Pdf experimental stress analysis for materials and. Measurement of internal strainstress fields by means of. Holography is now offered in both sessions of phys 128ab, allowing more students to perform the lab. Holography dh, which mean it is going to be explained afterwards. When a stress is applied, fringes will appear as the displacements occur, and the development of fringes may be observed in real time. You should take this as an opportunity to understand thoroughly what is happening. This site is like a library, use search box in the widget to get ebook that you want. Completing the solution of partially specified problems. Darkfield electron holography for strain mapping at the nanoscale. The experimental setup for o axis holography is shown in fig.
Fullfield stress analysis by holographic phasestepping. Experimental stress analysis an overview sciencedirect. The material in the grating area is modified by periodic alterations in the fibre cores index of refraction. The holography lab is a little different than most experiments in 111 lab in that there is little quantitative analysis to do. For each technique, multiple images must be acquired to reveal quantitative 3d, magnetic or electrical information, in com bination with automation and analysis software, resulting in the need. The theory behind holography is rather straightforward and based on the fact that information recorded in the emulsion of photographic or holographic film is caused by the intensity, not the phase, of the electromagnetic wave incident on the film. Threedimensional stress analysis of a simply supported beam using digital holography and refractive index matching. This film examines the process of holography, types of holograms, and the uses of the hologram for artistic and scientific purposes, as demonstrated by tung h.
December 9, 2014 holographic methods have historically been used to record three dimensional images as well as to. The analysis of stress from the observed fringesis the same as in. The beam emitted by a laser is split into two beams. For experimental stress analysis, the most highly developed common fibreoptic sensor is the fibre bragg grating strain sensor. Holography tim sir louis physics department, the college of wooster, wooster, ohio 44691 april 26, 1999 this experiment used double exposure holography to find the strain on an aluminum can by an outside force. Caustics in a tea cup, dimple formation, class demonstration of caustic experiment. Laser ablation is used for material removal and digital holography measures the displacements produced by the residual stress release around the processed area. A holographic image can be seen looking into an illuminated holographic print by shining a laser through a hologram and projecting a image on the screen. Explain briefly the phenomenon of moire techniques, used for the analysis of stresses. The isochromatic pattern is related to the stress system by the stress optic law. Expose the film for half of the total exposure time while the object has little or no stress applied. Experimental stress analysis has been traditionally appliedthrough a direct or forward approachfor solving structural mechanical problems as an alternative and complementary methodology to. You will end up making a transmission hologram, and a phase hologram that can be viewed with the use of the diode laser in this experiment.
The strain on the can is related to the stress by youngs modulus. In addition, the recorded reflective hologram can be reconstructed with white light. The great development of numerical methods has largely overruled this task. Pryputniewicz worcester polytechnic institute department of mechanical engineering center for holographic studies and laser technology worcester, massachusetts 01609 abstract. For exploratory research, a contactless optical holographic interferometry method was used, allowing a comprehensive picture of the stress state when opening microcracks. A brief introduction is given to holography and a description of specific techniques widely used in this field is provided. Experimental methods modern experimental stress analysis. Venkateswararao3 1mtech student, 2assistant professor, 3professor and head mechanical department, bapatla engineering college, bapatla, guntur, india. User for analysis of vibrating objects, from loudspeakers to parts of jet engines. View enhanced pdf access article on wiley online library html view. Video lecture on experimental stress analysis prof.
Holographic interferometry can be used to detect the optical path length variations in transparent media, that enables, for example, fluid flow to be visualized and analyzed, it can also be used to generate the contours representing the form of the surface. Study the stress pattern of an object by making a hologram with the object subjected to differing amounts of stress possibly a metal rod with a clamp attached. However, the next logical step, the application of the method to the solution of engineering problems, has not followed any significant degree. Experiment 9 holography never look directly into the unexpanded laser beam or its reflection from a mirror surface laser safety the heliumneon lasers which are used with the optel modern optics educational system are of low power rating typically 0. Holography, means of creating a unique photographic image without the use of a lens. An application of holography to complete stress analysis of. This experiment kit employs a semiconductor laser as the light source to generate reflective and transmissive holograms on the recording medium, a photopolymer plate. Stress concentration at a circular hole in a tension field 29 10. Fringe patterns richness of qualitative information. Experimental results on the threedimensional deflection and stress field and the.
This kind of studies are used in aircraft industry like is explained afterwards in the brief history of the holography. Forms of stress function in polar coordinates 26 10. This analysis allows check and compares the two results. It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material, where it gives a picture of stress distributions around discontinuities in materials. Because phase is a relative property, construction of a. Experimental stress analysis an overview sciencedirect topics. The general idea of acoustic holography has led to different versions such as nearfield acoustic holography nah and statistically optimal nearfield acoustic holography sonah. Apart from a three credit 42 lectures first level course on experimental stress analysis, with judicious planning, one can use the material in the book in a variety of ways to suit different audiences like a. Viewing a hologram is like peering through a portal into a threedimensional space in which you can see a threedimensional image, so real that you want to reach out and touch it. An application of holography to complete stress analysis of photoelastic models. This paper deals with the visualization and analysis of interaction of a cutting wedge disintegrator with plastic at low loads. Physics 331a experiment 8 holography revised 16 may 2005. The photographic recording of the image is called a hologram, which appears to be an unrecognizable pattern of stripes and whorls but whichwhen illuminated by coherent light, as by a laser beamorganizes the light.
