• Title/Summary/Keyword: Maximum principal strain

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Basic Study on Impact Analysis of Automobile (자동차 충돌 해석에 관한 기초 연구)

  • Cho, Jae-Ung;Min, Byung-Sang;Han, Moon-Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.8 no.1
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    • pp.64-70
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    • 2009
  • This study is to analyze the impact of automotive body with computer simulation. The total deformation, equivalent strain and strain and principal stress are analyzed respectively in case of front, rear and side impacts. The maximum total deformation of side impact is more than 6 times as large as that of rear impact. The maximum equivalent strain or stress of side impact is more than 4 times as large as that of rear impact. These deformation, strain and stress of front impact are a little more than those of rear impact. The maximum principal stress of side impact is more than 4.5 times as large as that of rear impact. This stress of front impact is a little more than that of rear impact.

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Comparative Study on the Maximum Principal Strain due to the Hole Spacing and the Detonation Delay Time in the Long-Hole Blasting (장공발파 시 천공간격과 기폭시차에 따른 최대주변형률 비교 연구)

  • Song, Jeong-Un;Park, Hoon;Kim, Seung-Kon
    • Explosives and Blasting
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    • v.32 no.3
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    • pp.10-17
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    • 2014
  • In this study, the effect of the hole spacing and the detonation delay time in the long hole blasting of two free surface rock mass on the variation of the principal strains in the vicinity of blasting holes is investigated by use of the finite element program, Visual FEA. The cross section perpendicular to blasting holes is modelled and the maximum principal strains at some major points in the cracking zone are examined. As a result, it was found that the maximum principal strain in the cracking zone becomes larger in the long hole blasting with the narrower hole spacing and the longer detonation delay time. The maximum principal strain was affected by the detonation position in charge hole.

Comparative Study on the Maximum Principal Strain Due to Detonation Pattern at the Rock Surface (암반 절취면에서 기폭 패턴에 따른 최대주변형률의 비교)

  • Song, Jeong-Un;Park, Hoon;Kim, Seung-Kon
    • Explosives and Blasting
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    • v.35 no.4
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    • pp.10-18
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    • 2017
  • In this study, Rock deformation at the artificially advanced face was investigated by using the finite element code relating to the split blasting conducted in urban area. The maximum principal strain according to the detonation pattern and the detonation delay time at the rock surface was compared with the modeled blast section. As a result, it was found that the maximum principal strain was observed a difference depending on the detonation pattern at the rock surface, and the detonation delay time was an important parameter in split blasting.

Analysis of the Maximum Principal Strain on the Splitting Surface by Blasting Detonation Pattern (발파 기폭 패턴에 따른 분할 단면의 최대주변형률 분석)

  • Song, Jeong-Un;Kim, Seung-Kon;Park, Hoon
    • Explosives and Blasting
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    • v.37 no.2
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    • pp.1-13
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    • 2019
  • In this study, Rock deformation on the splitting surface was investigated by using the finite element code relating to the blasting in urban area. The maximum principal strain according to the blasting detonation pattern was analyzed by the modeled blast section, and deformation of the splitting surface formed by the numerical analysis and the real blasting were compared. As a result, it was found that the maximum principal strain was observed a difference according to the blasting detonation pattern on the splitting surface, and the splitting surface was showed a similar waveform both the numerical analysis and the real blasting.

Distortion and Dilatatioin in the Tensie Failure of Paper

  • Park, Jong-Moon;James L. Thorpe
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.31 no.5
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    • pp.73-85
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    • 1999
  • Yield and fracture are separated in the tensile failure of paper. Failure in the machine direction of photocopy paper is contrasted with failure in the cross-machine direction . The ratios of distortion (shape change) to dilatation (volume change) for individual elements at yield and fracture are described. The ratios of distortion to dilatation are measured and compared to predicted values of the strain energy density theory. To evaluate the effect of the angle from the principal material direction on the strain energy density theory. To evaluate the effect of the angle from the principal material direction on the strain energy density factor, samples are prepared from machine direction to cross-machine direction in 15 degree intervals. the strain energy density of individual elements are obtained by the integration of stress from finite element analysis with elastic plus plastic strain energy density theory. Poison's ratio and the angle from the principal material direction have a great effect ion the ratio fo distortion to dilatation in paper. During the yield condition, distortion prevails over dilatation . At fracture, dilatation is at a maximum.

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On the Crustal Deformation Study Using Permanent GPS Station in Korea Peninsula

  • YUN, Hong-Sic;CHO, Jae-Myoung
    • Korean Journal of Geomatics
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    • v.3 no.2
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    • pp.141-148
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    • 2004
  • This paper deals with the characteristics of strain pattern by using permanent GPS stations in Korea in terms of seismic activity and tectonics. Fourteen GPS stations involved in precise baseline vector solution and horizontal strain components were calculated using the differences of mean baseline from ten deily solutions during the time span of three years. The mean rate of maximum shear strain if 0.12 $\mu$/yr. The mean direction of principal axes of the compression is about $85^{\circ}$ N.

