Optical Methods in Experimental Solid Mechanics

432 Pages·2000·44.117 MB·English

by  Karl-Hans Laermann (eds.)

CISM COURSES AND LECTURES
Series Editors:
The Rectors of CISM
Sandor Kaliszky- Budapest
Mahir Sayir - Zurich
Wilhelm Schneider- Wien
The Secretary General of CISM
Giovanni Bianchi - Milan
Executive Editor
Carlo Tasso - Udine
The series presents lecture notes, monographs, edited works and
proceedings in the field of Mechanics, Engineering, Computer Science
and Applied Mathematics.
Purpose of the series is to make known in the international scientific
and technical community resuits obtained in some of the activities
organized by CISM, the International Centre for Mechanical Sciences.
INTERNATIONAL CENTRE FOR MECHANICAL SCIENCES
COURSES AND LECTURES -No. 403
OPTICAL METHODS
IN EXPERIMENTAL SOLID MECHANICS
EDITED BY
KARL-HANS LAERMANN
BERGISCHE UNIVERSITY OF WUPPERTAL
~ Springer-Verlag Wien GmbH
This volume contains 266 illustrations
This work is subject to copyright.
All rights are reserved,
whether the whole or part of the material is concerned
specifically those of translation, reprinting, re-use of illustrations,
broadcasting, reproduction hy photocopying machine
or similar means. and storage in data hanks.
© 2000 hy Springer-Verlag Wien
Originally published by Springer-Verlag Wien New York in 2000
SPIN 10763422
In order.to make this volume available as economically and as
rapidly as possible the authors' typescripts have been
reproduced in their original forms. This method unfortunately
has its typographical limitations hut it is hoped that they in no
way distract the reader.
ISBN 978-3-211-83325-4 ISBN 978-3-7091-2586-1 (eBook)
DOI 10.1007/978-3-7091-2586-1
PREFACE
Recent developments and achievements in measurement techniques
especially in optical and electro-optical methods like holography, shearography,
speckle interferometry, grid-methods, modern modification of photoelasticity
and photoviscoelasticity have opened new fields of applying experimental
analysis in solid mechanics, in research as well as in industrial practice.
Combined with computer techniques in digital image processing, data recording
and data evaluation complex measuring systems can be realised nowadays with
the possibility off ar-reaching automation of the entire analysing processes.
The sensitivity and the high resolving power of recording equipment
requires thorough investigation of any effects on the precision and reliability of
the measurements. Therefore it is necessary, to deal with the physics and the
theories of the measurement methods in order to interpret the observed
phenomena correctly. Furthermore proper algorithms must be available to
evaluate the measured data to get the finally wanted infonnation, which generally
do not coincide with the quantities taken from the measurements originally. This
fact requires complementary scientific considerations of the theories concerning
the problems to be analysed. At least the combination of experimental and
mathematical/numerical procedures for evaluation and interpretation, known as
"hybrid technique", demands additional contemplation.
The lectures cover
i. the theory and the physics of advanced optical measuring methods and
problems of experimental performance, recent achievements in 2- and
]-dimensional linear/non-linear photoelasticity including photovisco-
elasticity, Moire- and grid-techniques, illfe1jerometric methods (holography.
speckle inte1.ferometry, shearography):
11. the theory (~f digital image processing and its pe1jomwnce. data-recording,
-compression, -processing, -l'isuali:::ation:
iii. mathematical and numerical procedures. il{formatics for emluation of
measured, digiti:;,ed data.
As the co-ordinator (~f the CISM-course "Modem Optical Methods in
Experimellfal Solid Mechanics .. and the editor (~f the lecture notes I grate.fitlly
thank the lecturers/autlwrsfor the e.fjectil'e co-operation and thorough re\·ising
the manuscripts. the resident Rector. the General Secretary. the ChiefEditor.
and explicitly the st(!ffmemhers (~f CISM Secretariat.f(Jr support and excellent
organisation (~f the course. Many thanks to the Springer-Verlag .f(Jr publishing
the lecture notes.