Furst, np discovered by the hungarian dennis gabor in 1948, holography is based on the concept of interference. A new instrument for measuring the in siru level of stress in bore. Pdf experimental stress analysis for materials and structures. To provide an introduction to the basic principles and methods of experimental stress analysis. Experimental stress analysis an overview 1,333 views. This experiment uses a 658nm diode laser as a source of coherent light which irradiates the objects, and also provides a reference beam of uniform amplitude and phase. Oct 18, 2016 the video lecture will explain how a hologram is made. These concepts have to be well known for making after the experiment. Experimental stress analysis has been traditionally appliedthrough a direct or forward approachfor solving structural mechanical problems as an alternative and complementary methodology to the theoretical one. Creating your own illusion lab manual sarah honorowski 01, shialing kwa 01 and shane smith 02. These stresses cause in any plane passing through the given point and inclined at an angle. An experimental model was set up for the purposes of the research. Photoelastic holographya modern tool for stress analysis.
Nobel prize winner dennis gabor, holographys inventor, saw the film after it was made and said it was the. Isochromatics and isoclinics quarter wave and half wave plates b. Experimental stress analysis video course course outline the course covers the basic aspects of experimental stress analysis that includes exhaustive treatment of the most versatile techniques like photoelasticity and strain gauges and also a brief introduction to the emerging techniques like digital image correlation. Experimental stress analysis hand written notes mechanical. One beam is expanded and sent onto a high resolution recording medium. Holographic interferometry features, advantages and. Holography 1 holography introduction and background the aesthetic appeal and commercial usefulness of holography are both related to the ability of a hologram to store a threedimensional image. It will explain the recording and reconstruction processes in holography.
Examples of the applications are given to demonstrate this usefulness in the study of typical problems such as vibration analysis and structural analysis. Derived from the greek word holos meaning whole, the term hologram means simply a complete picture. For a thorough explanation of holography and its many applications, the reader may consult any of several standard texts on the subject e. The technique of holography was greatly improved after 1961 when laser was used as the light source. The student is to become familiar with the theory and practice of common experimental stress analysis. Fullfield stress analysis by holographic phasestepping implementation of the photoelasticcoating method. Jun 14, 20 finite element analysis more recent method of stress analysis, generallydeveloped in 1956 in the aircraft industry was the finiteelement method fem. The possibility of recording a photoelastic pattern with holography was first suggested in the literature in 1951. The student is to become aware of the overall concepts of stress strain analysis by experimental means. For analysis of the general threedimensional state of stress at a point and from an analysis of the change in index of refraction with the direction of light propagation in the stressed material, it can be shown that above equations can also be used for secondary.
Modern experimental stress analysis wiley online library. The techniques and principles of holography have been modi. Kizler opportunities and limitations of thermoelastic stress analysis 499 55. Holographic interferometry method for assessment of. As the test object is stressed, fringe patterns in the birefringent material represent. Handson laboratory exercises are provided to illustrate and strengthen the students knowledge of experimental stress analysis methods. An average twofold tension increment was observed in the experimental conditions. For audio rendition, the wave field synthesis is the most related procedure. Each of these stresses can be calculated from static equilibrium equations. This paper deals with the quantitative interpretation of timeaverage holograms of vibrating objects. The name for the technique that was developed comes from the greek word holos, meaning whole, and gramma, meaning message.
However, the next logical step, the application of the method to the solution of engineering problems. A new experimental stress analysis technique or wide application 479 53. It is a physical structure that diffracts light into an image. The analytical and fea results are compared and validated with experimental results. Photoelasticity describes changes in the optical properties of a material under mechanical deformation. Holography is the science of making holograms which are usually intended for displaying three dimensional images. Atomic holography has evolved out of the development of the basic elements of atom optics. Strain measurements and stress analysis download ebook. Digital holography, index matching, threedimensional stress analysis, rapid prototyping model. Despite of the fact that several works have reported the way how the digital holographic imaging systems deal with the frequency of the imaged objects, all of them are limited to computer modelling.
Click download or read online button to get strain measurements and stress analysis book now. Holography is a technique whereby one wavefront can be recorded and subsequently reconstructed without the presence of the original wavefront. Experimental study of frequency response in digital holography. This sensor grating is located in an optical fibre. The ebook covers exhaustively the famous techniques like photoelasticity and strain gauges and provides a decent exposure to moire, brittle coatings, holography, speckle methods, thermoelastic stress analysis, digital image correlation, caustics and coherent gradient sensor. How hologram is made or what is holography duration. As explained earlier the aim of this work is also the same, which is to devise a. Introduction to brief introduction to speckle interferometry, shearography, tsa, dic shearography, thermoelastic stress analysis tsa, and caustics digital image correlation dic and caustics. When reconstructing the original wavefront from the recording, a three dimensional image is observed. Though holography is simple enough for a novice to do in his or her basement, there are still a great number of factors in the process that can ruin the holograms.
