• Title/Summary/Keyword: Bending resistance

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Ultimate Strength Interaction of Steel/Concrete Composite Trapezoidal Box Girders Subjected to Concurrent Action of Bending and Torsion (휨과 비틀림을 동시에 받는 강/콘크리트 합성 제형 박스거더의 극한강도 상호작용)

  • Kim, Kyung-Sik
    • Journal of Korean Society of Steel Construction
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    • v.22 no.5
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    • pp.465-475
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    • 2010
  • In the horizontally curved bridges, girders are subjected to the combined action of vertical bending and torsion due to their curvatures without any eccentric loads. As subjected to bending and torsion, the ultimate strength of steel/concrete composite box girders are limited by the diagonal tensile stress in the deck concrete induced by the St. Venant torsion. To determine the ultimate strength of composite box girders in bending and torsion and their interactions, this study conducted a 3-dimensional FEA and classical strength of materials investigation. Using ABAQUS, the FEA fully utilized advanced nonlinear analysis techniques simulating material/geometrical nonlinearity and post-cracking behaviors. The ultimate strength from numerical data were compared with theoretically derived values. Concurrent compressive stresses in the concrete deck improve the shear-resisting capacity of concrete, thereby resulting in an increased torsional resistance of the composite box girder in positive bending. The proposed interaction equation is very simple yet it provides a rational lower bound in determining the ultimate strength of concrete/steel composite box girders.

Analysis of end-plate connections at elevated temperatures

  • Lin, Shuyuan;Huang, Zhaohui;Fan, Mizi
    • Steel and Composite Structures
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    • v.15 no.1
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    • pp.81-101
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    • 2013
  • In this paper a robust 2-noded connection element has been developed for modelling the bolted end-plate connection between steel beam and column at elevated temperatures. The numerical procedure described is based on the model proposed by Huang (2011), incorporating additional developments to more precisely determinate the tension, compression and bending moment capacities of end-plate connection in fire. The proper failure criteria are proposed to calculate the tension capacity for each individual bolt row. In this new model the connection failure due to bending, axial tension, compression and shear are considered. The influence of the axial force of the connected beam on the connection is also taken into account. This new model has the advantages of both the simple and component-based models. In order to validate the model a total of 22 tests are used. It is evident that this new connection model has ability to accurately predict the behaviour of the end-plate connection at elevated temperatures, and can be used to represent the end-plate connections in supporting performance-based fire resistance design of steel-framed composite buildings.

Computer-Aided Design of Involute Cylindrical Gears for Power Transmission (컴퓨터를 이용한 동력전달용 인벌류우트 원통치차의 설계)

  • 정태형;김민수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.3
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    • pp.594-602
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    • 1990
  • A computer-aided design system of involute cylindrical gears(spur and helical gears) for power transmission is developed, in which the volume of a gear unit is minimized with satisfying various design constraints. As the design constraints, bending strength and pitting resistance of AGMA 218.01, scoring of Dudley's flash temperature, contact ratio, and involute interference of pinion are considered and effective factors for strength calculation(life, reliability, hardness ratio, load distribution, velocity, etc.) are also included. This complicated nonlinear optimization problem is solved by using ALM(Augmented-Lagrange-Multiplier) method with self scaling BFGS(Broydon-Fletcher-Goldfarb-Shanno) method employed for unconstrained optimization programming. This design method can be easily applied to designing power transmission gear unit in the machines of various kinds. It is expected for the proposed method to be a contribution for an automated design of gear unit towards weight minimization, miniaturization and high strength of gear unit.