Karl-Hans Laennann
CONTENTS
Page
Preface
I. HYBRID TECHNIQUES IN EXPERIMENTAL
SOLID MECHANICS
by K-H. Laermann __ __________ _
1. INTRODUCTION___________________________________________________________________________________ 2
I .1 Roll and importance of optical methods in experimental
Mechanics
1.2 Influence and effect on safety and reliability of structures
1.3 Presumption of applicability in industrial practice
2. PRINCIPLE OF HYBRID TECHNIQUES ______________________________________________ 7
3. NON-LINEAR PHOTOELASTICITY_ ___________ __ __ ___ ___ _____ _____ __ ____ __ __ __ __ __ __ 13
3. I N on-1 in ear stress-strain relations
3.2 Non-linear relation between stress state and birefringence
3. 3 Iterative discrete solution
3.4 Determination of material response
3.5 Examples of application
4. PHOTO VISCOELASTICITY _____________________________________________ . __ _ _ _ _ _ _ _ _ _ _ _ 25
4.1 Preliminary remarks
4.2 Basic relations between the stress tensor and the refraction tensor
4.3 Determination of the optical relaxation function
4.4 Solution of the VOLTERRA's integral equation
5. EVALUATION OF PHOTOELASTICIVISCOELASTIC
MEASUREMENTS BY MEANS
OF BOUNDARY-ELEMENT METHOD __________________ _ 34
5. I Mathematical basis
5. 2 Plane plates with inclusions
5. 3 Application to two-dimensional photoelasticity
5.4 Elastic/viscoelastic response of material
6. ANALYSIS OF 3-D-STRESS-STRAIN STATES BY MEANS
OF DISCRETE BOUNDARY-INTEGRAL·-------·-----··········----·-----·····-···-· 47
6.1 Determination of the surface displacement
6.2 Mathematical basis
6.3 The reduction procedure
6.4 Example of application
7. ANALYSIS OF 3-D-STRESS-STRAIN STATES
BY COMBINING ESPI WITH FEM ________________ ____ -------------------------------- 56
7. I Determination of surface displacements by ESPI
7.2 Evaluation of the experimental data by means of FEM
7.3 Example of application
8. REMARKS GENERALLY TO CONSIDER IN PERFORMING
EXPERIMENTAL MECHANICS ____________ ------·-______________________________________ 64
8.1 Multidisciplinary character of experimental mechanics
8.2 Necessity of advanced theories of mechanical problems
8.3 Inverse problems in final evaluation
8.4 Transfer problems related to measuring systems
9. REFERENCES______________________________________________________________________________________ 70
II. RECENT DEVELOPMENTS IN 3-D-PHOTOELASTICITY
AND GRATING STRAIN MEASUREMENT
by A. Lagarde. _____ . __________ .. ___ .. _.. ... __ .. ____ . ______________________________ . ________ ...... __ . ______ . 73
