• Title/Summary/Keyword: cyclic behavior

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A Study on Clay Behavior Characteristics Based on Non-Linear Kinematic Hardening Rule (비선형 이동경화법칙에 기초한 점성토의 거동 특성)

  • Kim, Yong-Seong
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.4
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    • pp.114-122
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    • 2002
  • Up to now, many constitutive models for clay have been proposed and studied based on the elasto-plastic or elasto-viscoplastic theory and it has been recognized that the effect of time on the loading process is a salient feature. In the present study, cyclic behavior characteristics of clay was studied with a viscoelastic-viscoplastic constitutive model for clay based on the non-linear kinematic hardening rule. In order to examine the behavior of clay several cyclic untrained triaxial tests and also their numerical simulations were performed. As results of that, it was found that the proposed model can well describe cyclic behaviors of clay such as frequency dependent characteristics, and have the high feasibility of numerical simulation for dynamic analysis.

An endochronic model of material function and its application to plastic behavior of metals under asymmetric cyclic loadings

  • Yeh, Wei-Ching;Lin, Hsi-Yen;Jhaot, Jhen-Bo
    • Structural Engineering and Mechanics
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    • v.25 no.4
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    • pp.423-444
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    • 2007
  • By using the incremental form of the endochronic theory of plasticity, a model of material function is proposed in this paper to investigate plastic behavior. By comparing the stress-strain hysteresis loop, the theory is shown to agree well with the experimental results, especially in the evolution of peak stress values of SAE 4340 steel loaded by cyclic loading with various amplitudes. Depending on the choice of material parameters, the present model can substantially result in six categories of material function, each of which can behave differently with respect to an identical deformation history. In addition, the present model of material function is shown to be capable of describing the behavior of erasure of memory of materials, as experimentally observed by Lamba and Sidebottom (1978).

Research on the Bond Behavior of FRP Rebars subjected to Cyclic Loading (반복하중을 받는 FRP 보강근의 부착성능에 대한 연구)

  • Chang, Mun-Suk;Lee, Jung-Yoon;Park, Ji-Sun;Park, Young-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.205-208
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    • 2006
  • The use of Fiber Reinforced Polymer (FRP) bars has been gaining popularity in the civil engineering community, as an alternative material to steel reinforcement, for their noncorrosive nature and high strength-to-weight ratio. Good performance of reinforced concrete requires adequate interfacial bond between the reinforcing material and the concrete because the load applied must be transferred from the matrix to the reinforcement. Although studies on the FRP bond behavior under monotonic loading has been reported by many, there are very little work done under cyclic loading. In this paper, we present the experimental study on the bond behavior of three different types of FRP rebars subjected to four different cyclic loading conditions.

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Numerical cyclic behavior of T-RBS: A new steel moment connection

  • Ataollahi, Saeed;Banan, Mohammad-Reza;Banan, Mahmoud-Reza
    • Steel and Composite Structures
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    • v.21 no.6
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    • pp.1251-1264
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    • 2016
  • After observing relatively poor performance of bolted web-welded flange beam-to-column connections during 1994 Northridge earthquake, various types of connections based on two concepts of: (i) strengthening the connection; and (ii) weakening the beam ends were proposed. Among these modified or newly proposed connections, bolted T-stub connection follows the concept of strengthening. One of the connections with the idea of weakening the beam ends is reduced beam section (RBS). In this paper, finite element simulation is used to study the cyclic behavior of a new proposed connection developed by using a combination of both mentioned concepts. Investigated connections are exterior beam-to-column connections designed to comply with AISC provisions. The results show that moment capacity and dissipated energy of the new proposed connection is almost the same as those computed for a T-stub connection and higher than corresponding values for an RBS connection.

The behavior of high-speed rail roadbed reinforced by geogrid under cyclic loading (지오그리드로 보강한 고속철도 노반의 동적 거동)

  • 신은철;김두환;김종인
    • Proceedings of the KSR Conference
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    • 1999.11a
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    • pp.415-422
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    • 1999
  • The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. Five series of test were conducted with varying the soil profile conditions including the ground level, type of soil, and the thickness of each soil layer. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to know the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

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Characteristics of Friction Behavior of Ceramic Friction Materials according to Surface Materials

  • Ji-Hun Park;Jung-Woo Lee;Jong-Won Kwark;Woo-Jin Han;Oneil Han
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.535-541
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    • 2023
  • Friction material, an integral constituent of bearing supports, facilitates frictional interactions between two components. Polytetrafluoroethylene (PTFE), a commonly employed friction material in bearing supports, has assessed resultant friction equilibrium. Nonetheless, protracted utilization diminishes frictional performance as the lubricating agent is progressively depleted. Friction materials can affect the entire structural system. Hence, this study applied ceramic material as a friction material due to its high strength, low friction, and low deformation. The frictional behavior was investigated using a cyclic friction test, considering various friction materials as the primary design variables and examining their covariance in cyclic frictional movements. The results substantiated that the ceramic friction material yielded a low variance and friction coefficients in cyclic frictional movements.

