• Title/Summary/Keyword: bending loads

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Damage Effects on the Ultimate Strength of Offshore Tubular Members (해양구조물 원통부재의 최종강도에 대한 손상의 영향)

  • Paik, Jeom-Ki;Shin, Byung-Cheon
    • Journal of Ocean Engineering and Technology
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    • v.3 no.2
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    • pp.577-577
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    • 1989
  • In this paper, a detail evaluation of ultimate strength of offshore unstiffened tubular members with bending and local denting damage which are subjected to combined axial force and bending moment and to component load is presented through theoretical and experimental approaches. Based upon the results obtained here, the damage effect on the ultimate strength of tubular member under combined loads and component load is investigated.

Damage Effects on the Ultimate Strength of Offshore Tubular Members (해양구조물 원통부재의 최종강도에 대한 손상의 영향)

  • Paik, Jeom-Ki;Shin, Byung-Cheon
    • Journal of Ocean Engineering and Technology
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    • v.3 no.2
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    • pp.77-86
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    • 1989
  • In this paper, a detail evaluation of ultimate strength of offshore unstiffened tubular members with bending and local denting damage which are subjected to combined axial force and bending moment and to component load is presented through theoretical and experimental approaches. Based upon the results obtained here, the damage effect on the ultimate strength of tubular member under combined loads and component load is investigated.

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Bending of an isotropic non-classical thin rectangular plate

  • Fadodun, Odunayo O.;Akinola, Adegbola P.
    • Structural Engineering and Mechanics
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    • v.61 no.4
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    • pp.437-440
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    • 2017
  • This study investigates the bending of an isotropic thin rectangular plate in finite deformation. Employing hyperelastic material of John's type, a non-classical model which generalizes the famous Kirchhoff's plate equation is obtained. Exact solution for deflection of the plate under sinusoidal loads is obtained. Finally, it is shown that the non-classical plate under consideration can be used as a replacement for Kirchhoff's plate on an elastic foundation.

The Development of Design Formulas for Pipe Loops Used in Large Vessels(II) (대형 선박의 파이프 루프 설계식 개발(II))

  • Park, Chi-Mo;Yang, Park-Dal-Chi;Lee, Jong-Hoon
    • Journal of Ocean Engineering and Technology
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    • v.23 no.1
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    • pp.158-163
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    • 2009
  • Many longitudinal pipes in ships are subject to considerable loads, caused by hull girder bending in the ships and/or thermal loads in some special pipes through which fluids with highly abnormal temperatures are conveyed. As these loads may cause failure in the pipes or their supporting structures, loops have been widely adopted to prevent such failure, based on the idea that they can lower the stress level in a pipe byabsorbing some portion of these loads. But as the loops also have some negative effects, such as causing extra manufacturing cost, deteriorating the function of the pipe, and occupying extra space, the number and dimensions of these loops need to be minimized. This research developed design formulas for pipe loops, modeling them as a spring element, for which the axial stiffness is calculated based on the beam theory, incorporating the flexibility effect of the straight portion of the pipe. The accuracy of the proposed design formulas was verified by comparing two results obtained from the proposed formulas and MSC/NASTRAN. This paper concludes with a sample application of the proposed formulas, showing their efficiency.

Analytical Study in Brake Judder Reduction of Medium Bus (중형 버스의 브레이크 저더 현상 개선에 대한 해석적 고찰)

  • 이계섭;서권희;국종영;천인범
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.148-156
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    • 2001
  • Brake judder, one of low Sequency vibrations in brake system is determined by the excitation of Brake Torque Variation (BTV). The largest contributor to BTV is disc thickness variation. In this study, the static loads of brake torque at Suspension Mounting Points (SW) are obtained by the quasi-static analysis using DADS. The dynamic loads with frequency of BTV at SW are derived from correlation between forced vibration analysis with static loads and brake test results. And the accelerations at steering wheel were analyzed by forced vibration analysis with dynamic loads using commercial finite element program MSC/NASTRAN so that vibration characteristics of vehicle due to brake judder were investigated. Reliability of analysis results was verified through comparing the brake test results. Also, a parametric study with natural frequencies of frame, such as the 1st torsional mode and 1st bending mode, was conducted to reduce vibration amplitudes. As a result we could detect frame natural frequency conditions to improve vibration characteristics and obtained the frame model to reduce vibration amplitude.

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Empirical Relationship Between SP-curves and Tensile Properties in Mn-Mo-Ni Low Alloy Steels (Mn-Mo-Ni 저합금강의 SP-곡선과 인장물성과의 실험적 관계)

  • Lee, Jae-Bong;Kim, Min-Chul;Park, Jai-Hak;Lee, Bong-Sang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.5
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    • pp.554-562
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    • 2004
  • An empirical relationship between parameters from SP curves and tensile properties has been systematically investigated by experimental tests and FEM simulations. A series of SP and tensile tests were performed. SP tests were also simulated by FE analysis with various tensile properties. It was found that the yield loads(Py) and the maximum loads( $P_{MAX}$) in SP curves were linearly related with the yield strength($\sigma$$_{o}$) and the tensile strength($\sigma$$_{UTS}$), respectively. The yield loads defined from the intersection point of two lines tangent to the elastic bending region and plastic bending region showed better relation to the yield strength than those from offset line. The maximum loads in SP curves showing plastic instability region was linearly related with the tensile strengths. The slope of SP curves in simulation results had a close correlation with the hardening coefficient and hardening strength as well.l.l.l.

