• Title/Summary/Keyword: Impact strain analysis

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Impact characteristics of the stainless sheet on the fixed boundary condition (고정형 조건에서의 스테인레스 강판의 충격 특성)

  • Ahn, Dong-Gyu;Moon, Kyung-Je;Jung, Chang-Gyun;Han, Gil-Young;Yang, Dong-Yol
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.48-53
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    • 2007
  • The objective of this paper is to investigate the influence of impact conditions on the impact characteristics of the stainless sheet for the case of the fixed boundary conditions. In order to examine impact characteristics of the sheet, three-dimensional finite element analyses and impact tests have been performed. High speed tensile tests have been carried out to obtain strain-stress relationships including the effects of the strain rate. In order to improve an accuracy of the FE analysis, the hyper-elastic model and the damping factor have been introduced. The results of the FE analyses and the impact tests have been shown that the diameter of the impact head does not affect the absorption energy of the stainless sheet. In addition, it has been shown that the absorption rate of energy maintains almost $82.5\;\sim\;83.5\;%$ irrespective of the impact energy level and the diameter of the impact head. From the results of FE analyses, the variation of stress and strain energy in the stainless sheet has been quantitatively examined.

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Strain rate effect of steel-concrete composite panel indented by a hemispherical rigid body

  • Zhao, Weiyi;Wang, Lin;Yang, Guotao;Wang, Ziguo;Gao, Zepeng;Guo, Quanquan
    • Steel and Composite Structures
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    • v.36 no.6
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    • pp.703-710
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    • 2020
  • This paper presents numerical and theoretical investigations on the strain rate in steel-concrete composite (SC) panels under low-velocity impact of a hemispherical rigid body. Finite element analyses were performed on five specimens with different loading rates. The impact energy was kept constant to eliminate its influence by simultaneously altering the velocity and mass of the projectile. Results show that the strain rate in most parts of the specimens was low and its influence on bearing capacity and energy dissipation was limited in an average sense of space and time. Therefore, the strain rate effect can be ignored for the analyses of global deformation. However, the strain rate effect should be considered in local contact problems. Equations of the local strain and strain rate were theoretically derived.

Evaluation of Dynamic Deformation Behaviors in Metallic Materials under High Strain-Rates Using Taylor Bar Impact Test (Taylor 봉 충격시험을 통한 고 변형률속도하 금속재료의 동적변형거동 평가)

  • Bae, Kyung Oh;Shin, Hyung Seop
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.9
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    • pp.791-799
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    • 2016
  • To ensure the reliability and safety of various mechanical systems in accordance with their high-speed usage, it is necessary to evaluate the dynamic deformation behavior of structural materials under impact load. However, it is not easy to understand the dynamic deformation behavior of the structural materials using experimental methods in the high strain-rate range exceeding $10^4\;s^{-1}$. In this study, the Taylor bar impact test was conducted to investigate the dynamic deformation behavior of metallic materials in the high strain-rate region, using a high-speed photography system. Numerical analysis of the Taylor bar impact test was performed using AUTODYN S/W. The results of the analysis were compared with the experimental results, and the material behavior in the high strain-rate region was discussed.

A Study on the Delamination Growth in Composite Laminates Subjected to Low-Velocity Impact (저속 충격을 받는 복합 재료 적층판의 층간 분리 성장에 관한 연구)

  • 장창두;송하철;김호경;허기선;정종진
    • Journal of Ocean Engineering and Technology
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    • v.16 no.6
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    • pp.55-59
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    • 2002
  • Delamination means that cracking occurs on the interface layer between composite laminates. In this paper, to predict the delamination growth in composite laminates subjected to low-velocity impact, the unit load method was introduced, and an eighteen-node 3-D finite element analysis, based on assumed strain mixed formulation, was conducted. Strain energy release rate, necessary to determine the delamination growth, was calculated by using the virtual crack closure technique. The unit load method saves the computation time more than the re-meshing method. The virtual crack closure technique enables the strain energy release rate to be easily calculated, because information of the singular stress field near the crack tip is not required. Hence, the delamination growth in composite laminates that are subjected to low-velocity impact can be efficiently predicted using the above-mentioned methods.

Dvnarnic Reswnse of Laminated Com~osite Shell under Low-Velocity Impact (복합적층쉘의 저속충격에 대한 동적 거동 해석)

  • 조종두;조영훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.969-974
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    • 1994
  • The dynamic behavior of graphite/epoxy laminated composite shell structure due to low-velocity impact is investigated using the finite element method. In this analysis, the Newmark's constant-acceleration time integration algorithm is used. The impact response such as contact force, central deflection and dynamic strain history form shell structure analysis are compared with those form the plate non-linear analysis. The effects of curvature, impact velocity and mass of impactor on the composite shell are discussed.