Simulations of the hysteretic behavior of thin-wall cold-formed steel members under cyclic uniaxial loading

  • Dong, Jun;Wang, Shiqi;Lu, Xi
    • Structural Engineering and Mechanics
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    • v.24 no.3
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    • pp.323-337
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    • 2006
  • In this paper, the hysteretic behaviors of channel and C-section cold-formed steel members (CFSMs) under cyclic axial loading were simulated with the finite element method. Geometric and material nonlinearities, Bauschinger effect, strain hardening and strength improvement at corner zones were taken into account. Extensive numerical results indicated that, as the width-to-thickness ratio increases, local buckling occurs prematurely. As a result, the hysteretic behavior of the CFSMs degrades and their energy dissipation capability decreases. Due to the presence of lips, the hysteretic behavior of a C-section steel member is superior to that of its corresponding channel section. The intermediate stiffeners in a C-section steel member postpone the occurrence of local buckling and change its shapes, which can greatly improve its hysteretic behavior and energy dissipation capability. Therefore, the CFSMs with a large width-to-thickness ratio can be improved by adding lips and intermediate stiffeners, and can be used more extensively in residential buildings located in seismic areas.

Experimental and numerical investigations on the ratcheting characteristics of cylindrical shell under cyclic axial loading

  • Shariati, M.;Hatami, H.;Torabi, H.;Epakchi, H.R.
    • Structural Engineering and Mechanics
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    • v.44 no.6
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    • pp.753-762
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    • 2012
  • The ratcheting characteristics of cylindrical shell under cyclic axial loading are investigated. The specimens are subjected to stress-controlled cycling with non-zero mean stress, which causes the accumulation of plastic strain or ratcheting behavior in continuous cycles. Also, cylindrical shell shows softening behavior under symmetric axial strain-controlled loading and due to the localized buckling, which occurs in the compressive stress-strain curve of the shell; it has more residual plastic strain in comparison to the tensile stress-strain hysteresis curve. The numerical analysis was carried out by ABAQUS software using hardening models. The nonlinear isotropic/kinematic hardening model accurately simulates the ratcheting behavior of shell. Although hardening models are incapable of simulating the softening behavior of the shell, this model analyzes the softening behavior well. Moreover, the model calculates the residual plastic strain close to the experimental data. Experimental tests were performed using an INSTRON 8802 servo-hydraulic machine. Simulations show good agreement between numerical and experimental results. The results reveal that the rate of plastic strain accumulation increases for the first few cycles and then reduces in the subsequent cycles. This reduction is more rapid for numerical results in comparison to experiments.

Creep of stainless steel under heat flux cyclic loading (500-1000℃) with different mechanical preloads in a vacuum environment using 3D-DIC

  • Su, Yong;Pan, Zhiwei;Peng, Yongpei;Huang, Shenghong;Zhang, Qingchuan
    • Smart Structures and Systems
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    • v.24 no.6
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    • pp.759-768
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    • 2019
  • In nuclear fusion reactors, the key structural component (i.e., the plasma-facing component) undergoes high heat flux cyclic loading. To ensure the safety of fusion reactors, an experimental study on the temperature-induced creep of stainless steel under heat flux cyclic loading was performed in the present work. The strains were measured using a stereo digital image correlation technique (3D-DIC). The influence of the heat haze was eliminated, owing to the use of a vacuum environment. The specimen underwent heat flux cycles ($500^{\circ}C-1000^{\circ}C$) with different mechanical preloads (0 kN, 10 kN, 30 kN, and 50 kN). The results revealed that, for a relatively large preload (for example, 50 kN), a single temperature cycle can induce a residual strain of up to $15000{\mu}{\varepsilon}$.

Inelastic and Local Buckling Behavior of H-Beams with Web Opening under Cyclic Loadings (반복하중을 받는 H형강 유공보의 소성 및 국부좌굴 거동)

  • Lee, Eun Taek;Kim, Cheol Hwan;Oh, Woo Hun
    • Journal of Korean Society of Steel Construction
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    • v.15 no.3
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    • pp.271-279
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    • 2003
  • Many researches have been conducted to describe the elastic and inelastic behavior of H-shaped beams with web openings, and were generally concentrated on the uniaxial loading conditions. With previous research results, the formulae for the design of beams with web openings, considering local buckling, have been proposed by Darwin. Although the formulae are so simple and useful to apply to real situations, it needs more research on cyclic loading conditions. In this experimental study, a total of seven H-shaped beams with circular web openings under cyclic loading conditions were investigated. The dimension criteria were based on the formulae proposed by Darwin. The suitability of the existing design formulae, the effects of plastic hinges on beams with web openings, and the local bucking around the web openings to the beam strength under cyclic loading were also investigated through by the observations of the behavior of these beams with various dimensional openings.