• Title/Summary/Keyword: static nonlinear

Search Result 1,082, Processing Time 0.022 seconds

Influence of Joint on Retrofitting Effect by Exterior Steel Frames of Existing RC Buildings (외부접합공법의 내진보강효과에 미치는 접합부의 영향)

  • Ahn, Choong Weon;Min, Chan Gi;Noh, Eun Choul;Han, Hong Soo;Kim, Tae Wan
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.19 no.4
    • /
    • pp.183-194
    • /
    • 2015
  • In this paper, Nonlinear Static Pushover analysis method(NSP) is proposed which apply to RC buildings reinforced by external retrofit for seismic performance. Based on previous analysis and research, NSP is more developed by connection nonlinearity according to shear resistance mechanism such as dowel and adhesive resistance as major shear resistance elements. According to the proposed method, structural analysis for example buildings was carried out to evaluate seismic performance of buildings. And, it was confirmed that depending on shear strain and characteristics of joint resistant of external retrofitting are different from internal retrofitting. Furthermore, the strength reduction coefficient of the anchor needs to be considered at the joint design.

Ship's Maneuverability in Strong Wind

  • Im, Nam-Kyun;Tran, Van-Luong
    • Journal of Navigation and Port Research
    • /
    • v.32 no.2
    • /
    • pp.115-120
    • /
    • 2008
  • This paper deals with effect of wind forces and moment acting on the training ship SAE NURI. The results of drift angle and counter rudder angle due to wind effect are calculated by using the static equilibrium method especially with nonlinear mathematical expression, and then the critical wind velocity is found out. The given results can be applied directly to T/S SAE NURI in handling under the wind condition and used for merchant ships as a referential tool.

A general method for active surface adjustment of cable net structures with smart actuators

  • Wang, Zuowei;Li, Tuanjie
    • Smart Structures and Systems
    • /
    • v.16 no.1
    • /
    • pp.27-46
    • /
    • 2015
  • Active surface adjustment of cable net structures is becoming significant when large-size cable net structures are widely applied in various fields, especially in satellite antennas. A general-duty adjustment method based on active cables is proposed to achieve active surface adjustment or surface profile reconfiguration of cable net structures. Piezoelectric actuators and voice coil actuators are selected for constructing active cable structures and their simplified mechanical models are proposed. A bilevel optimization model of active surface adjustment is proposed based on the nonlinear static model established by the direct stiffness method. A pattern search algorithm combined with the trust region method is developed to solve this optimization problem. Numerical examples of a parabolic cable net reflector are analyzed and different distribution types of active cables are compared.

Effect of column loss location on structural response of a generic steel moment resisting frame

  • Rezvani, Farshad Hashemi;Jeffers, Ann E.;Asgarian, Behrouz;Ronagh, Hamid Reza
    • Steel and Composite Structures
    • /
    • v.25 no.2
    • /
    • pp.217-229
    • /
    • 2017
  • The effect of column loss location on the structural response of steel moment resisting frames (MRF) is investigated in this study. A series of nonlinear static and dynamic analyses were performed to determine the resistance of a generic frame to an arbitrary column loss and detect the structural members that are susceptible to failure progression beyond that point. Both force-controlled and deformation-controlled actions based on UFC 4-023-03 and ASCE/SEI 41-06 were implemented to define the acceptance criteria for nine APM cases defined in this study. Results revealed that the structural resistance against an arbitrary column loss in the top story is at least 80% smaller than that of the bottom story. In addition, it was found that the dynamic increase factor (DIF) at the failure point is at most 1.13.

High-speed Two-photon Laser Scanning Microscopy Imaging of in vivo Blood Cells in Rapid Circulation at Velocities of Up to 1.2 Millimeters per Second

  • Boutilier, Richard M.;Park, Jae Sung;Lee, Ho
    • Current Optics and Photonics
    • /
    • v.2 no.6
    • /
    • pp.595-605
    • /
    • 2018
  • The two-photon process of microscopy provides good spatial resolution and optical sectioning ability when observing quasi-static endogenous fluorescent tissue within an in vivo animal model skin. In order to extend the use of such systems, we developed a two-photon laser scanning microscopy system capable of also capturing $512{\times}512$ pixel images at 90 frames per second. This was made possible by incorporating a 72 facet polygon mirror which was mounted on a 55 kRPM motor to enhance the fast-scan axis speed in the horizontal direction. Using the enhanced temporal resolution of our high-speed two-photon laser scanning microscope, we show that rapid processes, such as fluorescently labeled erythrocytes moving in mouse blood flow at up to 1.2 mm/s, can be achieved.

