• Title/Summary/Keyword: impact stresses

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The Effect of Psychobiographical Intensive Interview on Parent's Insight and Parent-Child Relationship Characteristic (심리전기적 심층면담(PII)이 부모의 통찰수준 및 부모-자녀 관계특성에 미치는 효과)

  • Kang, Sang-Hyun;Son, ChongNak
    • Journal of Digital Convergence
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    • v.15 no.5
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    • pp.495-503
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    • 2017
  • The purpose of this study was to investigate the effect of psychobiographical intensive interview(PII) on the parent's insight, parent-child relationship characteristics and counseling session. For this, the PII was conducted to 10 mothers with school age children. PII was semi-structured form that included the intensive interview for exploring psychobiographical information and interpretation counseling of it. The results showed that the level of insight into parent's child problem and relation to parent's own problem was significantly increased. On the other hand, parent-child relationship characteristics (parental efficacy, parenting attitude, and parenting stress) were found to be significant only in some of the parenting stresses. We investigated the possibility as a counseling tool for PII through counseling session impact assessments. As a result of that, we confirmed that there were positive results in task impacts, relationship impacts, and helpful impacts.

Estimation of the Roadbed Settlement and Bearing Capacity According to Radius of Curve and Cant in Railroad (철도의 곡선반경 및 캔트에 따른 노반의 침하 및 지지력 산정)

  • Jeon, Sang-Soo;Eum, Gi-Young;Kim, Jae-Min
    • Journal of the Korean Society of Hazard Mitigation
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    • v.7 no.1 s.24
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    • pp.29-38
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    • 2007
  • The research on the track performance and stability of the tilting-train was performed and the settlement of the roadbed was estimated as the tilting train was being operated on the rail joint under the allowable velocity subjected to the track performance and the stability of the tilting-train. Since the impact on the continuous welded rail (CWR) induced by the tilting-train loading is different from the impact on the rail joint, it needs to investigate the settlement of the roadbed beneath the CWR. In this study, when the tilting-train is being operated on the CWR under the allowable velocity subjected to the track performance and the stability of the tilting-train, the settlement and bearing capacity of the roadbed beneath the CWR have been evaluated using numerical analysis and compared with those beneath the rail joint. The numerical results show that the settlements of the roadbed beneath CWR and rail joint are amount to 71.2% and 88.8% of the allowable settlement, respectively. And the stresses are amount to 10.4% and 12.1% of the allowable bearing capacity, respectively.

Movement and Deposition Characteristics of Debris Flow According to Rheological Factors (유동학적 인자에 따른 토석류의 이동 및 퇴적 특성)

  • Lee, Mi-Ji;Kim, Yun-Tae
    • Journal of the Korean Geotechnical Society
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    • v.29 no.5
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    • pp.19-27
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    • 2013
  • Most of the landslides induced by rainfall in summer rainy season appear in the type of debris flow. Debris flow gives a lot of economic losses and human casualties due to high moving velocity and volume of debris flow. In order to analyze movement and deposition characteristics of debris flow, numerical analysis using FLO-2D program was conducted with various viscosities and yield stresses. As a result of numerical analysis, velocity and runout distance of debris flow decreased as its viscosity increased due to resisting force between particles of debris flow. Consequently, flow depth of debris flow increased and impact force decreased. Yield stress of debris flow affected its initiation and deposition characteristics. As yield stress increased, runout distance of debris flow decreased and its impact force increased. Based on the results of numerical analysis, it was found that velocity of debris flow mainly depended on viscosity, while deposition characteristics (runout distance, deposition width, deposition area) of debris flow depended on both viscosity and yield stress.

