Experimental and numerical study of hypervelocity impact damage on composite overwrapped pressure vessels

Ground-based tests are important for studying hypervelocity impact(HVI)damage to spacecraft pressure vessels in the orbital debris environment.We analyzed the damage to composite overwrapped pressure vessels(COPVs)in the HVI tests and classified the damage into non-catastrophic damage and catastrophic damage.We proposed a numerical simulation method to further study non-catastrophic damage and revealed the characteristics and mechanisms of non-catastrophic damage affected by impact conditions and internal pressures.The fragments of the catastrophically damaged COPVs were collected after the tests.The crack distribution and propagation process of the catastrophic ruptures of the COPVs were analyzed.Our findings contribute to understanding the damage characteristics and mechanisms of COPVs by HVIs.

Exploration on the Optimization Strategy for the Layup of Composite Material Pressure Vessels Based on Advanced Algorithms

This study aims to explore the influence of the laying angle on the pressure shell structure made of composite materials under the condition of a fixed shape. By using a composite material composed of a mixture of T800 carbon fiber and AG80 epoxy resin to design pressure vessels, this material combination can significantly improve the interlaminar shear strength and heat resistance. The article elaborates on the basic concepts and failure criteria of composite materials, such as the maximum stress criterion, the maximum strain criterion, the Tsai-Hill criterion, etc. With the help of the APDL parametric modeling language, the arc-shaped, parabolic, elliptical, and fitting curve-shaped pressure vessel models are accurately constructed, and the material property settings and mesh division are completed. Subsequently, APDL is used for static analysis, and the genetic algorithm toolbox built into Matlab is combined to carry out optimization calculations to determine the optimal laying angle. The research results show that the equivalent stress corresponding to the optimal laying angle of the arc-shaped pressure vessel is 5.3685e+08 Pa, the elliptical one is 5.1969e+08 Pa, the parabolic one is 5.8692e+08 Pa, and the fitting curve-shaped one is 5.36862e+08 Pa. Among them, the stress distribution of the fitting curve-shaped pressure vessel is relatively more uniform, with a deformation of 0.568E−03 m, a minimum equivalent stress value of 0.261E+09 Pa, a maximum equivalent stress value of 0.537E+09 Pa, and a ratio of 0.48, which conforms to the equivalent stress criterion. In addition, the fitting curve of this model can adapt to various models and has higher practical value. However, the stress distribution of the elliptical and parabolic pressure vessels is uneven, and their applicability is poor. In the future, further exploration can be conducted on the application of the fitting curve model in composite materials to optimize the design of pressure vessels. This study provides important theoretical support and practical guidance for the design of composite material pressure vessels.

Non-destructive Evaluation of Composite Pressure Vessel by Using FBG Sensors

In recent years, advanced composite structures are used extensively in many industries such as aerospace, aircraft, automobile, pipeline and civil engineering. Reliability and safety are crucial requirements posed by them to the advanced composite structures be- cause of their harsh working conditions. Therefore, as a very important measure, structural health monitoring （SHM） in-service is deft- nitely demanded for ensuring their safe working in-situ. In this paper, fiber Bragg grating （FBG） sensors are surface-mounted on the hoop and in the axial directions of a FRP pressure vessel to monitor the strain status during its pressurization. The experimental results show that the FBG sensors could be used to monitor the strain development and determine the ultimate failure strain of the composite pressure vessel.

The Analysis of the Line Pattern of Nonlinear Winding Filament on FRP Composite Air Vessel Resisting High Pressure

The FW process is a prefect method of manufacturing FRP composite air vessel resisting high pressure and aerial press vessel.In this paper FW pattern of FRP composite air vessel resisting high pressure was analyzed in a nutshell.The stability of FW patterns on end head is very sensitive to changing of pattern parameter.Consequently,its FW pattern was based on geodesic track.The FW angles and on equators depend on the dimension of end part and the condition of geodesic FW.Generally speaking, the polar holes of rocket engine shell are disproportional.Therefore,the FW angles of the shell column are changeable.The feasi- bility of nongeodesic FW of the shell column was discussed in this paper.Furthermore,it expounded the indispensable condition be- tween the length of shell column and the FW friction coefficient.At the same time,the general mathematic models of the movement control of nongeodesic FW were deduced.

Finite Element Analysis of Graphite/Epoxy Composite Pressure Vessel

Shell structure is widely used in industrial applications, such as in machinery, aerospace, ship and building fields, as well as containers of pressurized chemicals or liquefied natural gas. Graphite/epoxy composites has advantages of light weight, high strength, corrosion resistance, low expansion, low shrin kage and are often used in the form of composite pressure vessel for various engineering applications. In this study, the stress distributions of composite pressure vessel were analyzed. The finite element code ANSYS was used in analysis, in which the eight-node element SHELL 281 was adopted. The internal pressure 20 MPa, as in container of compressed natural gas, was applied inside the symmetrical cross-ply graphite/epoxy composite pressure vessel. The finite element model was established with suitable mesh size and boundary conditions. The stress distributions are discussed for the composite pressure vessel, especially for the inner two layers at the junction of semis pherical part. The Tsai-Hill criterion was used to assess the failure of composite pressure vessel.