Analytic responses of slender beams supported by rotationally restrained hinges during support motions

  • Ryu, Jeong Yeon;Kim, Yong-Woo
    • Nuclear Engineering and Technology
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    • v.52 no.12
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    • pp.2939-2948
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    • 2020
  • This paper presents an analytic solution procedure of the rotationally restrained hinged-hinged beam subjected to transverse motions at supports based on EBT (Euler-Bernoulli beam theory). The EBT solutions are compared with the solutions based on TBT (Timoshenko beam theory) for a wide range of the rotational restraint parameter (kL/EI) of slender beams whose slenderness ratio is greater than 100. The comparison shows the followings. The internal loads such as bending moment and shearing force of an extremely thin beam obtained by EBT show a good agreement with those obtained by TBT. But the discrepancy between two solutions of internal loads tends to increase as the slenderness ratio decreases. A careful examination shows that the discrepancy of the internal loads originates from their dynamic components whereas their static components show a little difference between EBT and TBT. This result suggests that TBT should be employed even for slender beams to consider the rotational effect and the shear deformation effect on dynamic components of the internal loads. The influence of the parameter on boundary conditions is examined by manipulating the spring stiffness from zero to a sufficiently large value.

Experimental study on the asymmetric impact loads and hydroelastic responses of a very large container ship

  • Lin, Yuan;Ma, Ning;Gu, Xiechong;Wang, Deyu
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.12 no.1
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    • pp.226-240
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    • 2020
  • This paper presents an experimental investigation of asymmetric impact effects on hydroelastic responses. A 1:64 scaled segmented ship model with U-shape open cross-section backbone was newly designed to meet elastic similarity conditions of vertical, horizontal and torsional stiffness simultaneously. Different wave heading angles and wavelengths were adopted in regular wave test. In head wave condition, parametric rolling phenomena happened along with asymmetric slamming forces, the relationship between them was disclosed at first time. The impact forces on starboard and port sides showed alternating asymmetric periodic changes. In oblique wave condition, nonlinear springing and whipping responses were found. Since slamming phenomena occurred, high-frequency bending moments became an important part in total bending moments and whipping responses were found in small wavelength. The wavelength and head angle are varied to elucidate the relationship of springing/whipping loads and asymmetric impact. The distributions of peaks of horizontal and torsional loads show highly asymmetric property.

A Study on the Bending Strength of a Built-up Beam Fabricated by the $CO_2$ Arc Spot Welding Method ($CO_2$아크 스폿 용접법에 의한 조립보의 굽힘강도에 관한 연구)

  • 한명수;한종만;이준열
    • Journal of Welding and Joining
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    • v.15 no.4
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    • pp.143-153
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    • 1997
  • In this study, bending test was performed on the real-scale, built-up beam test model fabricated by the $CO_2$ arc spot welding to evaluate the applicability of the welding method to the production of the stiffened plate in car-carrying ship. The built-up beam models which were fixed at both ends in longitudinal direction or simply supported to the rigid foundation, depending on the restraint condition of the corresponding car decks considered, were subjected to simulated design vehicle loads or concentrated point loads. During the test, the central deflection and the longitudinal bending stresses were measured from several points on the longitudinal flange face to predict the section properties of the built-up beams. The longitudinal bending stress on each spot weld were also measured to calculate the average horizontal shear force subjected to spot welds. Test results revealed that the shear strength of spot welds with their current weld nugget size and welding pitch was adequate enough to withstand the horizontal shear forces under the design vehicle loads. Although the built-up beam fabricated by the arc spot welding was a discontinuous beam, its mechanical behavior was well explained by the continuous beam theory using the effective breadth of plate. Based on test results, the criterion for the size of spot weld of which the average shear stress might meet the allowable stress requirement of AWS Code could be established.

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Limit Loads for Circular Wall-Thinned Feeder Pipes Subjected to Bending and Internal Pressure. (원형 감육이 발생한 중수로 피더관의 한계하중 평가)

  • Je, Jin-Ho;Lee, Kuk-Hee;Chung, Ha-Joo;Kim, Jong-Sung;Kim, Yun-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.11
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    • pp.1675-1680
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    • 2010
  • Flow Accelerated Corrosion (FAC) occurring during in-service conditions results in localized wall-thinning in the feeder pipes of CANDU. The wall-thinning of the feeder pipes is the main degradation mechanisms affecting the integrity of piping systems. In this paper, we assess the integrity of wall-thinned feeder pipes by limit load analysis. The limit loads for wall-thinning feeder pipes subjected to in-plane bending and internal pressure were determined on the basis of finte element limit analyses. The limit loads are determined from the results of limit analyses of elasticperfectly-plastic materials using the large geometry change. Closed-form approximations of limit load solutions for wall-thinning feeder pipes subjected to in-plane bending and pressure are proposed.