High Sensitivity Moiré

Post, Daniel; Han, Bongtae; Ifju, Peter

doi:10.1007/978-1-4612-4334-2

Cited by 447 publications

(219 citation statements)

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“…Z(x, y) represents the height of any coordinate on the moiré pattern, and it is linearly proportional to the ordinal of moiré fringes, N. This is to say that the change of every fringe represents the change of a fixed height. This study uses this relationship to measure the topographic map of the surface height of a test piece and the displacement in height [8].…”

Section: Shadow Moiré Methodsmentioning

confidence: 99%

Research on Subcutaneous Pulse Shape Measurement by Near-infrared Moiré Technique

Chen¹,

Liu²,

Du³

et al. 2015

Journal of the Optical Society of Korea

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A pulse is generated when the heart pumps blood into the arterial system. The heart pumps blood only when it contracts, not when it relaxes; therefore, blood enters the arterial system in a cyclical form. Artery beating is visible in some parts of the body surface, such as the radial artery of the wrist. This paper mainly uses the feature in which near-infrared spectroscopy penetrates skin to construct a non-invasive measurement system that can measure small vibration in the subcutaneous tissue of the human body, and then uses it for the pulse measurement. This measurement system uses the optical moiré principle, together with the fringe displacement made by small vibration in the subcutaneous tissue, and an image analysis program to calculate the height variation from small vibrations in the subcutaneous tissue. It completes a measurement system that records height variation with time, and that together with a fast Fourier transform (FFT) program, they can convert the pulse waveform generated by vibration (time-amplitude) to heartbeat frequency (frequency-amplitude). This is a new and non-invasive medical assistance system for measuring the pulse of the human body, with the advantages of being simple, fast, safe and objective.

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Section: Shadow Moiré Methodsmentioning

confidence: 99%

Research on Subcutaneous Pulse Shape Measurement by Near-infrared Moiré Technique

Chen¹,

Liu²,

Du³

et al. 2015

Journal of the Optical Society of Korea

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“…The orientation of the tensile loading axis with respect to the lattice axes of the parent phase is (0.087, -0.796, -0.605 ). The basic principle of Moire5 interferometry is described in detail in the book of Post, D., Han, B. and Ifju, P. [5]. In this method, the grating deforms together with the underlying specimen.…”

Section: Methodsmentioning

confidence: 99%

“…Moire interferometry has been used widely in the experimental mechanics to perform various kinds of in-plane displacement measurement [5]. It has several excellent properties like real-time, high sensitivity to in-plane displacement, high spatial resolution and high quality fringe patterns.…”

Section: Introductionmentioning

confidence: 99%

On the Full-Field Deformation of Single Crystal CuAlNi Shape Memory Alloys—Stress-Induced β₁ → γ'₁ Martensitic Transformation

Zhang

Sun

et al. 1997

J. Phys. IV France

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Using high sensitivity Moir6 interference technology, the full deformation fields about the stressinduced martensitic transformation P, + ' )' ; of single crystal CuAlNi shape memory alloys (SMAs) are obtained.A straight and sharp interface between martensite and parent phases and its motion during transformation process are clearly observed. The elastic anisotropic properties of the crystal are also quantitatively characterized by this technique. The results show that there is no deformation incompatibility between the two phases, which is different from that of pseudoelasticity where another stress-induced martensitic transformation PI occurs. The present results provide an accurate experimental solution for the phase transformation problem in solids.

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“…For each different wood sample a specific moiré pattern would be generated due to their different mechanical behavior allowing a closely specie identification. By employing the whole field subtracting method as defined by POST et al (1994), an isostrain field could be defined which would indicate the occurrence of stress concentration. ALBIERO et al (2004) affirm that technique of shadow moiré allied with whole field subtraction method allows determining deformation imposed to the sample between two different loading levels, characterizing a precise isodeformation map.…”

Section: Theoretical Considerationsmentioning

confidence: 99%

Determination of Wood Specimens Using Isostrain Patterns Generated for Moiré Technique

Albiero

Rodrigues²,

Beraldo

et al. 2007

Revista Brasileira De Engenharia De Biossistemas

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Brazilian forest's wood characterization requires very complex tasks due to the large number of species available throughout the whole national territory. Available wood characterization methods demand relatively long test timing or they are quite costly and sometimes they exhibit a lack of precision. This research work reports a new method for wood characterization based on a moiré photoelastic technique. Such family of methods is able to generates the microtopography of the object under study and also the stress-strain distribution under a specific loading condition. Moiré means wave like pattern generated when screens of same mesh density are superposed. It is reported the application of a moiré technique in magnifying displacements, being also suitable as a photoelastic method. Three specimens of different wood species were submitted to axial loads before failure meanwhile a grid of specific mesh density was projected onto the object. The experimental setup this work included a digital camera to capture the moiré patterns generated by the projection of a regular grid onto the object and processed by involving software named Gimp and Idrisi. Tests were conducted in the Faculty of Agricultural Engineering at Campinas University, Campinas, SP, Brazil.Keywords: brazilian forest's; interferometry; photoelastic technique; shadow Moiré; isostrain maps; digital pictures. RESUMOA caracterização das madeiras das florestas brasileiras requerem um trabalho muito complexo devido ao grande número de espécies disponíveis em todo o território nacional. Os métodos de caracterização existentes demandam muito tempo e tem custos muito altos além de não terem muita precisão. Esta pesquisa descreve um novo método para caracterização de madeiras baseado na técnica fotoelástica de Moiré. Esta família de metodos são hábeis para gerarem microfotografias do objeto de estudo, assim como de determinarem a distribuição de tensão e formação em objetos a partir de uma carga controlada, isto ocorre devido a padrões de regiões claras e escuras geradas por uma grade sobreposta. A técnica de moiré aumenta os deslocamentos sendo considerado uma técnica fotoelástica. Três amostras de madeiras diferentes foram submetidas a cargas axiais antes da falha enquanto um padrão de difração foi projetado nas amostras. O arranjo experimental foi formado por uma câmera digital para capturar os padrões de moiré gerados, e estas imagens foram processadas pelos softwares Gimp e Idrisi. Os testes foram conduzidos na Faculdade de Engenharia Agrícola da Universidade Estadual de Campinas.Palavras-chaves: florestas brasileiras; interferometria; técnica fotoelástica, Moiré de sombra, mapas de isodeformação.

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High Sensitivity Moiré

Cited by 447 publications

References 0 publications

Research on Subcutaneous Pulse Shape Measurement by Near-infrared Moiré Technique

Research on Subcutaneous Pulse Shape Measurement by Near-infrared Moiré Technique

On the Full-Field Deformation of Single Crystal CuAlNi Shape Memory Alloys—Stress-Induced β₁ → γ'₁ Martensitic Transformation

Determination of Wood Specimens Using Isostrain Patterns Generated for Moiré Technique

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High Sensitivity Moiré

Cited by 447 publications

References 0 publications

Research on Subcutaneous Pulse Shape Measurement by Near-infrared Moiré Technique

Research on Subcutaneous Pulse Shape Measurement by Near-infrared Moiré Technique

On the Full-Field Deformation of Single Crystal CuAlNi Shape Memory Alloys—Stress-Induced β1 → γ'1 Martensitic Transformation

Determination of Wood Specimens Using Isostrain Patterns Generated for Moiré Technique

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On the Full-Field Deformation of Single Crystal CuAlNi Shape Memory Alloys—Stress-Induced β₁ → γ'₁ Martensitic Transformation