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2018 IEEE Far East NDT New technology and Application Forum, FENDT 2018

作者： Gan, Yong Chen, Guo Lu, Chao Chen, Yao Key Laboratory of Non-destructive Testing Technology Nanchang Hangkong University Nanchang330063 China State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing100190 China

ISBN: (纸本)9781538662304

When the components with arbitrarily shaped are detected by the ultrasonic imaging test, the coupling medium such as immersion or wedge is unavoidable used for ensuring the coupling condition. In this state ultrasonic wave will propagate in the arbitrarily shaped two-media interface between coupling medium and component. For the traditional ultrasonic imaging method which the sound velocity is considered constant, the above condition would cause the wrong position of defects in the image. To overcome the problem, a method combining virtual source (VS) and synthetic aperture focusing technique (SAFT) was applied. Firstly, the sound propagation time of the first interface echo of each elements were measured. Then a series of virtual sources at the two-media interface were created by the time of flight (TOF) of two consecutive elements. Secondly, in virtue of the virtual sources, the two-segment sound propagation path from emitting elements to virtual sources and from here to focus points were respectively calculated. Last each point of the imaging region was focused by the delay and sum process of SAFT. The result showed the defect location of component were displayed accurately in the VS-SAFT image. © 2018 IEEE.

关键词： Ultrasonic imaging

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Material point methods applied to granular compaction

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AIP Conference Proceedings 2024年第1期3066卷

作者： Paul L. Barclay Michelle A. Espy Brian M. Patterson David Alexander Christina Hanson Caitlin Woznick Duan Z. Zhang Larry G. Hill Fluid Dynamics & Solid Mechanics Theoretical Division Los Alamos National Laboratory MS-B216 PO Box 1663 Los Alamos NM 87545 USA Non-Destructive Testing & Evaluation Engineering Technology and Design Los Alamos National Laboratory MS-P915 PO Box 1663 Los Alamos NM 87545 USA Engineered Materials Materials Science and Technology Los Alamos National Laboratory MS-E549 PO Box 1663 Los Alamos NM 87545 USA High Explosive Science & Technology Weapon Stockpile Modernization Los Alamos National Laboratory MS-C920 PO Box 1663 Los Alamos NM 87545 USA

The dual domain material point (DDMP) method, an extension of the material point method, is applied to investigate compaction and crushing of sugar pearls and rock sugar crystals undergoing large deformation and failure. DDMP is chosen because of its capability to simulate complex geometry and to avoid mesh tangling that is often encountered in finite element methods. Numerical results of the compaction and breakup of individual sugar pearls, multiple of sugar pearls, and multiple rock sugar crystals are compared with experimental results. The compaction of multiple rock sugar crystals introduces a pre-processing challenge due to the complex initial geometry. To address this challenge, a fast method is introduced to generate initial material point locations given a stereolithography (STL) file. The method is scalable to generate billions of material points using a single processor in a feasible time frame.

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Improved Composite nonlinear Feedback Control for Robot Manipulators

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Journal of Donghua University(English Edition) 2018年第6期35卷 464-468页

作者： GONG chenglong JIANG Yuan LU Ke College of Information Engineering Nanchang Hangkong University School of Engineering Management and Information Technology University of Chinese Academy of Sciences Non-destructive Testing Technology Ministry of Education Key Laboratory Nanchang Hangkong University

External disturbances or inaccurate mathematical model built will inevitably impose a disadvantageous effect on the robot system,which generates positioning errors,vibrations,as well as weakening control performances of the system. The strategy of combining adaptive radial basis function( RBF) neural network control and composite nonlinear feedback( CNF) control is studied,and a robot CNF controller based on RBF neural network compensation is proposed. The core is to use RBF neural network control to approach the uncertainty of the system online,as the compensation term of the CNF controller,and make full use of the advantages of the two control methods to reduce the influence of uncertain factors on the performance of the system. The convergence of closed-loop system is proved. Simulation results demonstrate the effectiveness of this strategy.

关键词： robot uncertainty composite nonlinear feedback (CNF) adaptive RBF neural network system convergence trajecfory tracking

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Dual-wavelength mid-infrared generation using intracavity stimulated raman scattering of PPLN

IEEE Photonics Journal

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IEEE Photonics Journal 2018年第6期10卷 1-8页

作者： Wang, Peng Cheng, Xi Li, Xiao Xu, Xiaojun Han, Kai Chen, Jian College of Advanced Interdisciplinary Studies National University of Defense Technology Changsha410073 China Anhui Province Key Laboratory of Non-Destructive Evaluation ZC Optoelectronic Technologies Ltd. Hefei230000 China