S31603复合板压力容器点蚀行为试验研究

针对S31603复合板压力容器不锈钢层不同点蚀深度的发展进程及穿透至碳钢层后的电偶腐蚀风险,通过预制不同点蚀深度的S31603复合板试片组,分别在实验室和现场S31603复合板压力容器内进行腐蚀试验,并对试片进行宏观分析、低倍观察、高倍观察及腐蚀产物表征分析。结果表明,S31603复合板预制的点蚀坑深度穿透至碳钢层时发生了明显的电偶腐蚀,实验室腐蚀试验和现场试验最高点蚀速率分别达到4.954,1.023 mm/a;用S31603复合板试片预制的点蚀坑深度穿透至碳钢层后碳钢优先发生电偶腐蚀;S31603复合板试片预制的点蚀坑深度处于不锈钢层时腐蚀轻微,也未萌生新的点蚀,相邻点蚀坑之间也未见明显的腐蚀影响。在含Cl-的酸性腐蚀性介质环境下,当S31603复合板压力容器点蚀深度处于不锈钢层时腐蚀轻微,当点蚀深度穿透至碳钢层后,会发生明显的电偶腐蚀,需要缩短S31603复合板压力容器开罐检修周期以保证安全使用。

高低温对碳纤维/环氧树脂复合材料高压气瓶的性能影响

为了获得T1000碳纤维/环氧树脂复合材料高压气瓶环境适应能力,有效地掌握气瓶高低温适应性固有规律,以容积50 L、工作压力30 MPa的复合材料气瓶(钛为内衬、碳纤维/环氧树脂为复合层)为研究对象,首先介绍了高低温循环下带压气瓶(在-40~80℃范围内成功通过热真空、热循环验证,具备高压承载能力)的热真空、热循环试验数据,然后采用与气瓶相同复合材料的拉伸试样(缠绕角分别为0°和90°),通过高低温极限摸底试验获得了复合材料经历不同梯度高低温后的拉伸性能数据,通过数据比对分析获得了高低温影响拉伸强度衰减的规律。同时,提出了一种高低温极限摸底试验的可靠性评估方法。结果表明,在-50~100℃范围内,试样拉伸强度及断裂伸长率变化较小;当温度高于100℃时,纤维和树脂的性能发生衰减,导致拉伸强度明显降低;当温度低于-50℃时,树脂的性能发生衰减,纤维受到的影响较小。试样高低温极限摸底试验的可靠度大于0.999,表明采用拉伸试样高低温拉伸强度数据的替代方式具有较高的等效性。

油田用纤维增强塑料压力容器的应用及研究进展

纤维增强塑料压力容器具有耐腐蚀性好、比强度高、耐疲劳性好、质量轻、易于成型、保温性好等优点,近年来逐渐应用于油气处理领域。首先,对纤维增强塑料压力容器在国内油田的应用现状和成型工艺进行了介绍;其次,对影响纤维增强塑料压力容器性能的因素进行了分析总结;然后,对纤维增强塑料压力容器的相关标准进行了介绍,并对国内外纤维增强塑料压力容器无损检测技术的相关研究进行了综述;最后,对纤维增强塑料压力容器在油田的发展趋势进行了展望。

大壁厚不锈钢复合板压力容器建造关键技术及应用

在大壁厚不锈钢复合板压力容器的建造过程中,通过深入研究其技术要点和难点,优化焊接接头结构设计,成功形成了一套完整的新型建造关键技术。这套技术不仅优化了焊接接头结构,还创新了一系列施工方法,包括筒体加热卷制、接头坡口机加工、接管内壁耐蚀层TIG/FCAW自动堆焊、不锈钢衬管液氮冷套、球形封头内壁耐蚀层带极埋弧堆焊、纵环缝窄间隙埋弧自动焊以及管口接头马鞍型埋弧焊等。这些新型建造关键技术的应用,在提高压力容器质量效果的同时,也带来了显著的经济效益,为行业同类型设备的建造提供借鉴。在未来的研究中,可以进一步探索这些技术在其他领域的应用,以实现更广泛的技术交流和合作。同时,对于大壁厚不锈钢复合板压力容器的建造,仍需不断深入研究其材料特性、工艺参数和施工方法,以不断提高设备的性能和安全性。

