船舶管路系统中金属软管动力学性能的有限元法研究

在ANSYS中建立了金属软管的动力学有限元模型,本文对金属软管的振动模态进行了仿真分析,并将分析结果与试验进行了对比,证明了动态有限元模型的可靠性,对金属软管的谐响应和瞬态振动响应进行了有限元仿真分析,分析结果对金属软管的设计、安装和使用具有非常重要的实用价值。     

基于ANSYS的金属软管的动态有限元分析

运用非线性有限元法,采用三维壳单元Shell93和空间梁单元Beam18,利用耦合和约束理论,在ANSYS中建立金属软管的有限元模型,对金属软管进行动态有限元分析(包括模态分析和瞬态分析),得到金属软管的任意阶固有频率,振型以及位移-时间曲线,并将分析结果与试验结果进行比较,证明了有限元建模及其分析结果的正确性,为金属软管的力学性能和设计分析尤其在防止共振方面的研究提供了参考.     

基于子结构技术的金属软管静力学性能分析

利用子结构技术,在ANSYS中建立了金属软管的三维有限元模型。利用此模型对金属软管在轴向拉伸、轴向压缩、横向错动、弯曲和多种载荷联合作用等工况下的静力学性能进行了分析,并将分析结果与试验结果进行对比,证明了有限元建模的可靠性。     

金属软管失稳分析及结构优化

金属软管在横向位移和内压作用下发生失稳后,承载能力大幅下降,影响管路系统的安全运行。本文对某DN300金属软管进行了失效分析,确定了其失效模式和失效原因,并有针对性的对相关结构参数调整后进行建模计算,最终获得不同几何参数金属软管在横向位移和内压作用下失稳载荷随几何参数的变化规律。结合曲线的变化趋势,优化该类金属软管的局部结构,为今后其设计和制造提供了理论支撑。     

基于ANSYS的金属软管的瞬态动力学分析

运用非线性有限元法,采用三维壳单元Shell93和空间梁单元Beam189,利用耦合和约束理论,在ANSYS中建立金属软管的有限元模型,对金属软管进行瞬态动力学有限元分析,得到金属软管在一个周期内的阻尼迴滞曲线以及动态响应,并将计算结果与试验结果进行比较,证明了有限元建模及其计算结果的正确性,为金属软管的力学性能和动态设计分析以及将来的寿命分析的研究提供了参考.     

金属软管的静态有限元分析

对金属软管的拉伸、压缩、错动等特性分别进行有限元分析,得到了波纹管和网套的特性曲线,并且将分析结果与试验结果进行比较,证明了有限元建模的合理性,为金属软管的动态特性分析建立了可靠的有限元模型.     

基于ANSYS的金属软管的静态有限元分析

运用非线性有限元法，波纹管采用三维壳单元Shell93，网套采用空间梁单元Beam189，利用耦合和约束理论，在ANSYS中建立金属软管的有限元模型，对金属软管的拉伸、压缩、弯曲等特性分别进行有限元分析，得到金属软管的特性曲线，并将分析结果与试验结果进行比较，证明了有限元建模分析结果以及耦合和约束理论运用的合理性，为金属软管的力学性能和设计分析的进一步研究提供了参考。     

金属软管的非线性有限元分析

运用非线性有限元法,采用三维壳单元Shell93和空间梁单元Beam189,利用耦合和约束方程理论,在ANSYS中建立了金属软管的有限元模型,对金属软管的力学特性进行了分析计算,并将计算结果与实验数据相对照,确定了有限元方法的可靠性,对计算结果进行分析,得出了对金属软管的设计和应用具有参考价值的结论。     

基于ANSYS的金属软管参数化有限元建模方法

选用三维空间梁单元beam189表述网套钢丝,空间壳单元shell93表述波纹管,利用耦合节点的方法建立多层波纹管层与层之间的关系,用拟合理论推导出约束方程建立最外层波纹管与网套之间的关系,在ANSYS中建立金属软管的参数化有限元模型。利用此模型对金属软管进行轴线拉伸和压缩仿真分析,将其结果与试验结果进行对比,证明了有限元模型的可靠性。     

超大型数控船用卷板机床身的结构分析与优化

首先对大型数控船用卷板机卷板过程中床身的受力情况进行了分析;进而在保证床身结构力学特性的前提下,对床身结构进行了简化,建立了超大型数控船用卷板机床身的有限元模型;通过对该有限元模型进行计算分析,得到床身的应力和位移结果,并在分析结果的基础上,以其重量为目标进行了结构优化,使床身结构更趋合理。     

导弹转运车软管的优化设计

将波纹管和网套作为整体的软管作为研究对象,利用有限元分析软件ANSYS平台提供的二次编程语言APDL,建立了导弹转运车金属软管的参数化有限元模型,在此模型基础上,以提高金属软管的使用寿命为目标,对模型的重要参数-过渡波下降高度和波数进行了优化设计,使最高应力下降30％,从而提高了软管的使用寿命,得到了较为合理的金属软管有限元模型,为导弹的安全转运提供了必要的保障;为金属软管的生产设计工作提供了可靠的理论依据和有价值意义的参考.     