Stress Analysis of Tractor Front-End Loader against Impact Load Using Flexible Multi-Body Dynamic Simulation (유연 다물체 동역학 해석을 이용한 충격 하중에 따른 트랙터 프론트 로더의 응력 분석)

  • Shin, Chang-Seop;Kim, Beom-Soo;Han, Hyun-Woo;Chung, Woo-Jin;Cho, Seung-Je;Park, Young-Jun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.3
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    • pp.26-32
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    • 2019
  • This study was conducted to analyze the stresses by impact loads on front-end loaders attached to tractors using flexible multi-body dynamics. The model was designed and validated by comparing previous experimental data with the simulation data obtained in this study. Nine sets of conditions were designed using three weights (500, 300, and 100 kg) loaded inside a bucket and three heights (1700, 1350, and 1000 mm) of the bucket from ground level. A parametric study was carried out at five locations for two types of parts of a front-end loader. All the safety factors for the five locations under all conditions were calculated and were greater than 1. Thus, the designs of the front-end loaders were structurally safe. Based on this study, front-end loaders attached to tractors can be designed effectively in terms of cost and safety.

Stress Analysis of Composite Plate with an Elliptical Hole or a Crack Using Complex Potentials (복소퍼텐셜을 이용한 타원공 또는 균열을 가진 복합재 평판 응력해석)

  • Kwon, Jung-Ho;Hwang, Kyung-Jung
    • Composites Research
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    • v.20 no.5
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    • pp.56-63
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    • 2007
  • An approach using complex potentials is presented for analysis of composite plate with an elliptical hole or a rectilinear crack. Composite structure is susceptible to encounter impact damages, which lead to considerable decrease in its residual strength. Such impact damages could be modeled as an equivalent elliptical hole or notch-like crack. Even though finite element method is widely used to analyze stresses or fracture mechanics parameters around such damage, it is tedious to make successive FE-modeling for damage tolerance assessment under fatigue loadings. In this point of view, the solutions based on complex potentials are very simple and easy to use. The computed results are also compared and discussed with those from FEA.

Impact of Physiological Stresses on Nitric Oxide Formation by Green Alga, Scenedesmus obliquus

  • Mallick, Nirupama;Mohn, Friedrich-Helmuth;Rai, Lalchand;Soeder, Carl-J.
    • Journal of Microbiology and Biotechnology
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    • v.10 no.3
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    • pp.300-306
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    • 2000
  • The rate of apparent nitric oxide (NO) release, as measured in the exhaust gas of green alga, Scenedesmus obliquus, depended on the light intensity and pH. It doubled after lowering the temperature from $25^{\circ}C{\;}to{\;}15^{\circ}C$ and strongly decreased from $35^{\circ}C{\;}to{\;}42^{\circ}C$. The Scenedesmus cells, deficient in nitrogen or phosphorus, demonstrated a significant increase in NO production following their transfer to nitrate- and phosphate-rich media. The addition of herbicides (DCMU and glyphosate) or toxic concentrations of $Cu^{2+}{\;}or{\;}Fe^{3+}$ produced strong NO peaks, resembling those that occurred after sudden darkening. An increase in the $Ni^{2+}$ concentration to 20 ppm resulted in a gradual increase of NO release from the initial ~1.5 ppbv to>20 ppbv, whereas $Cd^{2+}$ instantaneously suppressed the NO by the cultures of Scenedesmus was not altered by L-NNA, an inhibitor of nitric oxide synthase (NOS), or by its substrate, L-arginine. This seems to exclude the role of NOS in the NO formation under study. Accordingly, it can be assumed that the rate of NO formation is mainly a function of dynamic nitrite pool sizes and environmental factors significantly affect the NO production in algae.