Synthesis of Silicone Softner for Permanent Press Finish and Its Characterization (Permanent Press 가공용 실리콘 유연제의 합성과 그의 특성화)

  • Park, Chang-Hwan;Kim, Seung-Jin;Kim, Young-Geun;Park, Hong-Soo
    • Journal of the Korean Applied Science and Technology
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    • v.12 no.1
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    • pp.29-34
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    • 1995
  • Silicone softner(SSN-3) for permanent press(PP) finish was prepared by blending beef tallow hardened oil for Improving softness, water, the emulsion, which was synthesized from pentaerythritol monostearate as a softening component and silicone oil KF-96 as a lubricating component. The prepared SSN-3 and the PP finishing resin were applied to PP finishing cotton broad cloth and P/C gingham samples using one bath method. The properties such as crease recovery, tear strength, bending resistance test were tested. The samples treated with SSN-3 and PP finishing resin have improved properties, compared with nontreated samples, those treated only with PP finishing resin, those treated with commercial PP finishing softners and PP finishing resin. Also from the bending resistance test, the two kinds of fabric samples treated with SSN-3 of 3% showed grade 5 and these were good enough in feeling.

CPT-based p-y analysis for mono-piles in sands under static and cyclic loading conditions

  • Kim, Garam;Kyung, Doohyun;Park, Donggyu;Lee, Junhwan
    • Geomechanics and Engineering
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    • v.9 no.3
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    • pp.313-328
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    • 2015
  • In the present study, a CPT-based p-y analysis method was proposed for offshore mono-piles embedded in sands. Static and cyclic loading conditions were both taken into account for the proposed method. The continuous soil profiling capability of CPT was an important consideration for the proposed method, where detailed soil profile condition with depth can be readily incorporated into the analysis. The hyperbolic function was adopted to describe the non-linear p-y curves. For the proposed hyperbolic p-y relationship, the ultimate lateral soil resistance $p_u$ was given as a function of the cone resistance, which is directly introduced into the analysis as an input data. For cyclic loading condition, two different cyclic modification factors were considered and compared. Case examples were selected to check the validity of the proposed CPT-based method. Calculated lateral displacements and bending moments from the proposed method were in good agreement with measured results for lateral displacement and bending moment profiles. It was observed the accuracy of calculated results for the conventional approach was largely dependent on the selection of friction angle that is to be adopted into the analysis.

High temperature resistance of self-compacting lightweight mortar incorporating expanded perlite and pumice

  • Karatas, Mehmet;Balun, Bilal;Benli, Ahmet
    • Computers and Concrete
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    • v.19 no.2
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    • pp.121-126
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    • 2017
  • This paper presents the effect of aggregate type on high temperature resistance of self-compacting mortars (SCM) produced with normal and lightweight aggregates like expanded perlite and pumice. Silica fume (SF) and fly ash (FA) were used as mineral additives. Totally 13 different mixtures were designed according to the aggregate rates. Mini slump flow, mini V-funnel and viscometer tests were carried out on the fresh mortar. On the other hand, bulk density, porosity, water absorption and high temperature tests were made on the hardened SCM. After being heated to temperatures of 300, 600 and $900^{\circ}C$, respectively, the tensile strength in bending and compressive strength of mortars determined. As a result of the experiments, the increase in the use of lightweight aggregate increased total water absorption and porosity of mortars. It is observed that, the increment in the usage of lightweight aggregate decreased tensile strength in bending and compressive strengths of mortar specimens exposed to high temperatures but the usage of up to 10% expanded perlite in mortar increased the compressive strength of specimens exposed to $300^{\circ}C$.

Preparation and Physical Properties of Silicone Softner for PP Finish (PP 가공용 실리콘 유연제의 제조와 물성연구)

  • Im, Wan-Bin;Yang, In-Mo;Jung, Choong-Ho;Hahm, Hyun-Sik;Park, Hong-Soo
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.2
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    • pp.117-122
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    • 2002
  • A silicone softner (SS-5), a permanent press (PP) finish, was prepared by blending silicone oil KF-96 (as a lubricating component) and beef tallow hardened oil (as a softening component) which was synthesized from fatty polyamide salts. The prepared SS-5 and the PP finishing resin were applied to PP finishing cotton cloth and P/C gingham sample by one-bath method. The properties such as crease recovery, tear strength, and bending resistance were tested. The samples treated with SS-5 and PP finishing resin showed improved properties when comparing with the untreated ones, with the ones treated only with PP finishing resin, with ones treated with commercial PP finishing softners and PP finishing resin. The grades of fabric samples treated with 3% SS-5 were fifth grade in the bending resistance test.

