子午线轮胎固有频率和阻尼辨识的数值与实验研究

研究了一种轮胎固有频率和阻尼比辨识的数值-实验混合方法。数值分析采用非线性有限元方法对强非线性黏弹性轮胎进行模态分析,给出轮胎有阻尼固有频率和无阻尼固有频率的求解,利用模态分量法辨识出各阶模态下的阻尼比。仿真计算结果和实验结果的对比表明,给出的求解固有频率和阻尼比的方法是可靠的。     

基于ANSYS的蒸发罐模态分析

利用ANSYS软件建立蒸发罐的三维有限元模态分析模型,计算蒸发罐的前10阶固有频率,并给出前三阶结构振型图.根据模态分析的结果对蒸发罐结构的设计提出了一些建议,为工程设计提供有实用价值的参考.     

基于ANSYS轮胎定型硫化机机座的模态分析

介绍了轮胎定型硫化机机座模态的计算方法。通过简化硫化机机座模型,采用ANSYS进行固有频率的计算,并对结果进行分析,为硫化机的后续研究提供了设计依据。     

具有弹簧支承的正交异性层合板模态分析

借助差分法,建立了具有弹簧支承正交异性层合悬臂板的特征方程。数值上计算了具有弹簧支承０°和４５°玻纤／环氧层合悬臂板的模态参数,给出了固有频率和弹簧系数间的关系曲线以及振形特征。分析了固有频率依赖于弹簧系数的特点。进行了无弹簧支承和２种不同弹簧系数支承的模态试验,测定了固有频率、阻尼比和振形等模态参数。对于前６阶固有频率的测定值和计算值符合得较好。     

利用有限元进行轮胎模态分析的新方法

为分析轮胎动态特性建立了更为复杂、细致的轮胎三维有限元模型,考虑了轮胎材料的复杂性,对轮胎进行模态分析,并给出固有频率及相应振型。试验结果与计算结果有良好的一致性。还研究了充气压力对固有频率的影响,得出了允许压力范围内压力增大、固有频率随之增大的结论。     

基于ANSYS的组合管式反应塔的模态分析

对结构和所受载荷都非常复杂的某大型组合管式反应塔建立了有限元模型.采用Lanczos算法对组合管式反应塔进行模态分析,得到其固有频率,从而可以计算反应塔对风载荷和地震载荷的动态响应.     

换热管固有频率的计算

为了确定换热器管固有频率,对换热器管束固有频率进行理论计算和有限元数值模拟。将标准计算法和有限元计算法获得的固有频率进行对比。结果表明,Ansys湿模态分析方法能较好地反映换热管的实际固有频率和振动状态。有限元模拟为获得换热器管束固有频率提供依据。     

纤维增强复合悬臂板模态分析

应用差分法数值上计算了玻纤环氧复合悬臂方板的固有频率和振形。进行了玻纤环氧复合悬臂板的模态试验。确定了模态参数。网格划分为８×８时，计算的固有频率值和试验值一致。本文还探讨了玻纤环氧复合悬臂板模态的尺寸效应．当板的长宽比减小时，模态趋于密集．     

单螺杆挤出机螺杆模态分析及其优化设计

通过ANSYS有限元分析软件,对单螺杆挤出机的核心部件—螺杆部分进行模态分析计算其固有频率,并通过振动试验对仿真结果进行验证,结果表明通过有限元法对挤出机螺杆的模态仿真具有较高的可靠性。获得该螺杆前三阶固有频率后,结合螺杆实际工作状况对螺杆进行优化,采用增加螺杆的起始端固定段长度的方法有效降低螺杆一阶固有频率和振动幅度,避免共振的产生。为实际生产中,降低单螺杆挤出机振动、噪声,获得更加稳定的挤出产物提供新的解决方案,也为学者研究螺杆挤出机提供一种新的方法。     

全钢载重子午线轮胎模态的有限元分析

采用ABAQUS软件对12.00R20规格全钢载重子午线轮胎建立三维有限元模型,并对该模型进行模态分析, 得到了在标准充气压力和额定负荷工况下轮胎的固有频率和相应的振型,同时还研究了气压和负荷对轮胎固有频率的影响.结果表明,在允许充气压力范围内,随着充气压力和负荷增大,轮胎的固有频率提高.轮胎模态的有限元分析能够为研究轮胎动态特性以及轮胎与整车匹配提供理论指导.     

