变形;(4 )瓶阀件熔化。在受检瓶上发现上述(2 )、(3)情况时,应把受检瓶评定为报废。如果受检瓶的漆膜仅被烧焦或鼓包而未脱落,则说明未伤及金属,应评定为合格。在受检瓶漆膜被烧脱落或瓶阀件被烧熔化的情况下,如果条件不允许把被烧的受检瓶送气瓶制造厂按原工艺重新进行热处理和试验,则该瓶应评定为报废。在气瓶定期检验中,还会遇到另外两种局部热损伤:(1)在气瓶上进行电焊引弧导致瓶体出现“弧疤”;(2…     

锅炉锅筒鼓包原因分析及预防

采用化学分析及金相检验等方法 ,对锅炉锅筒产生的鼓包原因进行了分析。结果表明 ,锅炉严重结垢使得锅筒底部钢板长期过热产生蠕变 ,从而导致锅炉锅筒产生鼓包变形     

35 Cr3 NiMoA 钢件的热处理工艺改进

为满足产品热处理后头部具有足够的强度,心部与整个截面均淬透,整个截面布氏硬度印痕直径按梯度分布,头部布氏硬度印痕直径达到2.9 ～3.1 mm,尾部布氏硬度印痕直径达到3.3～3.6mm的工艺要求,最终采用局部感应回火热处理.在靶场强度试验时,产品头部出现断裂现象,分析原因是局部感应回火热处理后,温度梯度产生内应力所致.为解决此问题,热处理后增加一次全弹回火,消除了由于温度梯度而产生的应力.工艺改进后,经小批量生产考核,产品质量稳定,通过了靶场穿透强度试验,保证了产品性能,并利于切削加工.     

301奥氏体不锈钢薄板拉伸强度与冷轧硬度之间的关系

为对冷轧不锈钢薄板的产品硬度控制提供指导,尝试用一个新的方法来取代试轧,既达到控制冷轧板硬度的目的,又能降低成本、提高效率。对0.99mm厚的经过退火的301奥氏体不锈钢薄板进行冷轧减薄,并进行室温拉伸试验,测量其维氏硬度。通过观察金相和利用X射线衍射,验证了应变诱导马氏体相变是导致301奥氏体不锈钢冷轧和拉伸时产生加工硬化的主要原因。试验结果表明,冷轧和拉伸有着相似的加工硬化趋势,综合拉伸与轧制试验数据,确定了拉伸强度与冷轧硬度之间的关系,实现了通过拉伸强度来得到对应应变下的冷轧硬度,具有很好的预见性。冷轧可以提高301不锈钢的强度和硬度,显著改善其力学性能。     

Measurement of residual stresses in thick composite cylinders by the radial-cut-cylinder-bending method

Thick fabric composite cylinders for nozzle parts in solid rocket motors should be designed to endure the extreme temperature and pressure of combustion gas. As the thickness of the composite cylinder increases, fabricational residual stresses due to the anisotropic thermal expansion or shrinkage of fabric composites also increase, which induces inter-laminar failures. Therefore, the accurate estimation of the residual stresses is indispensable for the development of thick fabric composite cylinders.

In this paper, the residual stresses in thick cylinders made of carbon fabric phenolic composites were measured by a new radial-cut-cylinder-bending method. To obtain the residual stresses from the measured relative strains during the radial-cut operation, a bending test of the cylinder with the radial-cut was performed instead of measuring the material properties with respect to radial positions. The thermal residual stresses were also calculated by finite element method considering shear deformation of fabric layers, and compared with the measured residual stresses by the new method, from which it was found that the new simple method estimated the residual stresses pretty well. Also the inter-laminar tensile strength at the position of maximum radial residual stress could be obtained from the bending test.     

聚酰亚胺纤维与碳纤维缠绕复合气瓶性能对比研究

本文主要研究高性能国产聚酰亚胺纤维在复合材料气瓶上的应用,并表征其与进口碳纤维的性能差距.采用国产聚酰亚胺纤维进行缠绕成型工艺优化与复合材料性能测试分析,在测试数据及工艺优化基础上针对其进行了复合材料气瓶的强度设计.分别采用聚酰亚胺纤维、进口T300、T700以及T800碳纤维缠绕成型复合材料气瓶,进行水压爆破压强的测试,并引进声发射检测技术对其在水压过程中的损伤信号进行监测分析.结果表明聚酰亚胺纤维缠绕工艺性良好,与树脂界面结合优异,适用于湿法缠绕成型工艺.复合材料拉伸强度达到1 708 MPa,纤维的强度发挥率高达80%,相比于碳纤维复合材料其呈现出较好的断裂韧性,有利于减少复合材料气瓶在水压下的应力损伤.缠绕成型的聚酰亚胺纤维复合材料气瓶容器特征系数(PV/W)高达32.2 km,其在航空航天、医用、汽车、核工业等领域具有广阔的应用前景.     

