cmu大学郑州大学硕士论文模板

设计并搭建了经典迈克逊干涉仪差分检测系统和偏振迈克逊干涉仪差分检

测系统， 并对两套系统的工作原理进行了介绍。两套检测系统均包括声表面激

发单元、声表面波检 测单元和信号采集与处理单元，其中偏振系统在传统系统

的基础上增加了起偏器、

λ

/4

波片和

λ

/2

波片 ，

并将分光镜替换为偏振分光镜，

故偏振系统中的光束为偏振光，使得偏 振系统在消除共模噪声和增强信号方面

具有显著效果。同时设计了

FIR

数字低通滤波器，较好地滤除了系统检测到的

声表面波信号中的高频噪声 。

关键词：

激光声表面波表面裂纹有限元仿真经典

/

偏振式迈克尔逊干涉仪；

I

Abstract

Abstract

As the industrial technology is developing very fast and gets advanced very much in

recent

years,

the

required

quality

of

media

and

materials

gets

higher.

And

the

surface/subsurface

integrity

and

completeness

of

the

materials

decide

the

performance and working life of the equipment and devices. Besides, accompanying

the

fast

developed

industrial

technology,

the

air

condition

gets

worse

and

water

resources get polluted. As a result, some disease cases increase especially skin disease.

Recently,

the

morbidity

of

skin

disease

in

China

is

increasing

year

by

year,

and

it

becomes a trend that more

young people

get

affected. Therefore the nondestructive

detection for surface cracks and pathological changes on skin is very important and in

great

need.

Laser-induced

Surface

Acoustic

Waves

technology

as

a

nondestructive

detection

approach

has

shown

promising

results

in

the

characterization

of

surface

feature. The work done in this dissertation is following:

1,

the

state-of-art

of

the

Laser-induced

Surface

Acoustic

Waves

technology

is

explored.

The

shortness

of

the

current

researches

and

technologies

are

concluded,

based on which, the research content and goal is finally determined.

2,

FEM

simulations

under

thermal-stress

analysis

mode

are

conducted

by

the

software

of

ANSYS

to

explorer

the

effects

that

pulse

laser

parameters,

including

pulse energy, rise time, beam radius, absorption and scattering coefficients, have on

the

generated

Surface

Acoustic

Waves.

And

the

range

of

parameters

to

generate

Surface Acoustic Waves with big amplitude and high frequency components are given.

Pulse

laser

with

these

parameters

is

applied

on

skin

with

melanoma.

Through

the

dispersion

curves

of the detected signals,

the relation between the mesh

size

of the

skin model and the minimum detectable melanoma is found.

Key

words:

Laser-induced

Surface

Acoustic

Wave,

Surface

crack,

skin,

FEM

simulation, Classical/polarized Michelson interferometer.

II

目录

目录

摘要

............................. .................................................. ............................. I

Abstract

.

............... .................................................. .................................... II

目录

............................. .................................................. ...........................

I

II

1

绪论

................................. .................................................. .....................

4

1.1

激光声表面波技术

.

........ .................................................. ..............................

4

1.1.1

声表面波技术简介

.......... .................................................. ....................................

5

2

工作总结与展望

.................................................. ..................................

7

2.1

工作总结

.

............ .................................................. ..........................................

7

2.2

工作展望

.

............ .................................................. ..........................................

7

参考文献

....... .................................................. ...........................................

8

个人简历、在学期间发表的学术论文与研究成果

................................

9

致谢

......... .................................................. ...............................................

1

0

III