硫化机全焊接横梁振动时效数值分析

采用ANSYS有限元分析软件,通过模态分析和谐响应分析,对1665型双模定型硫化机全焊接横梁的振动时效工艺关键参数（激振力、激振频率及激振点等）进行预测.由模态分析可知,横梁前10阶振动4个优选固有频率中318 Hz的波浪振型较为合理,并据此确定其激振点.通过谐响应分析获得一定激振频率、不同激振力时横梁所受最大动应力分布,并根据国家标准确定激振力取值范围为[300,690] kN.     

Self‐heating of polymeric laminated composite plates under the resonant vibrations: Theoretical and experimental study

The self‐heating effect caused by the energy dissipation during vibration of viscoelastic materials is an important criterion in the evaluation of the structural degradation. In this study the theoretical model of the self‐heating of the polymeric layered FRP plate subjected to the resonant vibration was proposed. The model is based on the complex parameters, which could be obtained in DMA tests. The theoretical model is validated in several experiments. The experiment contains two stages: first, the modal analysis was performed for the evaluation of natural frequencies of vibration and further the specimens were excited to harmonic vibration with their resonant frequencies in the constant strain rate mode. During the second stage the force response and evolution of the temperature distributions on the surface of the specimens were registered. Obtained results allow identifying the self‐heating temperature evolution of the composite and determining the relation of the excitation frequency and self‐heating temperature. Several phenomena observed during the experiments were interpreted following their physical nature. Investigated problem could be applied for predicting the structural life of such composites and in diagnostics and structural health monitoring of the parts and constructions made of polymeric composites. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

船用天线罩的振动响应分析与试验验证

采用ANSYS有限元分析软件,对某船用天线罩进行模态分析及振动响应分析。考察罩体结构的危险区,分析敏感部位的应力、位移和加速度等的时间历程,并且通过振动试验验证仿真分析的正确性。     

Effect of vibration fatigue on modal properties of single lap adhesive joints

As most existing studies focus on developing models and theories describing the static strength of adhesive joints as a function of the fatigue loading, there is a lack of understanding on how the fatigue of the adhesive joint affects dynamic modal properties of the bonded structure. In applications such as automobile components, modal properties are critical in determining their dynamic performances. To investigate the relationship between modal properties of single lap joints (SLJs) and the cyclic-vibration-peel loading, this study first carries out vibration fatigue tests and subsequent modal response measurements using steel–aluminum SLJ specimens. It is experimentally demonstrated that modal frequencies of the SLJ structure tend to decrease with increasing vibration fatigue cycles. Furthermore, it is also shown that this trend is related to the fatigue characteristics of the adhesive layer. The fatigue degradation effects of Young's modulus and contact area between the adhesive and the adherends on modal frequencies are then investigated using a finite element model. Simulation results reveal that dramatic reductions in modulus and contact area values are required to result in the modal frequency shifting observed in experiments, which may not be always realistic. Although the findings in this study are informative, more research effort is needed to further identify the critical reason(s) for the experimental trend of decreasing modal frequencies with increasing vibration fatigue cycles.     

焦炭塔结构的固有频率和振型研究

在传统的直立塔设备固有频率和振型的计算中,将塔设备简化为悬臂梁计算模型,但实际塔的薄壁圆筒结构与梁模型不符,为此对焦炭塔建立有限元分析模型进行模态分析,得到焦炭塔的固有频率和振型,计算分析表明,由于焦碳塔特殊的结构特点使得焦炭塔的振动特性与传统大型直立设备简化为悬臂梁计算模型所得振动特性相比有所不同,因此焦炭塔结构计算中在计及高阶振型与固有频率时,不宜简化为悬臂梁计算模型。     

往复式压缩机管道振动的ANSYS分析

针对常见的压缩机管道振动情况,通过分析得出其主要原因可能是管系结构固有频率与激发主频率相近而造成共振。通过理论计算得到压缩机的前8阶激发主频率,再利用ANSYS分析软件对管系进行模态分析,得到系统的低阶固有频率和振型,从而验证了在较低阶情况下激发主频率与结构固有频率处于共振区。并且在不改变管系主要特征的基础上,给出了简单易行的减振措施,对实践具有重要的指导意义。     

