平衡式弧形体挠性接管的缠绕模型研究

为了保证挠性接管在使用过程中的安全性,需要对其进行平衡性设计。提出一种新型弧形体挠性接管的设计方法。采用直管内部加压、两端向内挤压的方法进行弧形体挠性接管成型,通过对纤维帘线进行建模,确定直管对应于不同帘线缠绕角的长度;采用有限元方法计算确定满足平衡性要求的直管帘线缠绕角。通过合理设计以保证弧形体挠性接管具有足够的平衡性。     

JYXR系列舰用挠性接管研究

JYXR系列舰用挠性接管主要包括JYXR(L)型肘形挠性接管、JYXR(P)型平衡式挠性接管和引俄JYXR型挠性接管3个系列.研究打破了欧、美、俄等发达国家的技术封锁,突破了肘形管的平衡性设计原理、软管骨架材料芳纶纤维的实用化技术、可靠性设计、帘线在弯曲非对称体上精确、均匀缠绕技术、三法兰一体化接头设计等重大理论、技术难题,成功研制出符合研制技术要求的高性能JYXR系列挠性接管产品,为舰艇管路系统减振抗冲设计提供了有力的技术支撑.     

挠性接管安装工艺对系统振动传递影响试验研究

为了解挠性接管安装工艺状态对机械隔振系统振动传递特性的影响,选取某型船舶上典型的管路系统及挠性接管为研究对象,采用二分法进行了挠性接管不同安装工艺偏差对系统振动传递特性影响的试验研究。结果表明,在一定安装工艺偏差范围内,船体结构振级、马脚下部振级、挠性接管远设备端振级变化不大,在安装过程中应控制挠性接管工艺参数在规定偏差范围内。     

挠性接管布置对管路系统振动特性的影响分析

在实际管路系统低噪声安装施工中,由于受船舶安装空间因素的限制,振源附近通常没有位置安装挠性接管,此时往往会改变挠性接管的安装位置。由于挠性接管安装位置改变,管路系统振动特性也随之改变。针对以上问题,建立安装有挠性接管管路系统的有限元模型,改变挠性接管安装位置,计算指定点在单点激励下的振动特性,最后进行实验验证。结果表明:尽管理论上挠性接管的布置应尽量靠近振源,但在实际安装过程中,若安装空间不允许,可根据空间位置适当调整挠性接管与振源的相对位置,实验证明合理地调整其安装位置对管路系统振动噪声控制影响较小。这一研究将为管路系统挠性接管的低噪声安装提供实践参考和理论依据。     

弧形管疲劳寿命预测研究

弧形管是一种常用的管路连接件,在服役时长期受到大位移疲劳载荷的作用。传统工程实践中针对挠性接管处于疲劳载荷在可靠性检验多采用抽样试验方法,该方法存在试验成本高,置信度差的缺点,且未从失效机理上对弧形管疲劳失效进行有效分析。本文将汽车行业橡胶件疲劳寿命预测常用的裂纹萌生法应用于弧形管。通过单轴疲劳拉伸试验,建立基于各种疲劳损伤参数的寿命预测模型,结合弧形管三维实体有限元仿真模型和寿命预测模型,对拉压工况下的疲劳寿命进行预测并通过加速试验进行了验证。该论文研究结果可用于指导弧形管疲劳可靠性设计。     

金属挠性接管变形监测的研究

本文在分析金属挠性接管变形的基础上，提出了金属挠性接管测点布置及测点所满足的数学模型，由此数学模型能监测金属挠性接管的变形情况。     

JYXR型挠性接管减振性能试验研究

对JYXR型挠性接管进行了不同泵压状态下的管路系统减振性能的试验,试验结果表明,JYXR型挠性接管具有很好的减振性能,对船舶的可靠性和改善船员的工作与生活环境有重要的意义.     

挠性接管对管壁弯曲振动的隔离性能分析

采用分析软件ANSYS就理想情况下袖套式挠性接管在不同的边界条件和布置情况下，对管路中沿管壁传播的弯曲振动的隔离性能分析表明，挠性接管在大部分频段上能有效的隔离弯曲振动，但也有可能使振动放大，这与其边界条件和布置情况密切相关，由此对挠性接管的布置安装提出建议.     

