Pulse shaping techniques for a high-g shock tester based on collision principle

Duan, Zhengyong; Tang, Chuansheng; Li, Yang; Junliang, Han; Wu, Guoxiong

doi:10.1063/1.4962710

Cited by 5 publications

(3 citation statements)

References 14 publications

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“…Driven by the technical demands of high-g shock tests and inspired by existing ideas, a compact high-g shock tester with a three-body vertically stacked shock amplifier was developed by the current authors. The experimental results confirmed that this design was successful [25][26][27] . However, a detailed study of the velocity amplification seems to have been deliberately ignored, most likely because the primary focus was on the shock acceleration pulse parameters.…”

supporting

confidence: 66%

Theoretical and experimental study of the “superelastic collision effects” used to excite high-g shock environment

Duan

Zeng

Tang

et al. 2023

Sci Rep

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The excitation technology for high-g-level shock environment experiments is currently a topic of interest, for which velocity amplification by collisions of vertically stacked bodies has been used to develop high-g shock tests with great success. This study investigated the superelastic collision effects generated during high-velocity one-dimensional three-body impacts. Theoretical formulae were derived in brief for an analytical investigation of the collisions. Four experiments were performed with different initial velocities obtained from free-falls from different heights. Velocity gains larger than 5 were obtained for the three-body collisions, and coefficients of restitution larger than 2.5 were observed for the second impact. The experimental results well verified the existence of superelastic collision effects in the one-dimensional three-body impacts.

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supporting

confidence: 66%

Theoretical and experimental study of the “superelastic collision effects” used to excite high-g shock environment

Duan

Zeng

Tang

et al. 2023

Sci Rep

Self Cite

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“…Shown in figure 3(f ) is the normalized total plasma radiated power P rad /P scale . The total radiated power P rad of the plasma including the core and divertor regions is measured by the bolometer diagnostic [24,25]. As the accumulation of lithium in the vessel increases P L−H /P scale decreases significantly, however, no clear difference of P rad /P L-H (~0.1) is observed.…”

Section: Reduced P L-h By LI Wall Conditioningmentioning

confidence: 99%

On the role of the hydrogen concentration in the L-H transition power threshold in EAST

Shao

et al. 2020

Nucl. Fusion

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A decrease in the L-H transition power threshold P L-H under the lithium wall conditioning has been observed since 2010 in EAST. The physical mechanism responsible for the reduced P L-H is found to be related to three phases of wall recycling as determined by the accumulation of lithium in the vessel. In phase I (a few rounds of wall conditioning) the wall recycling is low, while no clear variation of L-H transition power threshold is observed. In phase II (after another few rounds of wall conditioning) a clear increase in the wall recycling is observed, leading to decreased L-H transition power threshold. In phase III the wall recycling is higher and the hydrogen concentration n H / ( n H + n D ) is lower compared to phases I and II. In this third phase the L-H transition power threshold is mainly reduced by the decreased n H / ( n H + n D ) . During phase III of the wall recycling, the quantitative relationship between the hydrogen content and normalized L-H transition power threshold P L-H / P s c a l e is studied for campaigns in 2010, 2012, 2015 and 2016. Data scaling reveals that P L − H / P s c a l e = ( − 1.513 ± 0.135 ) × e ( − 6.989 ± 0.362 ) × n H / ( n H + n D ) + ( 1.698 ± 0.050 ) in the hydrogen concentration range of 3–45%, i.e. P L-H / P s c a l e increases significantly for 3 % < n H / ( n H + n D ) < 20 % , while it increases mildly for 20 % < n H / ( n H + n D ) < 45 % .

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“…e shock properties are controllable and the shock can be repeated within the appropriate accuracy requirements. Shock test machines thus play an important role in simulating the underwater shock explosion environment [6].…”

Section: Introductionmentioning

confidence: 99%

Shock Signal Trend Term Error Correction Method Based on Discrete Wavelet Transform and Low-Frequency Oscillator Combination

Wang

Yan

Zhang³

et al. 2021

Shock and Vibration

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Shock response spectrum (SRS), calculated according to shock loading signal, is the primary metric for assessing the shock resistance ability of shipborne equipment. Nevertheless, the measured shock acceleration signal contains a trend term error that severely distorts the low frequency of the SRS. The accuracy of present correction methods cannot be assured due to a lack of reference. A discrete wavelet transform (DWT) and low-frequency oscillator combination method is proposed for correcting shock signals in this paper. The optimal wavelet parameters can be selected according to a low-frequency spectrum baseline fitted by the measured relative displacement to reject low-frequency trend term errors. Shock machine test results show that the average difference between the low-frequency spectrum baseline and uncorrected SRS is reduced from 89.8% to 3.2%, while the SRS slope rolled off to 5.8 dB/oct after imposing the proposed correction. The corrected SRS can faithfully show the actual shock loading characteristics of shipborne equipment in shock tests.

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Pulse shaping techniques for a high-g shock tester based on collision principle

Cited by 5 publications

References 14 publications

Theoretical and experimental study of the “superelastic collision effects” used to excite high-g shock environment

Theoretical and experimental study of the “superelastic collision effects” used to excite high-g shock environment

On the role of the hydrogen concentration in the L-H transition power threshold in EAST

Shock Signal Trend Term Error Correction Method Based on Discrete Wavelet Transform and Low-Frequency Oscillator Combination

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