• Title/Summary/Keyword: 정하중

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Static Load Test for Verification of Structural Robustness of Composite Oxidant Tank for Space Launch Vehicle (우주발사체용 복합재 산화제탱크 구조 강건성 검증을 위한 정하중 시험)

  • Kim, Hyun-gi;Kim, Sungchan
    • Journal of Aerospace System Engineering
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    • v.15 no.5
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    • pp.98-105
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    • 2021
  • This study presented the results of the static load tests conducted to verify the structural robustness of the composite oxidant tank for a space launch vehicle. First, we introduced the test equipment used in the static load test of the composite oxidant tank, and then described the test requirements that the composite oxidant tank must satisfy. In addition, we presented a test set-up diagram consisting of the static load test fixture, hydraulic pressure, control equipment, and data acquisition equipment, and the load profile of the static load test of the composite oxidant tank consisting of shear, equivalent compression, bending, and combination tests. As a result of load control, we verified the reliability of this test by showing the errors between the input load and the feedback load in each channel according to the increase of the test load, and the feedback error between the channel A and channel B of load cell in each load actuator. As a result of the static load test, the load of the actuator was properly controlled within the allowable error range in each test, and we found that the test specimen did not cause damage or buckling that causes significant structural defects in the required load.

Re-distribution of Welding Residual Stress Due to Tensile Pre-load and Its Effects on Fatigue Strength in Padding Plate Weldment (Padding plate 용접구조의 인장 정하중 이력에 의한 용접잔류응력 변화 및 피로강도에의 영향)

  • S.W. Kang;Y.W. Kim;W.S. Kim;D.H. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.38 no.4
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    • pp.75-82
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    • 2001
  • Static loadings on ship structure induced either by water pressure before service such as a tank test and ballasting or by cargo pressure during first laden voyage cause relatively much greater stress than dynamic loadings induced by wave. With these static pre-loadings, the initial residual stresses around welded joint, where fatigue strength is concerned(in most cases, where stress concentration occurs) are expected to be shaken-down in a great extent by the elasto-plastic deformation behavior of material. Therefore, it is more resonable to assess the fatigue strength of ship structure with S-N data which have taken into account the effect of shaken-down residual stresses(re-distributed stresses) on the fatigue strength. In this research work, the re-distribution of residual stresses by the tensile pre-loading is measured using an ordinary sectioning method for specimens of padding plate weldment. Fatigue tests are performed also to evaluate the fatigue strength of the both as-welded and pre-loaded specimens.

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Characteristic of a Soft Ground Behavior Subjected to Static and Dynamic Loads (A Study on the Model Test) (정하중 및 동하중이 작용하는 연약지반의 거동특성(비교모형실험))

  • Kim, Jong-Ryeol;Kang, Jin-Tae;Lee, Chi-Yeal;Part, Yong-Myun;Jeong, Jea-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.24 no.1
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    • pp.111-118
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    • 2008
  • In the study a 2 dimensional model test was executed to grasp the effect of the taking load of equipments on the ground when improving a soft ground like dredging reclaimed ground. The static load and the dynamic load in the consolidated model ground was $0.02kg/cm^2,\;0.03kg/cm^2\;and\;0.04kg/cm^2$ respectively. After consolidating far two months by consolidation load of $0.02kg/cm^2,\;0.03kg/cm^2\;and\;0.04kg/cm^2$ respectively, the ultimate bearing capacity was $0.16kg/cm^2,\;0.19kg/cm^2,\;0.24kg/cm^2$ respectively. And the energy price of dynamic load test at the same point as the settlement of static load test indicated $E=336{\sim}945kg{\cdot}cm,\;E=252{\sim}780kg{\cdot}cm\;and\;E=323{\sim}727kg{\cdot}cm$ for each consolidation load. When the static load and the dynamic load operated at the same ground condition, the heaving quantity was bigger in the case of the dynamic load than in the case of the static load, and the horizontal displacement quantity the in the case of dynamic load was exhibited very deficiently compared to the quantity in the case of static load test.

Shape Optimization of Metal Forming and Forging Products using the Stress Equivalent Static Loads Calculated from a Virtual Model (가상모델로부터 산출된 응력 등가정하중을 이용한 금속 성형품 및 단조품의 형상최적설계)

  • Jang, Hwan-Hak;Jeong, Seong-Beom;Park, Gyung-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.11
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    • pp.1361-1370
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    • 2012
  • A shape optimization is proposed to obtain the desired final shape of forming and forging products in the manufacturing process. The final shape of a forming product depends on the shape parameters of the initial blank shape. The final shape of a forging product depends on the shape parameters of the billet shape. Shape optimization can be used to determine the shape of the blank and billet to obtain the appropriate final forming and forging products. The equivalent static loads method for non linear static response structural optimization (ESLSO) is used to perform metal forming and forging optimization since nonlinear dynamic analysis is required. Stress equivalent static loads (stress ESLs) are newly defined using a virtual model by redefining the value of the material properties. The examples in this paper show that optimization using the stress ESLs is quite useful and the final shapes of a forming and forging products are identical to the desired shapes.

Development of Full-Scale Static Test System for Aircraft Sensor Pod (항공용 센서 포드의 정적 구조시험장비 개발)

  • Jae Myung Cho;Hoon Hyuk Park;Won Woong Lee;Jong In Bae;Han Sol Lee;Eui Hwan Oh
    • Journal of Aerospace System Engineering
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    • v.17 no.1
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    • pp.97-105
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    • 2023
  • For aviation sensor pod, structural integrity should be verified through static structural tests for flight loads induced in various maneuvering conditions of the aircraft. For this, it is necessary to develop a test system for full-scale static load test of sensor pod. Based on test requirements, this paper introduced a test system configuration of the static test and the development of test structure frame, restraints equipment, loading equipment, control, and measurement equipment. In addition, methods and procedures for verifying the developed test system were explained. In conclusion, the static load test and data acquisition were successfully performed. Reliability of the test equipment was also verified in the process.