Behavior of normal and high-strength concrete cylinders confined with E-glass/epoxy composite laminates

This paper is aimed at studying the behavior of concrete cylinders with varying compressive strength wrapped with E-glass/epoxy fiber reinforced polymer (GFRP) jackets and subjected to uniaxial compressive loads. A comprehensive experimental program which involves 54 plain concrete cylinders was conducted in this study. The cylinders evaluated in this study, were divided into six groups, and each group contain a control cylinder without confinement to quantify the amount of gain obtained using the GFRP laminates. Experimental results indicated that the use of GFRP jackets substantially increases both the compressive strength and ductility of unreinforced concrete cylinders. In this paper, the influences of two parameters influencing the behavior of the GFRP confined cylinder is investigated. These parameters are: the number of composite plies (i.e. composite thickness) and concrete compressive strength. The results of this study showed that: (i) compressive strength and ductility of the concrete cylinders increases with number of composite layers; and (ii) effect of confinement is substantial for normal strength concrete and marginal for high-strength concrete. A semi-empirical theoretical model is also presented in order to predict stress–strain relationship of GFRP confined concrete cylinders. The model results showed an excellent agreement with experimental values.     

玄武岩纤维布增强树脂基复合材料约束高温损伤混凝土轴压力学性能

对36个玄武岩纤维布增强树脂基复合材料（BFRP）约束加固的高温损伤混凝土圆柱体和15个不同高温损伤的对比试件进行了轴压试验。试验表明,BFRP侧向约束能显著改变混凝土圆柱体的破坏形态,提高混凝土圆柱体的轴压强度和变形能力。其中二层BFRP包裹的200℃、400℃、600℃和800℃高温损伤混凝土圆柱体的轴压强度分别提高了56%、82%、234%和250%,轴向变形分别提高了328%、198%、232%和136%。采用典型的纤维增强复合材料约束常温未损伤混凝土轴压强度和变形计算模型预测纤维增强复合材料约束高温损伤混凝土轴压极限强度和极限变形时存在较大的偏差。基于本文试验数据,确定了BFRP约束高温损伤混凝土极限应力和极限应变计算模型中与温度相关的参量,建议了适用于预测纤维增强复合材料约束高温损伤混凝土的极限应力计算模型和极限应变计算模型。     

充填聚氨酯泡沫的薄壁金属筒的力学性能研究

通过充填聚氨酯泡沫的薄壁金属圆筒的力学性能试验,研究薄壁金属圆筒内充填聚氨酯泡沫的作用和效果。试验比较了空心薄壁金属圆筒和充填聚氨酯的薄壁金属圆筒的轴向抗压荷载一位移曲线和破坏模式．试验结果表明充填聚氨酯后可大大改善薄壁金属筒的力学性能,提高其抗变形和吸收能量的能力．     

基于模型试验和数值模拟的柔性串列圆柱体涡激振动研究

采用物理模型试验和CFD数值模拟方法研究了大长径比、低质量比的柔性串列圆柱体涡激振动现象。通过分析串列圆柱振幅、振动频率、受力特性和流场结构等特性,着重研究流速和圆柱间距对下游圆柱涡激振动特性影响。研究发现,上、下游圆柱涡激振动幅值差别较大,并且当流速大于某个值后,两者主导频率也不相同,由此提出分离约化速度U r。流速和间距都会影响上游尾流对下游圆柱的作用,其中流速会影响上游尾涡强度及其发展程度,间距会影响上游尾涡发展空间及其与下游圆柱的接触位置。     

端部状态对斜拉索节段模型气动特性的影响

为了给实际工程中串列三圆柱结构的风荷载取值提供参考,通过刚性模型测压风洞试验方法,测试了12个不同间距比L/D(L为两圆柱中心之间的距离,D为圆柱的直径)下串列三圆柱的平均风压系数和平均阻力系数,并与单圆柱的平均风压系数和平均阻力系数进行了对比。研究结果表明：串列三圆柱存在临界间距,其临界间距比为3.0≤L/D≤3.5。三个圆柱的平均阻力均小于单圆柱的平均阻力;上游圆柱的平均阻力最大,下游圆柱的平均阻力次之,中游圆柱的平均阻力最小。     

A comparison of liquid hydrocarbon calibration standards in piston cylinders and standard cylinders with eductor tubes

Natural gas liquid standards consist of various components primarily in the C1-C6 range; they are available in three types of cylinder packages: piston cylinders and two other types of standard cylinders with eductor tubes. The three cylinder packages have different operation conditions and thus a sample may behave differently in each of the packages. The piston cylinder maintains the components in a single liquid phase at a constant pressure, while the standard cylinders maintain the components as a two-phase mixture. Typically, the components may distribute between the two phases in different concentrations depending on the various thermodynamic variables, such as temperature, pressure, and volume. This study will examine the integrity of the sample in the three cylinder packages during a controlled cylinder depletion. The results for the various cylinders will be compared with a theoretical model of the experiments.     

Structural integrity assurance of high-strength steel gas cylinders using fracture mechanics

This paper describes fracture mechanics criteria employed in the development of fracture-safe, 155–175 ksi strength level steel cylinders. A new steel composition was developed to obtain the toughness required to satisfy leak-before-break and plastic fracture mode criteria. Cylinders were fabricated from the new steel, and tests were conducted to characterize their flaw tolerance capability. Leak-before-break and plastic fracture mode performance was verified. Flawed cylinder tests were also conducted on conventional 3AA 4130X steel cylinders (105–125 ksi strength level) to characterize their flaw tolerance capability. The flaw tolerance capability of the high-strength cylinders was found to be equal to that of the conventional low strength steel cylinders at respective service stresses.