I. THREE DIMENSIONAL PHOTOELASTICITY ................................... 74
1.1 Present practice and new possible way
1.2 Propagation of the light wave through photoelastic medium
1.2.1 The classical scheme
1.2.2 ABEN schematisation
1.2.3 Hypothesis for a thin slice
1.2.4 Discrete analysis into thin slices
1.3 Whole-field analysis with a plane polariscope
1.4 Whole-field optical slicing method
1.4.1 Method on the contrast measurement of one recording intensity
field
1.4.2 Method based on the variance measurement of the combination
of three recording intensity fields
1.5 Separation of isoclinic and isochromatic patterns of the slice.
Isostatics plotting
1.6 Conclusion and perspectives
1 . 7 References
2. GRATING STRAIN MEASUREMENT_ ________________________________________________ 87
2.1 Introduction
2.2 Local strain measurement
2.2.1 Recall: Description on the move of a continuous medium
2.2.2 Principle of the method
2.2.3 Grating realisation
2.2.4 Measurement by optical diffraction
2.2.5 Measurement by spectral analysis
2.3 Improvement of the accuracy
2.3.1 The tools of the accuracy
2.3.1.1 The phase shifting method
2.3.1.2 The spectral interpolation method
2.3.2 The device
2.4 Holo-grating analysis
2.4.1 Holo-grating recording
2.4.2 Holo-grating reconstruction
2.4.3 Application to the ductile fracture
2.5 Local strain measurement in dynamic
2.5.1 Diffraction in oblique incidence
2.5.2 Principle of the method
2.5.3 Implementation
2.5.4 Experimental tests
2.5.5 Hopkinson bar investigation
2.6 Local strain measurement on cylindrical specimen
2. 7 Conclusion and perspectives
2. 8 References
III. AUTOMATED IN-PLANE MOIRE TECHNIQUES
AND GRATING INTERFEROMETRY
by M. Kujawinska_ ... __ . ___ . __ . __ .. __ . ______ . __ .. _.. ___ . _.. _.. ........ _.. _. .................. _......... 123
l. THE BASIC RULES IN FULL-FIELD GRID TECHNIQUES _____ . __ . ___ . __ 124
1 . I Basic grid moire technique
1.2 Fixed grid method
1.3 Principles of grid theory
1.3.1 Formation of moire in incoherent light
1.3.2 Interferometric techniques
2. GRID (GRATING) TECHNOLOGY ................................................... 132
2.1 Amplitude grids
2.2 Phase gratings
3. PRINCIPLES OF AUTOMATIC ANALYSIS OF RESULTS ................ 136
3. I Introduction
3.2 Fringe pattern analysis
3.2.1 Phase shifting methods
3.2.2 Fourier transform method
3.3 Phase unwrapping
3.4 Calculation of strain fields
4. THE MOIRE FRINGE METHOD. ...................................................... 144
4.1 Physical superimposition of gratings
4.2 Projected superimposition
4.3 Double exposures and moire photography
5. GRATING (MOIRE) INTERFEROMETRY ........................................ 148
5. I Introduction
5,2 Principle of grating interferometer
5.3 Grating interferometer systems
5.3.1 The laboratory system (LGI)
5.3.2 The workshop portable system
5.3.3 Fibre optics grating interferometer sensor (FOS)
5.3.4 Waveguide grating microinterferometer (WGI)
5.4 Engineering features of automated grating interterometers
6. MATERIAL ENGINEERING AND MICRO-MECHANICS !58
6.1 Introduction
6.2 Local approach to material engineering
6.3 Microelements testing
6.4 Electronic chips and packages studies
6.5 Mechanical/material joint testing
7. HYBRID METHODS OF RESIDUAL STRESS ANALYSIS _________ _ 175
7.1 Introduction
7. 2 Objects of measurements
7.2.1 Railway rail
7 .2.2 Laser beam weldment
7.3 Experimental set-up and procedure
7.4 Experimental results and discussion
7.4.1 Residual strain determination for railway rails
7 .4.2 Residual stress determination in laser beam weld
7.5 Conclusions
8. CONCLUSIONS AND FUTURE POTENTIALS_ 187
8.1 Moire in relation to other methods
8.2 Direction of development and future potentials
9. REFERENCES ___ ... __ .... ________ . ___ .. _________________ .... _______ .. __ ._ ..... ________ . _________ _ 189
IV. INTERFEROMETRIC METHODS
by W. Jiiptner ___ . ______ --·------------__ ·--------·--------·-·----·-·---___________________________ .. -·--· _ 197
I. INTRODUCTION_ _________________ .. _.. __ ...... ____ ... ____________________ .. _.. ___ .. _.. ______ . __ 198
I .I Historical remarks
1.2 Properties of electromagnetic waves
1.3 Interference of waves
I .4 Diffraction of light
I . 5 References
2. HOLOGRAPHIC INTERFEROMETRY -------------------------------------209
2.1 Holography
2.1.1 Fundamentals of holography
2.1.2 Amplitude and phase holograms
2.1.3 Types of holograms
2.1.4 Stability requirements for recording holograms
2.2 Holographic interferometry
2.2.1 Fundamentals of holographic interferometry
2.2.2 Evaluation of interference pattern
2.3 Application of holographic interferometry
2.3.1 Non-destructive evaluation by holographic interferometry
2.3.2 Fracture mechanics
2.3.3 Vibration analysis
2.4 References