大口径大位移挠性接管研究

本课题完成了三球型薄壁橡胶挠性接管结构及其优化设计,模型与样品研制,确定系列化型谱,模型与样品的性能与强度试验,样品装机隔振性能试验等。经专家们评审一致认为,三球体橡胶接管各向位移补偿性能优异,装机试验隔振效果良好,在技术上有创新。对挠性接管进行了在额定压力下的轴向压缩与剪节刚度试验,提供了力变形曲线。这在国内尚属首次,为浮筏技术发展做出了贡献。     

基于管体变形实时监测的挠性接管寿命评估方法

针对凯夫拉纤维增强型挠性接管(FW-FP)管体发生局部异常变形而导致管体破裂失效的问题,提出一种基于管体变形实时监测的挠性接管寿命评估方法。融合电阻感应原理和光纤光栅(FBG)传感原理,在建立管体结构模型的基础上,采用数值计算和有限元仿真方法,对管体轴向变形、径向变形、充压变形及局部异常变形特性进行分析,提取出区分管体正常变形和局部异常变形的特征阈值。该方法能够有效识别管体的局部异常变形,实时评估挠性接管的工作寿命。     

Analysis of Numerical Results in High Temperature Congealment and Chemistry Non-equilibrium Flow Field

Using the air plasma ignition technique, physicochemical process of burning can be accelerated; concentration limit ofretrofires both can be extended; reliability of retrofires and stability of burning can be improved. In this paper, using internalequivalent heat area in place of electric are that created Ohm heat, the flow fields of thermodynamic equilibrium chemistry con-gealment and chemistry non-equilibrium in the plasma generator were simulated. The influences of the inlet prerotation angleof air, the inlet total pressure of air and the airflow compression angle of spray nozzle on the temperature on the surface of elec-     

A finite element model for unbonded flexible pipe under combined axisymmetric and bending loads

Flexible pipes are key equipment for offshore oil and gas production systems, conveying fluids between the platform and subsea wells. The structural arrangement of unbonded flexible pipes is quite complex, encompassing several layers with polymeric, metallic and textile materials. Different topologies and a large amount of intricate nonlinear contact interactions between and within their components, especially because of the relative stick-slip mechanism during bending, makes numerical analysis challenging. This paper presents an alternative three-dimensional nonlinear finite element model that describes the response of flexible pipes subjected to combined axisymmetric and bending loads. To simulate the response of a flexible pipe under axial tension or compression combined with uniform curvature, an equivalent thermal loading is employed on the external sheath, which is modelled as an orthotropic thermal expansion material with temperature-independent mechanical properties. To assess the feasibility of the proposed model, the bending moment versus curvature of the finite element solution is compared with experimental results obtained in literature and good agreements are found between them. Detailed finite element results such as contact pressures, armour wire slip displacements and friction, normal and transverse bending stresses are also shown and compared with available analytical models.     

钢带软管内压和弯曲研究

复合材料管已成为管道发展的热点和趋势。文中对钢带软管在同时受到内压和弯曲组合载荷作用下的力学性能进行了研究。基于建立的钢带软管的环向和径向力学平衡方程,提出了不同弯曲半径下该种类型管道的爆破压力理论计算方法。文中还进行了有限元数值模拟,并与理论计算结果对比分析,分析结果表明文中提出的爆破压力计算方法可作为此类管在同时受到内压及弯曲组合载荷作用下的通用算法,为解决此类工程问题提供重要参考。     

Local structural analysis of flexible pipes subjected to traction,torsion and pressure loads