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Lab-scale impact test to investigate the pipe-soil interaction and comparative study to evaluate structural responses

  • Ryu, Dong-Man;Lee, Chi-Seung;Choi, Kwang-Ho;Koo, Bon-Yong;Song, Joon-Kyu;Kim, Myung-Hyun;Lee, Jae-Myung
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.4
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    • pp.720-738
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    • 2015
  • This study examined the dynamic response of a subsea pipeline under an impact load to determine the effect of the seabed soil. A laboratory-scale soil-based pipeline impact test was carried out to investigate the pipeline deformation/strain as well as the interaction with the soil-pipeline. In addition, an impact test was simulated using the finite element technique, and the calculated strain was compared with the experimental results. During the simulation, the pipeline was described based on an elasto-plastic analysis, and the soil was modeled using the Mohr-Coulomb failure criterion. The results obtained were compared with ASME D31.8, and the differences between the analysis results and the rules were specifically investigated. Modified ASME formulae were proposed to calculate the precise structural behavior of a subsea pipeline under an impact load when considering sand- and clay-based seabed soils.

Low-Velocity Impact Response Analysis of Composite Laminates Considering Higher Order Shear Deformation and Large Deflection (고차전단변형과 대처짐을 고려한 복합적층판의 저속충격거동 해석)

  • 최익현;홍창선
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.12
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    • pp.2982-2994
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    • 1993
  • Low-velocity impact responses of composite laminates are investigated using the finite element method based on various theories. In two-dimensional nonlinear analysis, a displacement field considering higher order shear deformation and large deflection of the laminate is assumed and a finite element formulation is developed using a C$^{o}$-continuous 9-node plate element. Also, three-dimensional linear analysis based on the infinitesimal strain-displacement assumptions is performed using 8-node brick elements with incompatible modes. A modified Hertzian contact law is incorporated into the finite element program to evaluate the impact force. In the time integration, the Newmark constant acceleration algorithm is used in conjuction with successive iterations within each time step. Numerical results from static analysis as well as the impact response analysis are presented including impact force histories, deflections, strains in the laminate. Impact responses according to two typical low-velocity impact conditions are compared each other.

An Experimental Study on the Impact Force of a Mechanical HeBrt Valve Prostheses (기계식 심장판막의 충격력에 관한 실험적 연구)

  • 이정한;천길정
    • Journal of Biomedical Engineering Research
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    • v.17 no.2
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    • pp.215-220
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    • 1996
  • Impact force and strains induced by impact between the occluder and the struts have been measured with force sensor and strain gages. The maximum reaction force was about 25N, and the calculated impact force on the root of the struts amount about 9-17W. Impact force on the inlet strut is greater than that of the outlet strut, but the strain on the outlet strut is much higher than that of the inlet strut. These values might cause severe damage on the valve in the critical cases. The results of this study may be extended for the analysis of the endurance limit and optimal design of the struts and occluder.

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Dynamic Material Property of Mn-B Alloy High-Strength Steel (Mn-B 합금계 고강도 강의 동적 물성)

  • Choi, Chang;Hong, Sungin
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.11
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    • pp.124-131
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    • 1996
  • The dynamic material property of Mn-B ally high-strength steel is investigated through the rod impact test which is one of simple test methods for the analysis of the material behavior under high-strain-rate. Rod impact test is performed to produce the deformed shape of rod and analyzed by the one-dimensional theory based on conservation law and the two-dimensional hydrocode AUTODYN-2D. The dynamic yield stress is determined and compared with the static yield stress to investigate the strain-rate sensitivity of Mn-B alloy high-strength steel.

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Development of an Impact Force Measurement Device with an Attached Strain Gauge (스트레인게이지가 부착된 충격력 측정 장비 개발)

  • Jeong, Ik-Su
    • Korean Journal of Applied Biomechanics
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    • v.22 no.2
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    • pp.243-251
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    • 2012
  • The purpose of this study was to develop an impact force measurement device in order to facilitate the acquisition of quantitative data for the analysis of various sporting events. The device was designed to include cylindrical aluminum supports of 220 mm diameter, which allows mounting and dismounting of the device on walls and frames. In addition, a hard sponge for impact absorption, as well as 4 springs, were attached to the plate. Both were attached to prevent psychological variables and injuries. When a subject applies force on the device, accurate data about the maximum repulsive force is acquired in real time, with a lag of only 0.001 s. The device was calibrated in four steps: (1) increase, (2) increase, (3) increase-decrease, and (4) increase-decrease. The maximum relative expanded uncertainty was 0.166%, indicating that the impact force measurement was sufficiently reliable. The proposed device can be applied to various sporting situations and is expected to be useful for studying kinetics.