We report, to the best of our knowledge, the first demonstration of a continuous-wave, dual-wavelength (DW) mid-infrared optical parametric oscillator (OPO) based on the stimulated Raman scattering (SRS) effect of periodically poled lithium niobate (PPLN). The OPO was pumped by two independent fiber lasers, one being fixed at 1018 nm and the other being tunable. The high-power 1018-nm source built parametric oscillation, induced SRS effect in PPLN and generated 1495-nm signal beam as well as 1506-nm Raman beam. The tunable fiber laser was set at 1080 nm and the phase-matched difference frequency generation (DFG) occurred between the 1506-nm Raman beam and 1080-nm pump beam. Finally, DW idler beam located at 3189 and 3819 nm was obtained whose power ranged from 8.044 to 8.115 W, in which the 3189-nm idler power made up the majority of about 8 W and the maximum 3819-nm idler power reached 0.154 W. The slope and conversion efficiency of DFG and OPO processes was also discussed separately. © 2018 IEEE.

关键词： Infrared devices

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Full-scale testing of an ultrasonic guided wave based structural health monitoring system for a thermoplastic composite aircraft primary structure 9

Full-scale testing of an ultrasonic guided wave based struct...

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9th European Workshop on Structural Health Monitoring, EWSHM 2018

作者： Ochôa, Pedro Groves, Roger M. Benedictus, Rinze Structural Integrity and Composites Group Faculty of Aerospace Engineering Delft University of Technology Netherlands Aerospace Non-Destructive Testing Laboratory Faculty of Aerospace Engineering Delft University of Technology Netherlands

This paper describes the test campaign of an ultrasonic guided wave (GW) based structural health monitoring system (SHM) deployed on a full-scale stiffened panel of a thermoplastic composite horizontal stabilizer torsion box. The diagnostic capabilities of the SHM system were successfully evaluated by testing barely-visible impact damage of different severities, applied in different critical areas of the structure. The test campaign allowed the successful validation of a novel procedure to consistently and reliably design a piezoelectric transducer network. It also allowed the gathering of strong evidence that piezoelectric transducer technology has appropriate durability characteristics for real SHM applications. Finally, it enabled the study of the influence of audible structural vibrations on GW signals. © 2018 ***. All rights reserved.

关键词： Structural health monitoring

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Research on Ultrasonic Imaging for Arbitrarily Shaped Interface Based on Virtual Source

Research on Ultrasonic Imaging for Arbitrarily Shaped Interf...

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Far East Forum on nondestructive Evaluation/testing: New technology & Application (FENDT)

作者： Yong GAN Guo CHEN Chao LU Yao CHEN Key Laboratory of Non-destructive Testing Technology Nanchang Hangkong University Nanchang China

ISBN: (纸本)9781538662311;9781538662304

关键词： Acoustics Ultrasonic imaging Apertures Phased arrays Focusing Aluminum

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Fragmentation and scaling behavior of rock sugar crystals as a surrogate for high explosive crushing

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AIP Conference Proceedings 2024年第1期3066卷

作者： Michelle Espy David Alexander Paul Barclay Christina Hanson Scott Linnell Brian Patterson Theresa Quintana Andre Spears Caitlin Woznick Duan Zhang Larry Hill E-6: Non-Destructive Testing & Evaluation Los Alamos National Laboratory MS-P915 P.O. Box 1663 Los Alamos NM 87545-0001 USA T-3: Fluid Dynamics and Solid Mechanics Los Alamos National Laboratory MS-B216 P.O. Box 1663 Los Alamos NM 87545-0001 USA Q-5: High Explosives Science and Technology Los Alamos National Laboratory MS-C920 P.O. Box 1663 Los Alamos NM 87545-0001 USA MST-7: Engineered Materials Los Alamos National Laboratory MS-E549 P.O. Box 1663 Los Alamos NM 87545-0001 USA

The detonation properties of plastic-bonded explosives (PBXs) depend on both the bulk void fraction, and the way voids are distributed. The latter depends on how high explosive (HE) crystals crush and, for a PBX, how the binder flows. Thus, to engineer void structure in pressed pieces, one must understand the complex transformation that occurs during the pressing process. Most explosives are brittle and closely resemble sucrose in their mechanical properties. For this reason, table sugar has often been used as a mechanical mock. Here we crush a good-quality rock sugar and diagnose the resulting structures via micro-Computed-Tomography (CT). A 4 - 6 mm grain size is used to enable study of crushing over many generations before spatial resolution is compromised. About 10 grains are crushed, in nine discrete increments, in a test cell optimized for the purpose. CT scans at a resolution of 10 µm are performed following each increment, on material that is stationary in the frame of the cell. Rock sugar is also pressed in a traditional die-punch setup to similar levels of compaction and the resulting volume-weighted particle size distribution (PSD) measured to test the hypothesis that the resulting PSD would develop towards a fractal distribution. A fractal PSD would be expected as sucrose (and HE) are brittle crystals and should fracture to optimally fill space, as in the Apollonian sphere packing problem with a fractal dimension 2.47. Our results show that a regime of crushing consistent with a fractal dimension of 2.61 develops. A second regime of non-fractal behavior for larger particles, is also observed. In addition to observation of these qualitative features; the measured structures were passed to a CartaBlanca++ code, which implements the dual domain material point (DDMP) method, to quantitatively compare experiments and computations in order to understand what type of constitutive models produce the most realistic crushing behavior. In this paper we present the

