Here, to study fluid-structure coupled characteristics of braided composite liquid-filled pipeline, a 1D fluid-structure coupled dynamic model of composite pipeline was established using the transfer matrix method based on anisotropic material constitution equation, physical equation and boundary conditions. The model was degenerated into isotropic pipeline to verify calculation method, and the fluid-structure interaction verification of composite pipeline FEM software was further performed. The calculation results showed that the calculation results using the proposed method are consistent to those of the classical “4 equation” model and the finite element 3D model. After proving the correctness of the proposed model and calculation method, effects of laying angle and fiber volume fraction in composite pipeline on natural frequencies and wave number of liquid-filled pipeline were further studied. The results showed that natural frequencies of pipeline increase and its propagation wave number decreases with increase in volume fraction of reinforcement material; as laying angle increases, natural frequencies decrease, and propagation wave number in pipe wall increases; the study results can provide a reference for design and control of liquid-filled pipeline.

Abstract Two kinds of periodic composite pipes with support or dynamic vibration absorber are designed based on the theory of phononic crystals. Axial vibration and band gaps of composite fluid-filled pipe are calculated by using transfer matrix method and Bloch wave theory. The present fluid–structure interaction model and frequency domain calculation method are validated by comparing the velocity of fluid from a FEM model. The results show that the stop bands frequency of velocity responses are in good agreement with band gap. Longer length of a single cell decreases the beginning frequency and width of both two kinds’ band gaps.

The nonlinear, in-plane mechanics of a thin-walled honeycomb with zero Poisson's ratio under large deformation is investigated in this paper. A theoretical method for calculating in-plane tensile modulus, modified factors of linear constitutive relations of the honeycomb structures with zero Poisson's ratio is proposed based on the theory of Euler-Bernoulli beam and the bending theory of beam in large deflection, and a finite element simulation is given to validate. In addition, parametric analysis for revealing the impacts of geometrical configurations and material parameters on in-plane mechanical properties of the honeycombs have been studied systematically. These findings suggest that geometric and/or material parameters provide different contributions to the effective mechanical properties and lead to a separate design for the in-plane mechanical properties. After that, the effects of geometric and/or material nonlinearities on mechanical properties of the honeycomb structures with zero Poisson's ratio are revealed by considering the dimensionless tangent stiffness of the honeycombs.

In this paper, torsional vibration band gap properties of a fluid filled pipe were studied by using the transfer matrix method (TMM). By comparing the results obtained from the fem software, the established torsional dynamic model and the proposed method were verified. The effects of pipe wall's material and parameters of support on the torsional vibration band gap properties were analyzed. Furthermore, the relationship between torsional displacement and vibration band gaps was investigated. These attenuation regions of responses show good agreement with the frequency of Bragg band gaps. Explained the locally resonant (LR) phononic crystals (PCs) band gaps form mechanism from the point of mechanical impedance mismatch theory, the results show that the peak frequency of impedance mismatch defines the beginning of both LRs and Bragg band gaps. In essence, the locally resonant is the same as periodic support from the impedance theory. The results of this paper could give some valuable suggestions on the vibration control of the pipeline system.

This paper studies the vibration band gap characteristics of a liquid-filled composite pipeline. The transfer matrix method is used to create a one-dimensional fluid–structure interaction model of the composite pipeline from the constitutive equation, physical equations, and boundary conditions of the anisotropic material. A phononic crystal pipeline is designed with a periodic arrangement on the axial pipe wall. The method used to analyze the fluid–structure interaction of liquid-filled composite and phononic crystal pipelines is verified by comparing responses with finite-element method results. The results’ agreement demonstrates the method’s and calculation code’s correctness. Furthermore, the band gaps for an empty composite phononic crystal pipe, water hammer, and a liquid-filled pipe are calculated by Bloch vector theory, and the effects of fluid–structure interaction and the composite parameters on the three band gap characteristics are analyzed. The numerical results show that Poisson’s coupling affects the band gap at some frequency points, while the laying angle and fiber volume fraction in the composite pipe influence the band gap length and amplitude change. The research results of this paper provide a reference for the design and vibration control of liquid-filled composite pipelines.

