基于有限元的阶梯形变幅杆特性研究
文献类型：学位论文
| 作者 | 贾杨 |
| 学位类别 | 博士 |
| 答辩日期 | 2005 |
| 授予单位 | 中国科学院声学研究所 |
| 授予地点 | 中国科学院声学研究所 |
| 关键词 | 阶梯形变幅杆 振动特性 有限元 过渡段 导波 |
| 其他题名 | Study of vibration performance of stepped ultrasonic horn by finite element method |
| 中文摘要 | 本文采用有限元的方法，利用有限元软件ANSYS计算，比较全面地研究了在功率超声中广泛应用的阶梯形变幅杆的特性。对部分计算结果作了实验验证。本文主要做了如下几方面的工作。本文依据解析一维近似理论，利用MATLAB编制程序，比较系统地全面地分析研究了不带过渡段和带过渡段的阶梯形变幅杆的谐振频率。给出了其谐振频率特性粗略的一般规律，并将其作为有限元研究的主要参照。用有限元方法，研究了阶梯形变幅杆谐振频率随粗细段长度比和粗细段截面积比的变化规律，研究了放大系数随粗细段长度比的变化规律。用有限元软件计算了一系列圆柱棒，阶梯形变幅杆，带直圆锥过渡的阶梯型变幅杆的多阶纵振动模式谐振频率。与一维解析理论的结果比较，在变幅杆某些尺寸情况下两种方法的结果相符，由此评估了一维理论解析法的适用范围。用有限元方法研究了阶梯形变幅杆特性随过渡段形状和尺寸变化的一些规律，分析了过渡段对阶梯形变幅杆的声学性质的影响。分析了几组不同变幅比带不同过渡段的阶梯形变幅杆，其中选择了圆函数过渡和直圆锥过渡两种过渡形式。算出的一阶振动模式谐振频率和振幅放大系数与已有的理论以及实验结果符合较好。计算了变幅杆粗细端分界面上的应力及其分布，数据表明过渡段可以显著改善粗细分界面上的应力集中，同时也会较大的改变变幅杆的振动特性。对部分变幅杆的谐振频率进行实验测量，测量值与有限元计算结果符合得非常好，有力的证明了有限元法的准确性和有效性。本文用有限元方法，对设计优化大尺寸超声振动体进行了很好的尝试。以超声塑料焊接系统的上模作为例子，用有限元计算对其振动进行分析并控制，通过开槽等方法对焊头优化，获取了很好的效果。本文还提出了一种测量具体材料的杨氏模量和泊松系数方法。 |
| 英文摘要 | Stepped ultrasonic horn is widely used in application of high intensity ultrasound. The vibration performance of stepped ultrasonic horn is studied by using the finite element method (FEM) comprehensively. Some FEM results are verified experimentally. Following are main points in this paper. For giving reference to FEM, rules on resonant frequencies of stepped ultrasonic horn with and without taper-transitional section are analyzed systematically by programs written in MATLAB codes according to one-dimensional theory. The rules of frequency variations and amplitude gains of stepped ultrasonic horns with different length ratio and section area ratio are investigated by using FEM software ANSYS. 1st order to 6th order longitudinal vibration resonant frequencies of circular rods, stepped ultrasonic horns and stepped ultrasonic horns with taper- transitional section are calculated by ANSYS. For horns in some geometry size, results of one-dimensional theory accord with the ones of FEM well. Based on these, the applicability and validity of the 1-D approximate theory are estimated. The influence on vibration performance of stepped ultrasonic horns stemming from the transitional section with different shape and geometry are studied by FEM. A series of stepped ultrasonic horns with different transitional section, such as cyclo-transitional section and taper- transitional section, are analyzed by FEM. Resonant frequency and amplitude amplification from FEM are consistent with the ones of the existent theory and experiments. Distribution of stresses deduced by post processor of ANSYS justified that transitional sections can obviously reduce the stress concentration on the cross section and change the vibration perfonnance of stepped horns obviously. Veracity and validity of FEM are verified by measuring frequencies of parts of ultrasonic horns. A block horn, which is used for plastic welding of large, flat, rectangular parts, is analyzed by FEM. By being slotted through both its width and thickness, the rectangular horn gets amplitude uniformity and improved vibration performance across its working face. A method of measuring Poisson modulus and Yang's module is presented in this paper as well. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 54 |
| 源URL | [http://159.226.59.140/handle/311008/1008]  |
| 专题 | 声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文 |
| 推荐引用方式 GB/T 7714 | 贾杨. 基于有限元的阶梯形变幅杆特性研究[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2005. |
入库方式： OAI收割
来源：声学研究所
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