Fatigue test of carbon epoxy composite high pressure hydrogen storage vessel under hydrogen environment

A significant temperature raise within hydrogen vehicle cylinder during the fast filling process will be observed, while the strength and fatigue life of the cylinder will dramatically decrease at high temperature. In order to evaluate the strength and fatigue of composite hydrogen storage vessel, a 70-MPa fatigue test system using hydrogen medium was set up. Experimental study on the fatigue of composite hydrogen storage vessels under real hydrogen environment was performed. The experimental results show that the ultimate strength and fatigue life both decreased obviously compared with the values under hydraulic fatigue test. Furthermore, fatigue property, failure behavior, and safe hydrogen charging/discharging working mode of onboard hydrogen storage vessels were obtained through the fatigue tests.

Mechanical analysis and reasonable design for Ti-Al alloy liner wound with carbon fiber resin composite high pressure vessel

To consider the internal pressure loaded by both the cylindrical Ti-Al alloy liner and the carbon fiber resin composite (CFRC) wound layers, two models are built. The first one is a cylinder loaded with the internal pressure in the hoop direction only. In this model, the total hoop direction load is distributed over all layers under the internal pressure. The second one is a cylinder loaded with the internal pressure in the axial direction only. In this model, the total axial load is distributed over all cylinders under the internal pressure. Taking the boundary conditions of the continuous displacement between layers into account, a group of equations are built. From these equations, we get the solutions of stresses in both hoop direction and axial direction loaded by every layer under internal pressures. After the stresses are obtained, a reasonable design can be done. An example is given in the final section of this study.

APPLICATION OF SURROGATE BASED PARTICLE SWARM OPTIMIZATION TO THE RELIABILITY-BASED ROBUST DESIGN OF COMPOSITE PRESSURE VESSELS

A surrogate based particle swarm optimization （SBPSO） algorithm which combines the surrogate modeling technique and particle swarm optimization is applied to the reliability- based robust design （RBRD） of composite pressure vessels. The algorithm and efficiency of SBPSO are displayed through numerical examples. A model for filament-wound composite pressure vessels with metallic liner is then studied by netting analysis and its responses are analyzed by using Finite element method （performed by software ANSYS）. An optimization problem for maximizing the performance factor is formulated by choosing the winding orientation of the helical plies in the cylindrical portion, the thickness of metal liner and the drop off region size as the design variables. Strength constraints for composite layers and the metal liner are constructed by using Tsai-Wu failure criterion and Mises failure criterion respectively. Numerical examples show that the method proposed can effectively solve the RBRD problem, and the optimal results of the proposed model can satisfy certain reliability requirement and have the robustness to the fluctuation of design variables.

Theoretical study of failure in composite pressure vessels subjected to low-velocity impact and internal pressure

A theoretical solution is aimed to be developed in this research for predicting the failure in internally pressurized composite pressure vessels exposed to low-velocity impact.Both in-plane and out-of-plane failure modes are taken into account simultaneously and thus all components of the stress and strain fields are derived.For this purpose,layer-wise theory is employed in a composite cylinder under internal pressure and low-velocity impact.Obtained stress/strain components are fed into appropriate failure criteria for investigating the occurrence of failure.In case of experiencing any in-plane failure mode,the evolution of damage is modeled using progressive damage modeling in the context of continuum damage mechanics.Namely,mechanical properties of failed ply are degraded and stress analysis is performed on the updated status of the model.In the event of delamination occurrence,the solution is terminated.The obtained results are validated with available experimental observations in open literature.It is observed that the sequence of in-plane failure and delamination varies by increasing the impact energy.

考虑张力制度影响的碳纤维缠绕容器爆破性能预测与仿真插件开发

针对缠绕张力对碳纤维缠绕容器承载性能影响规律尚不明确的问题,基于ABAQUSTM软件开发了一套用户友好、自主选择性好且高效的插件工具,能够自动化完成模型建立和相关设置工作,实现了考虑多种缠绕工艺参数的容器结构精细化建模。基于该插件工具,对碳纤维缠绕容器在不同缠绕张力制度下的爆破性能进行了参数化分析,通过爆破试验验证了数值模型的有效性。对于直径为Ф155 mm和Ф474 mm的容器,90 N-80 N-60 N和200 N-180 N-160 N逐层减小的缠绕张力制度将提高容器的爆破性能;对于20 N和30 N递减张力制度,直径Ф474 mm容器的爆破压强随着内层张力的减小逐渐降低,当张力递减幅度增加时,容器的爆破压强趋于稳定,其下降幅度由16.79%减小到3.05%。此外,容器封头段与筒身段过渡区域的应变水平最高,为碳纤维缠绕容器的薄弱位置。