Governing equations for threedimensional elasticity problem 5 3. Advancements in holographic photoelasticity springerlink. Threedimensional stress analysis of a simply supported. The normal stress is maximum or minimum when a8 o and for this case rbo the shearing stress vanishes. Time average holography in vibration analysis ryszard j. The subject experimental stress analysis is mostly taught in the fourth year of the mechanical engineering course. Measurement of internal strainstress fields by means of holography. Mckelvie some practical limits to the applicability of the thermoelastic effect 507. Holography modern physics lab, ucsd department of physics written by michael pollack theory. Several assumptions have been made to derive the following equations for circumferential and longitudinal stresses. Pdf fullfield stress analysis by holographic phasestepping.
Laser ablation is used for material removal and digital holography measures the. A holographic procedure is proposed in which an immersion tank is used to simplify the doubleexposure technique for twodimensional photoelastic models and slices from frozen stress models. Holographic interferometry an overview sciencedirect. Overview of experimental stress analysis, stress analysis analytical, numerical and experimental approaches, specific domain of these approaches, advantages and disadvantages. Aerospace engineering, applied mechanics, civil engineering, engineering design, material science, mechanical engineering,naval architecture. Photoelasticity provides a visual method of observing the strain on an object by viewing the effects of polarized light on a birefringent doublerefracting material bonded to the object. Determination of strain and stress in an elastic body by. The principles of holography may be illustrated by the experimental apparatus. Laboratory analysis of settling velocities of wastewater particles in seawater using holography by rueenfang theresa wang eql report no. Bending of a bar or beam stress analysis thermal expansion of an aluminum cube ndt, irreplaceable artifacts changes in phase of light beam density of gas, fluids and solids frozen fringe patterns. The most frequently used holographic analysis technique. Stress analysis in restorative dentistry slideshare. Holographic interferometry hi, which provides interferometric comparison of real objects or events separated in time and space, is a technique of unparalleled applications.
Course organisation modules titles lectures hours 1 overview of experimental stress analysis 110 10 2 transmission photoelasticity 1123 3 introduction to three dimensional photoelasticity. Pdf residual stress evaluation in ceramic coating under. Optical methods work as optical computers, direct information provided by various experimental methods brief description, visual appreciation of field information listing. The success of doubleexposure holography as an interferometric technique for experimental stress analysis has lead to several recent publications dealing this paper describes the extension of current theory to include the effect of an intensity difference between the light used during the first exposure and that used during the second exposure. This research intended to evaluate stress transmission in dog mandibles, through holographic interferometric double exposition method, in such conditions. In this paper, we present an experimental study of the frequency response in offaxis numerical reconstruction of digitally recorded holograms dh.
Cumrnings use of the thermoelastic technique in experimental stress analysis 489 54. Integration of laserspeckle and finite element techniques of stress analysis. Unlike ordinary photographs, holograms record both phase and amplitude information. In this case an atom inside the sample is excited by an external xray source. In the ensuing years, the capabilities and limitations of the method were examined, discussed and refined. T lyubenova1, e stoykova1, b ivanov1, w van paepegem2, a degrieck2 and v sainov1. Introduction to stress analysis by the photostress method. Introduced by richard courant initially, this technique was used widely only inaerospace engineering, but slowly due to theflexibility of the method to model any complexgeometries and provide. It is also important the role of the finite element method fem in this study. We describe a system suitable for the evaluation of residual stress in ceramic coating under industrial conditions. Stress analysis of process pipe line systems asme b 31. Holographic interferometry in experimental mechanics pp 129157 cite as. Photoelastic experiments also informally referred to as photoelasticity are an.
Holography october, 2006 overview since the last writing 2002, many changes and improvements have been made during the past few years. Furthermore, hi can be performed with one, two, or more reference waves, which can be of the same or different wavelengths. Using doubleexposure holographic techniques to evaluate the. Summary a two wave systems frozen or live fringes used to analysis movement, also stress and distortion. Application of holographic interferometry in the analysis. Once explained a brief summary of the history of the finite element method it is. When a hologram is made, a coherent beam of light is divided so that one beam the reference beam falls directly onto a piece of photographic lm and another beam the object beam is formed from the light that is scattered by an object and falls onto the same piece of lm.
I have uploaded the pdf ebook file and handwritten lecture notes on experimental stress analysis for easy downloading below. The analysis made about fringes patterns on the surface of jaw and dental structures. Experimental stress analysis, the goal of cee 4160 5160. The optics table has been divided into two partitions which allows a specific setup to remain intact. Hologram interferometry, steps in a double exposure hologram.