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Dynamics of lockstitch sewing process

  • Midha, Vinay Kumar;Mukhopadhyay, A.;Chattopadhyay, R.;Kothari, V.K.
    • The Research Journal of the Costume Culture
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    • v.21 no.6
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    • pp.967-973
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    • 2013
  • During high speed sewing, the needle thread is exposed to dynamic loading, short strike loading, inertia forces, friction, rubbing, force of check spring, bending, pressure, friction, impact, shock and thermal influence. The dynamic thread loading/tension alters throughout the stitch formation cycle and along its passage through the machine. The greatest tensile force occurs at the moment of stitch stretching, when the take up lever pulls for required thread length through the tension regulator. These stresses act on the thread repeatedly and the thread passes 50-80 times through the fabric, the needle eye and the bobbin case mechanism, before getting incorporated into the seam, which result in upto 40% loss in tensile strength of the sewing thread. This damage in the sewing thread adversely affects its processing and functional performance. In this paper, the contribution of dynamic loading, passage through needle and fabric, and bobbin thread interaction in the loss in tensile properties has been studied. It is observed that the loss in tensile properties occurs mainly due to the bobbin thread interaction. Dynamic loading due to the action of take up lever also causes substantial loss in tenacity and breaking elongation of cotton threads.

Static and dynamic load superposition in spacecraft structural analysis

  • Vaquer-Araujo, Xavier;Schottle, Florian;Kommer, Andreas;Konrad, Werner
    • Advances in aircraft and spacecraft science
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    • v.5 no.2
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    • pp.259-275
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    • 2018
  • In mechanical analysis of spacecraft structures situations appear where static and dynamic loads must be considered simultaneously. This could be necessary either by load definition or preloaded structures. The superposition of these environments has an impact on the load and stress distribution of the analysed structures. However, this superposition cannot be done by adding both load contributions directly. As an example, to compute equivalent Von Mises stresses, the phase information must be taken into account in the stress tensor superposition. Finite Element based frequency response solvers do not allow the calculation of superposed static and dynamic responses. A manual combination of loads in a post-processing task is required. In this paper, procedures for static and harmonic loads superposition are presented and supported by analytical and finite element-based examples. The aim of the paper is to provide evidence of the risks of using different superposition techniques. Real application examples such as preloaded mechanism structures and propulsion system tubing assemblies are provided. This study has been performed by the Structural Engineering department of Airbus Defence and Space GmbH Friedrichshafen.

Seismic Influence on Subsea Pipeline Stresses

  • Choi, Byoung-Yeol;Lee, Sang-Gil;Kim, Jin-Kwang;Oh, Jin-Soo
    • Journal of Advanced Research in Ocean Engineering
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    • v.3 no.1
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    • pp.1-14
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    • 2017
  • The safety analysis of an earthquake is carried out during the operation of a subsea pipeline and an onshore pipeline. Several cases are proposed for consideration. In the case of a buried pipeline, permanent ground deformation by the earthquake and an increase of internal pressure by the acceleration of the earthquake should be considered. In the case of a subsea pipeline, a bending moment is caused by liquefaction of the backfill material on a trenched seabed, etc., which results in a high bending moment of the buried pipeline. The bending moment causes the collapse of the subsea pipeline or a leak of crude oil or gas, which results in economic loss due to enormous environmental contamination and social economic loss owing to operation functional failure. Thus, in order to prevent economic loss and operation loss, structurally sensitive design with regard to seismic characteristics must be performed in the buried pipeline in advance, and the negative impact on the buried pipeline must be minimized by conducting a thorough analysis on the seabed and backfilling material selection. Moreover, it is proposed to consider the selection of material properties for the buried pipeline. A more economical review is also required for detailed study.

A Study on Statistical Analysis of Load Carrying Capacity of Steel Bridges (강도로교의 내하력 통계분석과 해석에 관한 연구)

  • Chang, Dong Il;Lee, Hee Hyun;Eom, Yeong Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.1
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    • pp.41-48
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    • 1988
  • Fatigue phenomena usually occur in the structures such as bridges subjected to repeated loading with increasing service year. Especially, applied stresses happen to approach to design values due to rapid increase of traffic volume and vehicle weight, so it gives serious effects to the stability of bridges. Therefore, in this paper, the data for load carrying capacity of bridges obtained from field tests were analysed statistically to investigate bridge behaviour and a basic approach to estimate the impact factor was proposed after a comparison war made between field-test data and the calculated values obtained by using matrix structural analysis method.

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