螺栓连接压力容器耐压强度性能

针对较小长径比复合材料压力容器需进一步减重的应用需求,设计了一种螺栓连接大开口复合材料压力容器,并以直径290 mm压力容器为例,基于网络分析法,设计了碳纤维复合材料压力容器的纤维铺层厚度、缠绕角度以及层数等信息。利用水压试验首先考察了直径6.5 mm、材质分别为TC4和TC11的螺栓对大开口碳纤维复合材料压力容器耐压强度的影响;在此基础上考察了直径9 mm、材质分别为TC4,TC11和35CrMnSi的螺栓对压力容器耐压强度的影响。试验结果表明,螺栓连接复合材料压力容器承载内压时,螺栓连接部位的复合材料为薄弱区域,该部位复合材料需满足挤压、轴向拉伸以及环向承载,因此需额外补强。同时,螺栓需具备足够的抗拉、抗弯强度,相同材质下,随着螺栓直径的增大,受力面积增加,其抗拉、抗弯强度大幅提高;通过选用更高强度的螺栓,复合材料压力容器的耐压强度大幅提高。

超薄单层复合材料缠绕压力容器承载性能研究

针对压力容器承载性能,基于经典层合板刚度等效理论,提出了一种可以考虑复合材料缠绕层单层厚度的压力容器承载性能分析方法;与实际铺层有限元模型进行对比,验证了分析方法的有效性;对不同单层厚度的复合材料进行了单向拉伸试验,获得材料强度与单层厚度的关系;分析了超薄单层复合材料缠绕压力容器的应力分布、失效系数分布及失效压力。结果表明,超薄单层复合材料缠绕压力容器的应力和损伤分布更为均匀,失效内压较常规单层厚度复合材料可提高54.5%。该研究成果可为超薄单层复合材料缠绕压力容器的结构设计提供可靠的理论参考。

某气田复合板压力容器腐蚀原因分析

为了确定复合板(Q345R+316L)压力容器的腐蚀原因并制定应对措施,对复合板腐蚀部位进行了宏观形貌分析和理化检验,并采用循环极化法和恒电位法对复合板复层不锈钢在氯离子环境下的耐点蚀性能和钝化能力进行验证。结果表明:复合板在氯化物环境下存在明显的点蚀倾向,且无法进行再钝化,不满足当前环境下的服役工况,需要对压力容器采取一定应对措施来控制氯离子腐蚀的发生。

复合材料压力容器的概率和非概率可靠性设计

考虑复合材料压力容器结构中各参数和载荷的随机性或区间性,利用基于概率的网格法得到其纤维强度发挥系数随机函数的计算表达式。建立了该类压力容器的可靠性分析模型,并分别应用随机因子法和区间因子法导出了纤维强度的均值、标准差和离差的计算表达式,利用概率的和非概率的可靠度计算方法,实现了该类压力容器的概率和非概率的可靠性设计,并考察了结构各不确定性参数的波动对容器厚度设计尺寸的影响。算例结果表明:概率和非概率的可靠性设计结果均可满足安全要求,且比传统的安全系数法结果更为精确与合理;概率方法相比非概率方法,其结果相对误差较小,但计算过程较为复杂。

球形压力容器的裂纹应力强度因子分析

为探究双材料球形压力容器裂纹初始角度对于裂纹应力强度因子的影响,以N6-Q345双材料球形压力容器作为研究对象,通过建立有限元模型进行数值模拟的方式模拟N容器不同的裂纹初始角度,并结合相互积分作用法对应力强度因子进行计算。结果表明:裂纹Ⅰ型、Ⅱ型应力强度因子会随着裂纹初始角度增大而增大,但Ⅱ型应力强度因子会在裂纹初始角度为45°时达到最大值,超过45°则会降低;高强度性能Q345材料侧的裂纹尖端应力强度因子要始终高于低强度性能N6材料侧的裂纹尖端应力强度因子;J积分、等效应力强度因子会随着初始角度的增大而增大,但Ⅰ型应力强度因子占据主导地位,裂纹更易向着高强度材料(Q345)界面侧发生扩展。

关于锆-钢复合板制压力容器的风险探讨

锆在大多数有机酸、无机酸、强碱和某些熔融盐中都有优良的耐腐蚀性能,锆复合板制压力容器是近些年广泛应用于过氧化氢、醋酸、硝酸、尿素等化工行业的重要化工设备。因锆材不能与铁基材料熔焊,其材料要求、结构设计、制造检测方面都比较特殊。本文结合笔者实际设计经验,从该类容器关键点的工程应用风险角度,探讨影响其安全性的材料应用、关键结构设计制造检测两方面的风险点及其风险控制。经过详细的阐释对比、应用论证,择选出具有最佳工程应用优势的主焊缝焊接结构及其检漏结构。