激光超声检测蜂窝材料内部缺陷的数值有限元模拟
关键词 蜂窝材料 激光超声 有限元方法
毕业设计说明书（论文）外文摘要
Title Numerical simulation of the laser ultrasonic testing of honeycomb material internal defects
Abstract
The laser supersonic none destructive method the examination technology is the material none destructive method the examination one important method, is one important examination method which the present people pays attention. The tradition none destructive method the examination method to have the certain limitation, in certain bad examination environment or was measured the detected objects radioactive, has not been able completely to answer the purpose. In the process of manufacture and use of honeycomb material, the honeycomb material produce detect is inevitable. In order to increase the service life of materials and to improve safely factor, we should be able to know the structural characteristics of the material and the stress change at any time. In this article some of the methods of the detection of honeycomb material internal defects is described, and described the laser ultrasonic testing technology advantages, compared to other detection technique. By use Finite element method to build honeycomb material models for numerical simulation of laser ultrasonic testing of honeycomb material defects within. Then by analysis the temperature field and time-domain waveform of laser ultrasound to carried out theoretical studies of the ultrasound propagation in the material.
Keywords honeycomb material laser ultrasonic Finite element method
目 录
1 引言 1
1.1 蜂窝材料的应用及缺陷检测 1
1.2 检测复合材料内部缺陷的意义 2
1.3 本文主要的研究工作 3
2 激光超声无损检测技术 3
2.1 激光超声概述 3
2.2 激光超声数值模拟发展 4
2.3 激光超声检测技术 5
3 激光超声检测蜂窝材料的有限元模拟 6
3.1 网格划分和时间步长的选取 6
3.2 激光作用的力函数 8
3.3 激光辐照蜂窝材料的模型构建 8
3.4 激光辐照蜂窝材料的数值模拟结果及讨论 9
总 结 14
致 谢 15
参 考 文 献 16
1 引言
1.1 蜂窝材料的应用及缺陷检测
日月如梭，科学技术也随着时光的流逝而不断地进步创新。复合材料和纳米材料是目前国际上两类极受人们关注的、在工业上具有很大应用潜力和正在迅速发展的新型机构材料。先进复合材料（ACM）具有比强度高、比模量打、抗疲劳性能好、膨胀系数低以及破损安全性好等一系列优点，能够满足航天技术轻量化、长寿命和高可靠的特殊要求，也已经成为航天技术领域不可缺少的重要结构材料。蜂窝夹层结构是复合材料的一种特殊类型。蜂窝夹层结构的主要特点是上、下板的材料厚度一般情况下均相同，而且比蜂窝芯子高度小的多，面板材料的强度和刚度一般均较高[1].蜂窝材料主要由蒙皮、蜂窝芯和粘接剂组成。蒙皮一般由玻璃布、胶合板、纤文板、薄铝板、铝合金板或钢板组成。蜂窝芯一般由纸、玻璃布、铝合金或芳纶纸等组成，其网格形式有正吹冰边形、菱形或正方向等。虽然蜂窝材料如今在多个领域得到大量的应用，但是其在制作和使用的过程中容易形成缺陷，而这些缺陷的存在严重制约了蜂窝材料的应用。因此，我们对蜂窝材料的缺陷的检测势在必行。