• Title/Summary/Keyword: Taylor

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Prediction of Impact Fracture for Tungsten Alloy Using the Mohr-Coulomb Fracture Model (Mohr-Coulomb 파단모델을 이용한 텅스텐 합금의 충격 파단 예측)

  • Noh, D.;Fazily, Piemaan;Yu, K.;Lee, S.;Ko, D.K.;Sung, M.J.;Huh, H.;Yoon, J.W.
    • Transactions of Materials Processing
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    • v.30 no.1
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    • pp.16-21
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    • 2021

  • A new concept of ammunition without the use of explosive gunpowder has been recently studied, which achieves performance equal to or higher than that of high explosives. Frangible Armor Piercing (FAP) is one of the concepts, which utilizes a tungsten alloy penetrator specialized for fragmentation. To investigate the fracture behavior of the tungsten alloy penetrator, Taylor impact tests were conducted at various impact velocities. Additionally, finite element analysis was performed to predict the fracture behavior of the tungsten alloy. Compression tests were also carried out at six strain rates for dynamic material properties and the dynamic hardening behavior was successfully predicted with the Lim-Huh model. Finally, the Mohr-Coulomb fracture model based on the mean stress was adopted to predict impact failure in Taylor impact simulation. The analysis predicts the deformation and fracture behaviors of the tungsten alloy successfully.

  • https://doi.org/10.5228/KSTP.2021.30.1.16 인용 PDF KSCI HTML

A Survey on the Mobile Crowdsensing System life cycle: Task Allocation, Data Collection, and Data Aggregation

  • Xia Zhuoyue;Azween Abdullah;S.H. Kok
    • International Journal of Computer Science & Network Security
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    • v.23 no.3
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    • pp.31-48
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    • 2023

  • The popularization of smart devices and subsequent optimization of their sensing capacity has resulted in a novel mobile crowdsensing (MCS) pattern, which employs smart devices as sensing nodes by recruiting users to develop a sensing network for multiple-task performance. This technique has garnered much scholarly interest in terms of sensing range, cost, and integration. The MCS is prevalent in various fields, including environmental monitoring, noise monitoring, and road monitoring. A complete MCS life cycle entails task allocation, data collection, and data aggregation. Regardless, specific drawbacks remain unresolved in this study despite extensive research on this life cycle. This article mainly summarizes single-task, multi-task allocation, and space-time multi-task allocation at the task allocation stage. Meanwhile, the quality, safety, and efficiency of data collection are discussed at the data collection stage. Edge computing, which provides a novel development idea to derive data from the MCS system, is also highlighted. Furthermore, data aggregation security and quality are summarized at the data aggregation stage. The novel development of multi-modal data aggregation is also outlined following the diversity of data obtained from MCS. Overall, this article summarizes the three aspects of the MCS life cycle, analyzes the issues underlying this study, and offers developmental directions for future scholars' reference.

  • https://doi.org/10.22937/IJCSNS.2023.23.3.4 인용 PDF

Dynamic Instability and Multi-step Taylor Series Analysis for Space Truss System under Step Excitation (스텝 하중을 받는 공간 트러스 시스템의 멀티스텝 테일러 급수 해석과 동적 불안정)

  • Lee, Seung-Jae;Shon, Su-Deok
    • Journal of Korean Society of Steel Construction
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    • v.24 no.3
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    • pp.289-299
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    • 2012

  • The goal of this paper is to apply the multi-step Taylor method to a space truss, a non-linear discrete dynamic system, and analyze the non-linear dynamic response and unstable behavior of the structures. The accurate solution based on an analytical approach is needed to deal with the inverse problem, or the dynamic instability of a space truss, because the governing equation has geometrical non-linearity. Therefore, the governing motion equations of the space truss were formulated by considering non-linearity, where an accurate analytical solution could be obtained using the Taylor method. To verify the accuracy of the applied method, an SDOF model was adopted, and the analysis using the Taylor method was compared with the result of the 4th order Runge-Kutta method. Moreover, the dynamic instability and buckling characteristics of the adopted model under step excitation was investigated. The result of the comparison between the two methods of analysis was well matched, and the investigation shows that the dynamic response and the attractors in the phase space can also delineate dynamic snapping under step excitation, and damping affects the displacement of the truss. The analysis shows that dynamic buckling occurs at approximately 77% and 83% of the static buckling in the undamped and damped systems, respectively.

  • https://doi.org/10.7781/kjoss.2012.24.3.289 인용 PDF KSCI