子午线轮胎振动特性实验研究

利用振动实验模态分析的方法，建立了自由悬置和接地状态下轮胎的振动特性模态测试与分析系统，通过轮胎径向激振测试信号的数据处理与分析，提取了各阶的频率及其径向模态振型，分析了轮胎的模态参数随充气压力、负荷变化的规律，为实验方法的研究和轮胎结构设计及车辆的动力性能分析提供指导。     

Free vibration analysis of an adhesively bonded functionally graded double containment cantilever joint

In this study, Genetic Algorithms (GAs) combined with the proposed neural networks were implemented to the free vibration analysis of an adhesively bonded double containment cantilever joint with a functionally graded plate. The proposed neural networks were trained and tested based on a limited number of data including the natural frequencies and modal strain energies calculated using the finite element method. GA evaluates a value generated iteratively by an objective function and this value is calculated by the finite element method. The iteration process restricts us apparently to use directly the finite element method in our multi-objective optimisation problem in which the natural frequency is maximised and the corresponding modal strain energy is minimised. The proposed neural networks were used accurately to predict the natural frequencies and modal strain energies instead of calculating directly them by using the finite element method. Consequently, the computation time and efforts were reduced considerably. The adhesive joint was observed to tend vertical bending modes and torsional modes. Therefore, the multi-objective optimisation problem was limited to only the first mode which appeared as a bending mode. The effects of the geometrical dimensions and the material composition variation through the plate thickness were investigated. As the material composition of the horizontal plate becomes ceramic rich, both natural frequency and modal strain energy of the adhesive joint increased regularly. The plate length and plate thickness were more effective geometrical design parameters whereas the support length and thickness were less effective. However, the adhesive thickness had a small effect on the optimal design of the adhesive joint as far as the natural frequencies and modal strain energies are concerned. The distributions of optimal solutions were also presented for the adhesive joints with fundamental joint lengths and material compositions in reference to their natural frequencies and corresponding modal strain energies.     

Optimal design of an adhesively-bonded corner joint with single support based on the free vibration analysis

This study investigates the three-dimensional free vibration behaviour of an adhesively-bonded corner joint with single support. The modulus of elasticity, Poisson's ratio and density of adhesive were found to have negligible effects on the first 10 natural frequencies and mode shapes of the corner joint. The effects of the geometrical parameters, such as support length, plate thickness, adhesive thickness and joint length, on the natural frequencies, mode shapes and modal strain energies of the adhesive joint were also investigated using both the finite element method and the back-propagation artificial neural network (ANN) method. The free vibration and stress analyses were carried out for the corner joints with various random geometrical parameters so that a suitable ANN model could be trained successfully. The support length, plate thickness and joint length all played important roles in the natural frequencies, mode shapes and modal strain energies of the corner joint, whereas the adhesive thickness for the range of adhesive thickness studied had only a minor effect. The Genetic Algorithm was also combined with the present ANN models in order to determine the optimum geometrical dimensions which satisfied the maximum natural frequency and minimum modal strain energy conditions for each natural frequency and mode shape of the adhesively-bonded corner joint.     

Free Vibration Analysis and Design of an Adhesively Bonded Corner Joint with Double Support

This study carries out the three dimensional free vibration analysis of an adhesively bonded corner joint and investigates the effect of an additional horizontal support to the adhesive corner joint with single support on the first ten natural frequencies and mode shapes. In the presence of a horizontal support the effects of the vertical support length, the adhesive thickness, the plate thickness, and the joint length on the natural frequencies and modal strain energies of the adhesive joint were also investigated using the back-propagation Artificial Neural Network (ANN) method and the finite element method. The natural frequencies and modal strain energies increased with increasing plate thickness, whereas an adverse effect was observed for increasing joint length. Both horizontal and vertical support lengths exhibited similar effects but the adhesive thickness had a negligible effect. The plate thickness and the joint length are dominant geometrical parameters in comparison with both horizontal and vertical support lengths. The proposed ANN models were combined with the Genetic Algorithm in order to determine the optimal corner joint in which the maximum natural frequency and minimum elastic modal strain energy are achieved for each natural frequency and mode shape of the adhesive corner joint and the optimal dimensions were given versus one geometrical parameter.