A Study on the Effects of Specimen Geometry on Measurement Accuracy of Dynamic Constitutive Properties of Metals Using SHTB

Nguyen, Khac-Ha; Lee, Chang-Whan; Shin, Hyunho; Lee, Joo Hyoung; Kim, Jong-Bong

doi:10.1007/s12541-020-00368-y

Cited by 4 publications

(2 citation statements)

References 24 publications

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“…At the same time, the transmission wave signal was weak, the strain rate and strain had to be calculated using the incident wave signal, meanwhile the stress–strain relationship was derived by converting the transmission voltage into force 11 . The engineering stress–strain relation of specimens can be determined by using one‐dimensional stress wave theory 12–14 :

\overset{ε}{true} ((), t) goodbreak= 2 C_{0} \frac{ε_{I}}{L_{s}},

ε ((), t) goodbreak= 2 C_{0} \int_{0}^{t} \frac{ε_{I}}{L_{s}} italicdt,

σ ((), t) goodbreak= \frac{F}{A_{s}},

where

C_{0}

is the sound wave velocity of bars, which is calculated by

\sqrt{\frac{E}{ρ}}

(

E

is the Young's modulus while ρ is density of bars).

L_{s}

is the initial length of the specimen,

ε_{I}

is the incident wave recorded by strain gauges glued at the center of the incident bar,

F

is the load converted from the incident voltage,

A_{s}

is the cross‐sectional area the specimen.…”

Section: Methodsmentioning

confidence: 99%

“…At the same time, the transmission wave signal was weak, the strain rate and strain had to be calculated using the incident wave signal, meanwhile the stress-strain relationship was derived by converting the transmission voltage into force. 11 The engineering stress-strain relation of specimens can be determined by using one-dimensional stress wave theory [12][13][14] :…”

Section: High Strain Rates Tensile Testsmentioning

confidence: 99%

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Tensile properties of flexible carbon nanotube film/PVA composite at various strain rates

Lyu

Wang

et al. 2023

Polymer Composites

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The quasi‐static tensile properties of carbon nanotube (CNT) composites have already been extensively studied, while their impact tensile properties under high rates have rarely been investigated. In this work, CNT film/PVA composites were prepared by impregnation and hot press curing, whereas CNT films were prepared by floating catalyst chemical vapor deposition (FCCVD). Instron 3365 and the miniaturized split Hopkinson tensile bar (SHTB) were used for tensile tests at various strain rates. The results show that the tensile properties of PVA‐impregnated CNT film are significantly improved, and the strain rate effect is remarkable. The tensile properties are best when the mass fraction of PVA is 1.5%. At a low strain rate of 0.001 s−1, the maximum stress and energy absorption (EA) of CNT composites are 502.5 MPa and 63.6 MJ/m3, respectively. And at the high strain rate of 3100 s−1, the maximum stress and EA of CNT composites are 969.0 MPa and 166.4 MJ/m3, respectively. Scanning electron microscopy (SEM) was used to observe the failure morphologies at tensile fracture of composites under different strain rates. At low strain rate, the failure mode is the pulling fracture of tube bundles and the crushing of polymers, while at high strain rate is the folding and spring back of tube bundles, as well as the debonding of polymers.

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