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이중하중을 받는 S45C의 피로거동에 관한 연구

  • 윤두연;이원석;이현우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1992.04a
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    • pp.268-273
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    • 1992
  • Thin walled tubular specimens of 0.45% structural carbon steel were used in the bizxial tests. Biaxial fatigue tosts were conducted on strain control including fully reversed tension-compression and in phase tension torsion loadings. The predictions of the biaxial fatigue life were based upon the uniaxial low cycle fatigue test results. Fatigue lives were ranged from 10$\^$2/to 10$\^$5/cycles. Four multiaxial strain based theories have been developed to correlate biaxial fatigue experimdntal results. These theories showed good correlatins except for maximum shear strain theory. In uniaxial tests, crack behavior was observed that crack initiated in the maximum shear strain direction and propagated in the direction perpendicular to principal stross. But, in biaxial tests, both crack initiation and growth occured on the maximum shear strain direction only.

Investigation of Bottom Cracks in the Carbonated Poly(ethylene terephthalate) Bottle

  • Pae, You-Lee;Nah, Chang-Woon;Lyu, Min-Young
    • Elastomers and Composites
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    • v.38 no.4
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    • pp.354-362
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    • 2003
  • The use of a petaloid design for the bottom of carbonated poly(ethylene terephthalate)(PET) bottles is widely spread. This study investigated the causes of bottom cracks. The tensile yield stress variations of PET according to the crystallinity and stretch ratio were examined, then the stretch ratio and strength in the bottom area of a blown bottle were analyzed. A crack test was also performed to observe the cracking phenomena. The distribution of the effective stress and maximum principal stress were both examined using computer simulation to seek the influence of the bottom design on crack. It was concluded that the bottom cracks occurred because of inadequate material strength due to the insufficient stretching of PET, plus the coarse design of a petaloid bottom. The stretch ratio at the bottom during bottle blowing should be higher than the strain hardening point of PET to produce enhanced mechanical strength. The cracks in the bottom of the PET bottles occurred through crazing below the yield stress. The maximum principal stress was higher in the valleys of the petaloid bottom than in the rest bottom area, and the maximum principal stress had a strong effect on the cracks.

Effects of traffic characteristics on pavement responses at the road intersection

  • Yang, Qun;Dai, Jingwang
    • Structural Engineering and Mechanics
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    • v.47 no.4
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    • pp.531-544
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    • 2013
  • Compared with pavement structures of ordinary road sections, pavement structures in the intersection are exposed to more complex traffic characteristics which may exacerbates pavement distresses such as fatigue-cracking, shoving, shear deformation and rutting. Based on a field survey about traffic characteristics in the intersection conducted in Shanghai China, a three dimensional dynamic finite-element model was developed for evaluating the mechanistic responses in the pavement structures under different traffic characteristics, namely uniform speed, acceleration and deceleration. The results from this study indicated that : (1) traffic characteristics have significant effects on the distributions of the maximum principal strain (MPS) and the maximum shear stress (MSS) at the pavement surface; (2) vehicle acceleration or deceleration substantially impact the MPS and MSS at pavement surface and could increase the magnitude of them by 20 percent to 260 percent; (3) in the vertical direction, with the increase of vehicle deceleration rate, the location of the MPS peak value and the MSS peak value changes from the sub-surface layer to the pavement surface.

The effects of bone density and crestal cortical bone thickness on micromotion and peri-implant bone strain distribution in an immediately loaded implant: a nonlinear finite element analysis

  • Sugiura, Tsutomu;Yamamoto, Kazuhiko;Horita, Satoshi;Murakami, Kazuhiro;Tsutsumi, Sadami;Kirita, Tadaaki
    • Journal of Periodontal and Implant Science
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    • v.46 no.3
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    • pp.152-165
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    • 2016
  • Purpose: This study investigated the effects of bone density and crestal cortical bone thickness at the implant-placement site on micromotion (relative displacement between the implant and bone) and the peri-implant bone strain distribution under immediate-loading conditions. Methods: A three-dimensional finite element model of the posterior mandible with an implant was constructed. Various bone parameters were simulated, including low or high cancellous bone density, low or high crestal cortical bone density, and crestal cortical bone thicknesses ranging from 0.5 to 2.5 mm. Delayed- and immediate-loading conditions were simulated. A buccolingual oblique load of 200 N was applied to the top of the abutment. Results: The maximum extent of micromotion was approximately $100{\mu}m$ in the low-density cancellous bone models, whereas it was under $30{\mu}m$ in the high-density cancellous bone models. Crestal cortical bone thickness significantly affected the maximum micromotion in the low-density cancellous bone models. The minimum principal strain in the peri-implant cortical bone was affected by the density of the crestal cortical bone and cancellous bone to the same degree for both delayed and immediate loading. In the low-density cancellous bone models under immediate loading, the minimum principal strain in the peri-implant cortical bone decreased with an increase in crestal cortical bone thickness. Conclusions: Cancellous bone density may be a critical factor for avoiding excessive micromotion in immediately loaded implants. Crestal cortical bone thickness significantly affected the maximum extent of micromotion and peri-implant bone strain in simulations of low-density cancellous bone under immediate loading.