带钢高温态横向瓢曲的理论与试验

对连续退火生产线上处于高温态的薄宽带钢的横向瓢曲的生成机理提出一种新的解释,认为传统认知的横向瓢曲是横向温差造成的所谓“热瓢曲”的论断并不正确,带钢横向瓢曲的主因是由于带钢宽向中部局部区域张力集中导致不均匀拉伸变形造成的局部屈曲,即类同于冲压成形中的起皱皱曲变形,并通过解析分析和数值计算研究揭示出带钢横向瓢曲变形过程的力学规律;借鉴YBT试验方法,以冷态下的板料不均匀拉伸试验验证了解析分析方法和数值计算模型的正确性;研究提出了抑制连续退火炉内带钢“热瓢曲”现象的一系列对策措施,用于宝钢股份2#连退机组取得成功。     

金属软管的非线性有限元分析

采用三维壳单元shell93和空间梁单元beam89，运用耦合和约束方程理论，利用ANSYS的参数化设计语言(APDL)对金属软管进行了参数化的三维实体建模。对金属软管的力学特性进行了分析计算，并将计算结果与实验数据相对照，确定了有限元方法的可靠性。根据分析结果，对金属软管的特性进行了总结，结论对金属软管的设计和应用具有重要参考价值。     

Elastic lateral-torsional buckling of circular arches subjected to a central concentrated load

An arch under an in-plane central concentrated radial load is subjected to combined axial compressive and bending actions. When these combined axial compressive and bending actions reach a certain value, the arch may suddenly deflect laterally and twist out of its plane of loading and fail in a lateral-torsional buckling mode. This paper derives analytical solutions for the elastic lateral-torsional buckling load of pin-ended circular arches that are subjected to a central concentrated load, using the principle of stationary potential energy in conjunction with the Rayleigh-Ritz method. Analytical solutions of the buckling load for in-plane fixed and out-of-plane pin-ended arches and for the case of the load acting above or below the shear centre are also derived. The analytical solutions are compared with results of a commercial finite element package ANSYS and a finite element code developed by authors elsewhere for arches with different slendernesses, included angles, and cross-sections. The agreement between the analytical solutions and the finite element results is very good.     

Thermal buckling analysis of annular FGM plate having variable thickness under thermal load of arbitrary distribution by finite element method

In this paper, a finite element formulation is developed for analyzing the axisymmetric thermal buckling of FGM annular plates of variable thickness subjected to thermal loads generally distributed nonuniformly along the plate radial coordinate. The FGM assumed to be isotropic with material properties graded in the thickness direction according to a simple power-law in terms of the plate thickness coordinate, and has symmetry with respect to the plate midplane. At first, the pre-buckling plane elasticity problem is developed and solved using the finite element method, to determine the distribution of the pre-buckling in-plane forces in terms of the temperature rise distribution. Subsequently, based on Kierchhoff plate theory and using the principle of minimum total potential energy, the weak form of the differential equation governing the plate thermal stability is derived, then by employing the finite element method, the stability equations are solved numerically to evaluate the thermal buckling load factor. Convergence and validation of the presented finite element model are investigated by comparing the numerical results with those available in the literature. Parametric studies are carried out to cover the effects of parameters including thickness-to-radius ratio, taper parameter and boundary conditions on the thermal buckling load factor of the plates.     

碳纤维带状弹簧的特性计算及实验

针对空间展开机构轻量化、小型化、简单化等的发展需求,通过理论分析实例设计了碳纤维带状弹簧,并结合有限元模拟及实验对其屈曲特性进行了研究。首先,根据薄壳弯曲理论推导了各向异性材料下碳纤维带状弹簧的弯矩计算公式,并分析了影响其屈曲特性的敏感参数;然后,针对工程需要进行了单根碳纤维带状弹簧的实例设计,并建立了其有限元分析模型,得出了其弯矩-转角曲线;最后,加工出了碳纤维带状弹簧实物并对其屈曲过程进行了实验研究。结果表明:实验测得的该碳纤维带状弹簧的临界弯矩值为1 237.6Nmm,与理论分析及有限元模拟结果符合的较好,最大误差为8.7%,验证了理论分析及有限元模拟的准确性及一致性,为之后碳纤维带状弹簧的设计及应用提供了理论依据及技术支持。     

Wrinkling initiation and growth in modified Yoshida buckling test: Finite element analysis and experimental comparison

Wrinkling is one of the major defects in sheet metal products and may also play a significant role in the wear of the tool. The initiation and growth of wrinkles are influenced by many factors such as stress ratios, mechanical properties of the sheet material, geometry of the workpiece, contact condition, etc. It is difficult to analyze the wrinkling initiation and growth considering all the factors because the effects of the factors are very complex and the wrinkling behavior may show a wide scatter of data even for small deviations of factors. In this study, the bifurcation theory is introduced for the finite element analysis of wrinkling initiation and growth. All the above-mentioned factors are conveniently considered by the finite element method. The wrinkling initiation is found by checking the determinant of the stiffness matrix at each iteration and the wrinkling behavior is analyzed by successive iteration with the perturbed guess along the eigenvector. The effect of magnitude of perturbation on the wrinkling behavior can be avoided by the Newton-type iteration method. The finite element formulation is based on the incremental deformation theory and elastic-plastic material modeling. The finite element analysis is carried out using the continuum-based resultant shell elements considering the anisotropy of the sheet metal. For the verification of the analysis, the postbuckling of columns and circular plates are analyzed by finite element analysis using the bifurcation algorithm introduced in the study, and the results are compared with the exact solutions. In order to investigate the effects of geometry and stress ratio on the wrinkling initiation and growth, a modified Yoshida buckling test is proposed as an improved effective buckling test. In the modified Yoshida buckling test, the dimensions of the sheet specimen are varied to change the stress ratio and the degree of constraint. The finite element analysis is carried out for the modified Yoshida buckling test and compared with the experimental results.     

金属软管的网套及端部过渡波的有限元研究

对金属软管的网套进行非线性有限元分析，由于网套在受力时可以在波纹管上面既滚动又滑动，因此采用空间梁单元Beam189来表征网套的受力特性。将过渡波引入金属软管的有限元模型，对模型的端部进行修正，在此模型上，进行网套的静态特性分析，分析结果与试验结果符合较好，说明了有限元建模的有效性。