为抑制充液管路中轴向振动波传播,利用吸振器安装点处位移与轴向力连续条件,采用传递矩阵法建立充液管路带多个吸振器动力学耦合模型,与有限元计算结果对比,验证了该计算方法的正确性.计算分析了轴向波在吸振器前后的透射与反射系数,并进一步计算了吸振器周期排列时管路轴向振动带隙.研究结果表明:轴向波在吸振器共振频率全部反射,反射系数带宽随吸振器刚度与阻尼增大而变化;吸振器周期分布时,管路系统轴向振动同时存在局域共振型带隙与Bragg带隙,轴向波在局域共振型带隙内得到了有效的抑制.研究结果可为管路轴向减振、吸振器设计提供参考.

管路-内含铺板圆柱壳耦合结构是潜艇、鱼雷等水下航行器装备中的典型结构,为研究管路与圆柱壳结构耦合振动噪声传递的特性,论文采用阻抗综合法,利用耦合点处力与位移连续条件,建立管路-支撑-圆柱壳耦合结构振动计算模型.管路采用考虑流固耦合以及剪切变形的"十四方程"理论,从振动功率流传播视角研究管路系统向内含铺板圆柱壳振动传递的特性,并用边界元软件计算耦合结构远场辐射声功率.计算结果表明:充液管路各簇振动功率流分布与幅值随频率、管路支撑位置而变化,且管路系统输入功率流与耦合系统远场辐射声功率相关.研究结果可为管路系统从能量流角度进行振动控制提供参考.

本文基于管内平面波假设,考虑泊松耦合,从基本方程出发,推导充液柔性接管的声阻抗、机械阻抗和机械-声、声-机械耦合阻抗的解析表达式,通过算例对轴向阻抗结果以及耦合与非耦合的阻抗结果进行对比,研究几何参数对轴向阻抗结果的影响,比较钢管和橡胶管的轴向阻抗值.所给出的计算公式拓展和完善了现有柔性接管阻抗的理论研究工作,可以为耦合阻抗试验测试提供理论依据.研究结果对于柔性接管动态特性的综合研究、提高管路系统声学设计水平具有重要的意义.

Dynamic vibration absorbers (DVAs) are often used to reduce vibrations in narrow frequency ranges. To reduce the flexural vibrations of a fluid-filled pipe system in a broader frequency band, several DVAs are attached to the pipe periodically to constitute a system akin to a locally resonant phononic crystal. Each DVA is analyzed based on mechanical impedance theory, and Bloch wave theory and the transfer matrix method are used to investigate the wave propagation in such a periodic system. The validity and accuracy of the natural frequencies and dynamic responses obtained are verified by comparing the present numerical results with results from the finite-element method. Also analyzed are the band-gap formation mechanism and how various system parameters influence the band-gap behavior, such as how the lattice and absorber properties influence the location and width of the lowest band gap. Lastly, a mass–spring DVA is designed and attached periodically to find the existence of locally resonant band gaps. The analytical and experimental results show that the mechanical impedance of the DVA is the main factor for the band-gap formation mechanism. When the DVAs are periodically arrayed, it can more effectively control flexural pipe vibration by broadening the bandwidth they attenuate and increase the magnitude of vibration attenuation.

基于考虑剪切变形与转动惯量的Timoshenko梁理论,建立充液U型管流固耦合动力学模型.采用传递矩阵法求解U型管路固有频率与简谐激励下的稳态响应,并通过与FEM计算结果对比,验证了本文计算方法的正确性.采用该计算方法对管内流体的质量效应与弯曲半径对传递函数的影响进行了计算分析.本文提出的U型管路流固耦合计算方法可为换热器中U型管的减振降噪设计提供参考.