Characteristics of a Flexible Transparent Electrode based on a Silver Nanowire-polymer Composite Material with a Mesh Pattern Formed without Lithography (리소그래피 없이 제작된 그물망 구조의 은나노와이어-고분자화합물 복합소재 기반 유연 투명전극의 특성)

  • Park, Tae Gon;Park, Jong Seol;Park, Jin Seok
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.4
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    • pp.11-17
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    • 2020
  • In this study, a new method for fabricating flexible transparent electrodes based on silver nanowire-polymer (AgNW-PEDOT:PSS) composite materials having a mesh pattern formed by a solution-based process without lithography was proposed. By optimizing conditions such as the amount of ultraviolet (UV) photosensitizer injected into the suspension of AgNW and PEDOT:PSS, UV exposure time, and deionized (DI) washing time, a clear and uniform mesh pattern was obtained. For the fabricated AgNW-PEDOT:PSS-based mesh-type electrodes, characteristics such as electrical sheet resistance, light transmittance, haze, and bending flexibility were analyzed according to the mixing ratio of AgNW and PEDOT:PSS included in the suspension. The fabricated mesh electrodes typically exhibited a low electrical sheet resistance of less than 20 Ω/sq while maintaining a high transmittance of 80% or more. In addition, it was confirmed from the results of analyzing the effect of PEDOT:PSS on the characteristics of the mesh-type AgNW-PEDOT electrode that the optical visibility was greatly enhanced by reducing the surface roughness and haze, and the bending flexibility was remarkably improved.

Behaviors of novel sandwich composite beams with normal weight concrete

  • Yan, Jia-Bao;Dong, Xin;Wang, Tao
    • Steel and Composite Structures
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    • v.38 no.5
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    • pp.599-615
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    • 2021
  • The ultimate strength behaviour of sandwich composite beams with J-hooks and normal weight concrete (SCSSBJNs) are studied through two-point loading tests on ten full-scale SCSSBJNs. The test results show that the SCSSBJN with different parameters under two-point loads exhibits three types of failure modes, i.e., flexure, shear, and combined shear and flexure mode. SCSSBJN failed in different failure modes exhibits different load-deflection behaviours, and the main difference of these three types of behaviours exist in their last working stages. The influences of thickness of steel faceplate, shear span ratio, concrete core strength, and spacing of J-hooks on structural behaviours of SCSSBJN are discussed and analysed. These test results show that the failure mode of SCSSBJN was sensitive to the thickness of steel faceplate, shear span ratio, and concrete core strength. Theoretical models are developed to estimate the cracking, yielding, and ultimate bending resistance of SCSSBJN as well as its transverse cross-sectional shear resistance. The validations of predictions by these theoretical models proved that they are capable of estimating strengths of novel SCSSBJNs.

Effect of core shape on debonding failure of composite sandwich panels with foam-filled corrugated core

  • Malekinejadbahabadi, Hossein;Farrokhabadi, Amin;Rahimi, Gholam H;Nazerigivi, Amin
    • Steel and Composite Structures
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    • v.45 no.3
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    • pp.467-482
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    • 2022
  • One of the major failure modes in composite sandwich structures is the separation between skins and core. In this study, the effect of employing foam filled composite corrugated core on the skin/core debonding (resistance to separation between skin and core) is investigated both experimentally and numerically. To this aim, triangular corrugated core specimens are manufactured and compared with reference specimens only made of PVC foam core in terms of skin/core debonding under bending loading. The corrugated composite laminates are fabricated using the hand layup method. Also, the Vacuumed Infusion Process (VIP) is employed to join the skins to the core with greater quality. Utilizing an End Notched Shear (ENS) fixture, three point bending tests are performed on the manufactured sandwich composite panels. The results reveal that the resistance to separation capacity and flexural stiffness of sandwich composite has been increased about 170% and 76%, respectively by using a triangular corrugated core. The Cohesive Zone Model (CZM) with appropriate cohesive law in ABAQUS finite element software is used to model the progressive face/core interfaces debonding the difference between experimental and numerical results in predicting the maximum born load before the skin/core separation is about 6 % in simple core specimens and 3% in triangular corrugated core specimens.