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Structural, magnetic properties, and electronic structure of hexagonal FeCoSn compound

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Chinese Physics B 2018年第2期27卷 476-481页

作者：李勇代学芳刘国栋魏志阳刘恩克韩小磊杜志伟郗学奎王文洪吴光恒 School of Material Science and Engineering Hebei University of Technology State Key Laboratory for Magnetism Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences National Analysis and Testing Center for Nonferrous Metals & Electronic Materials Beijing General Research Institute for Non-ferrous Metals

The structural, magnetic properties, and electronic structures of hexagonal Fe Co Sn compounds with as-annealed bulk and ribbon states were investigated by x-ray powder diffraction（XRD）, differential scanning calorimetry（DSC）, transmission electron microscope（TEM）, scanning electron microscope（SEM）, magnetic measurements, and first-principles calculations. Results indicate that both states of FeCoSn show an Ni_2In-type hexagonal structure with a small amount of FeCo-rich secondary phase. The Curie temperatures are located at 257 K and 229 K, respectively. The corresponding magnetizations are 2.57 μB/f.u. and 2.94 μB/f.u. at 5 K with a field of 50 kOe（1 Oe = 79.5775 A·m^（-1））. The orbital hybridizations between 3 d elements are analyzed from the distribution of density of states（DOS）, showing that Fe atoms carry the main magnetic moments and determine the electronic structure around Fermi level. A peak of DOS at Fermi level accounts for the presence of the FeCo-rich secondary phase. The Ni_2In-type hexagonal FeCoSn compound can be used during the isostructural alloying for tuning phase transitions.

关键词： FeCoSn hexagonal structure first-principles calculations

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Damage evaluation based on ultrasonic testing of compos-ite aircraft elements and image analysis methods

Damage evaluation based on ultrasonic testing of compos-ite ...

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2018 International Mechanical and Industrial Engineering Conference, IMIEC 2018

作者： Wronkowicz, Angelika Dragan, Krzysztof Silesian University of Technology Institute of Fundamentals of Machinery Design Konarskiego 18A Gliwice44-100 Poland Air Force Institute of Technology Laboratory of Non-Destructive Testing 6 Ks. Boleslawa Warsaw01-494 Poland

Composite aircraft elements are inspected with the use of non-destructive testing methods to detect the damage appearance and monitor its progression. Ultrasonic testing is one of the most commonly applied methods owing to its capabilities of detecting various types of internal flaws and dam-age as well as evaluating their location and geometrical properties. There are several di culties in analysing the ultrasonic data, which cover the high time-consumption of such analyses resulting from large sizes of the scans and a man-ual handling of them. Thus, due to the possible occurrence of human errors, there is a necessity of increasing the e ciency of these inspections by aiding the analysis of the ultrasonic data. The paper presents proposed methods of the application of image analysis methods for supporting the procedures of the ul-trasonic evaluation of the aircraft structures. These cover facilitating the steps of damage detection, quantification as well as a three dimensional reconstruc-tion and visualisation. The proposed approaches are computationally e cient and may facilitate the data interpretation and damage evaluation procedures. © The Authors, published by EDP Sciences, 2018.

关键词： Damage detection

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Solving problems in geomechanics: Comparison of the fidesys strength analysis system and the plaxis software package

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key Engineering Materials 2017年第1期755卷 328-332页

作者： Sas, Ivan E. Cherepetskaya, Elena B. Pavlov, Ilya A. National University of Science and Technology MISiS Laser Ultrasonic Non-Destructive Testing Laboratory Moscow Russia

This article is devoted to solving problems with known theoretical solutions in the Fidesys software package. Within the framework of the work, modeling of a biaxial shear test of the ground and simulating a draft of a flexible foundation was done. The solutions obtained were correlated with the solutions of such problems in the Plaxis software package. According to the results of the study, it can be concluded that the Fidesys software complex allows solving problems in the field of geomechanics. At the same time, it is not inferior to recognized solutions in terms of functionality. © 2017 Trans Tech Publications, Switzerland.

关键词： Finite element method

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