نتایج جستجو برای: three dimensional crack

تعداد نتایج: 1546305  

Journal: :The Journal of the Acoustical Society of America 2000
Frazier Hughes O'Brien

In 1976, Hughes and Thompson introduced the idea of steering the maximum response of a linear array by amplitude weighting the output signals of the elements, thus eliminating the need for time delays or phase-shift networks. Currently that amplitude-steered array concept is being extended to a broadband two-dimensional array that can be used for real-time three-dimensional imaging. In shifting...

2015
Tom Baden Andre Maia Chagas Greg Gage Timothy Marzullo Lucia L. Prieto-Godino Thomas Euler

The introduction of affordable, consumer-oriented 3-D printers is a milestone in the current "maker movement," which has been heralded as the next industrial revolution. Combined with free and open sharing of detailed design blueprints and accessible development tools, rapid prototypes of complex products can now be assembled in one's own garage--a game-changer reminiscent of the early days of ...

Journal: :Applied optics 1999
D L Marks R A Stack D J Brady

We show that three-dimensional incoherent primary sources can be reconstructed from finite-aperture Fresnel-zone mutual intensity measurements by means of coordinate and Fourier transformation. The spatial bandpass and impulse response for three-dimensional imaging that result from use of this approach are derived. The transverse and longitudinal resolutions are evaluated as functions of apertu...

Structural health monitoring of cracked structures is one of beloved subject of researchers recently. Consider of crack behavior in the water and energy pipeline is important because of environmental problems. In this paper consider of crack parameters in the underwater pipe subjected to mechanical transient load is investigated. For this purpose, three- dimensional parametric model of cracked ...

Journal: :Adv. Model. and Simul. in Eng. Sciences 2016
H. R. Javani Ron H. J. Peerlings Marc G. D. Geers

A crack initiation and propagation algorithm driven by non-local ductile damage is proposed in a three-dimensional finite strain framework. The evolution of plastic strain and stress triaxiality govern a non-local ductile damage field via constitutive equations. When the damage reaches a critical threshold, a discontinuity in the form of a crack surface is inserted into the three-dimensional co...

2012
Joan Vila-Comamala Yongsheng Pan Jeffrey J. Lombardo William M. Harris Wilson K. S. Chiu Christian David Yuxin Wang

Full-field transmission X-ray microscopy is a unique non-destructive technique for three-dimensional imaging of specimens at the nanometer scale. Here, the use of zone-doubled Fresnel zone plates to achieve a spatial resolution better than 20 nm in the hard X-ray regime (8-10 keV) is reported. By obtaining a tomographic reconstruction of a Ni/YSZ solid-oxide fuel cell, the feasibility of perfor...

Journal: :Optics letters 2014
Kaspar Sakmann Mark Kasevich

Light field microscopy methods together with three-dimensional (3D) deconvolution can be used to obtain single-shot 3D images of atomic clouds. We demonstrate the method using a test setup that extracts 3D images from a fluorescent Rb87 atomic vapor.

Journal: :Optics express 2010
Qian Xu Kebin Shi Haifeng Li Kerkil Choi Ryoichi Horisaki David Brady Demetri Psaltis Zhiwen Liu

We demonstrate a simple approach for inline holographic coherent anti-Stokes Raman scattering (CARS) microscopy, in which a layer of uniform nonlinear medium is placed in front of a specimen to be imaged. The reference wave created by four-wave mixing in the nonlinear medium can interfere with the CARS signal generated in the specimen to result in an inline hologram. We experimentally and theor...

2004
F. P. CHIANG

Three-dimensional deformation field in the vicinity of a blunt crack in a sheet of low-hardening material is determined using laser speckle and moir6 techniques. Experimental results are compared with the HRR singularity field. A zone of dominant three-dimensional effects is mapped out ahead of the crack tip. Strain contours, elastic plastic boundary and maximum shear strain trajectories are al...

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