Helically armored cables or pipes find a wide range of applications as structural members in engineering. An example of this is the increasing use of flexible pipes in the oil offshore production. Although keeping a geometrical similarity with other helically armored structures such as wire ropes and ACSR conductors, and borrowing from them a useful methodology for the structural analysis, some care must be taken in order not to indiscriminately use an approach which was not thought for a flexible pipe: internal and external pressures, for instance, are a great concern in the analysis of flexible pipes, but obviously not for wire ropes. This work aims at giving some additional contribution to the structural response of flexible pipes when subjected to axisymmetric loads, including the effect of both internal and external pressure in pipe displacements. Derivation of linear operators, relating the stress-resultants to their related displacements or deformations in each of the layers of the pipe, as well as the process of deriving an analogous linear operator to represent the behavior of the pipe as a whole, are clearly presented, highlighting interesting mathematical aspects and their associated physical meaning. A numerical case study of a 2.5″ flexible pipe subjected to traction and internal pressure is also presented and discussed.     

气囊隔振器囊壁骨架层平衡性研究

气囊隔振器囊壁帘线层满足平衡性时的理论缠绕角度的取值随囊体波纹角变化而变化,导致其帘线铺设时工艺复杂。针对该问题,文中提出取值恒定的帘线最优等效平衡缠绕角的概念,并推导出其计算公式。结合算例理论分析,有限元仿真分析和试验研究,验证了帘线最优等效平衡缠绕角概念的存在性和正确性。研究成果可为气囊隔振器的设计生产提供理论依据和指导。     

A finite element methodology for birdcaging analysis of flexible pipes with damaged outer layers

Flexible pipes are commonly exposed to damages on the outer layers due to abrasion with seafloor or improper installation and operation, which may render them vulnerable to birdcaging failures. This paper presents a finite element model for the residual axial compressive strength evaluation of a flexible pipe with local damage on the outer layers. The elastoplastic nonlinearity of tensile armour steel layers and hyperelasticity of polymeric outer sheath are taken into account. This model is verified against existing test data. Parametric studies are then performed by varying the damage size in either the pipe axial or circumferential directions. The flexible pipe axial resistance, deformations, as well as the tensile armour wires layers stress states near the damaged section under different damage and axial compression conditions are discussed. The case studies show that damage on the outer layer, especially the anti-birdcage tape layer, is highly detrimental to flexible pipe residual strength against axial compression. The present results and discussions are instructive in understanding the flexible pipe birdcaging mechanism.     

Mechanical behavior of metallic strip flexible pipes during reeling operation

Metallic strip flexible pipes (MSFP), a relatively new style of unbonded flexible pipes, are considered as an attractive alternative to traditional submarine pipes. During its reeling operation, it will inevitably confront various complicated loads, which may affect the integrity and safety of MSFP's utilization. In this paper, the tension-extension and moment-curvature relation of MSFP were obtained by laboratorial tests. The mechanical properties were then imported into the global model established in ABAQUS. The finite element model was adopted to predict the deformation and mechanical responses of MSFP during the operation process. Besides, the effects of reeling length, the diameter of the coiling drum, and the pulling force were discussed. The obtained conclusions will provide some references for optimizing MSFP design and preventing possible damage in the reeling operation.     

Axisymmetric structural behaviours of composite tensile armoured flexible pipes

To address the weight and corrosion challenge in deep-water, replacing the steel tensile armour in flexible pipes with composite materials is an alternative conceptual approach. An axisymmetric structural responses model is built for this novel composite armoured flexible pipe, with interlayer gaps that may occur in the unbonded structure considered through an iterative algorithm. The tensile strength of steel and composite armoured pipes are predicted based on different constitutive relations of steel and composite. Essential quantities are obtained, such as tensile stiffness, deformations of each layer and interlayer gaps or contact pressures. Considering the helix form of carcass and pressure armour, a finite element model is established for the verification of the theoretical model. Case study shows that the tensile stiffness of flexible pipe is overestimated with the interlayer gap ignored. Compared with steel armoured flexible pipe, the composite armoured pipe, whose tensile stiffness decreases less as external pressure increases, meanwhile has higher values of tensile ultimate strength and torsion stiffness. Some suggestions about fiber types and volume fraction for composite tensile strips are given to ensure good performance of axial tensile strength and stiffness.