Lateral performance of CRCS connections with tube plate

  • Jafari, Rahman;Attari, Nader K.A.;Nikkhoo, Ali;Alizadeh, Saeid
    • Steel and Composite Structures
    • /
    • v.32 no.1
    • /
    • pp.37-57
    • /
    • 2019
  • This paper presents experimental and analytical studies to evaluate the cyclic behaviour of Circular Reinforced Concrete column Steel beam (CRCS) connections. Two 3/4-scale CRCS specimens are tested under quasi-static reversed cyclic loading. Specimens were strengthened with a tube plate (TP) and a steel doubler plate (SDP). Furthermore; nine interior beam-through type RCS connections are simulated using nonlinear three-dimensional finite element method using ABAQUS software and are verified with experimental results. The results revealed that using the TP improves the performance of the panel zone by providing better confinement to the concrete. Utilizing the TP at the panel zone may absorb and distribute stress in this region. Results demonstrate that TP can be used instead of SDP. Test records indicate that specimens with TP, with and without SDP maintained their maximum strength up to 4% drift angle, satisfying the recommendation given by AISC341-2016 for composite special moment-resisting frames.

Structural Behavior of Reinforced Concrete Slab Rigid-frame Bridge with H-Shaped Steel Girders

  • Nakai, Yoshiaki;Ha, Tuan Minh;Fukada, Saiji
    • International journal of steel structures
    • /
    • v.18 no.4
    • /
    • pp.1219-1241
    • /
    • 2018
  • This study aims towards the improvement of a reinforced concrete rigid-frame bridge in an effort to reduce the construction and maintenance costs, and achieve an improved seismic performance. Correspondingly, a new structural rigid connection is proposed for H-shaped steel girders and reinforcing bars at the corner of the rigid-frame structure. Both experiments and numerical analyses were performed. Prototype models were constructed and subjected to static loading tests to reveal their load-carrying capacity and failure mode. Numerical models were then developed using finite elements to evaluate the experimental results. Analyses elicited good agreement between simulation and experimental data and validated the numerical models. Moreover, the validity of the proposed rigid connection was confirmed, and the failure behavior was clarified. Finally, a full-size model of the reinforced concrete rigid-frame bridge with H-shaped steel girders was constructed and subjected to destructive loading tests to evaluate structural integrity of the proposed rigid connection.

Frequency and thermal buckling information of laminated composite doubly curved open nanoshell

  • Dai, Humin;Safarpour, Hamed
    • Advances in nano research
    • /
    • v.10 no.1
    • /
    • pp.1-14
    • /
    • 2021
  • In the present computational approach, thermal buckling and frequency characteristics of a doubly curved laminated nanopanel with the aid of Two-Dimensional Generalized Differential Quadrature Method (2D-GDQM) and Nonlocal Strain Gradient Theory (NSGT) are investigated. Additionally, the temperature changes along the thickness direction nonlinearly. The novelty of the current study is in considering the effects of laminated composite and thermal in addition of size effect on frequency, thermal buckling, and dynamic deflections of the laminated nanopanel. The acquired numerical and analytical results are compared by each other to validate the results. The results demonstrate that some geometrical and physical parameters, have noticeable effects on the frequency and pre-thermal buckling behavior of the doubly curved open cylindrical laminated nanopanel. The favorable suggestion of this survey is that for designing the laminated nano-sized structure should pay special attention to size-dependent parameters because nonlocal and length scale parameters have an important role in the static and dynamic behaviors of the laminated nanopanel.

Behavior factors for mixed reinforced concrete wall and buckling restrained braced frame

  • Hamid Beiraghi;Behdad Abbaspour
    • Structural Engineering and Mechanics
    • /
    • v.86 no.2
    • /
    • pp.277-290
    • /
    • 2023
  • A supplementary reinforced concrete wall can be used to improve the seismic behavior of a buckling restrained braced frame as a mixed system. In such a novel system, the total lateral force is resisted by the combination of the RC wall system and the BRBF. There is not enough research on the response modification factor of such a mixed system. This paper investigates the response modification factor, and such relevant factors as ductility reduction factor and over strength factor for a system consisting of reinforced concrete wall and buckling restrained braced frame. To this purpose, nonlinear incremental dynamic analysis as well as static push over analysis are used for 6- to 14-story sample structures. The results show that for mixed considered systems, the mean value of response modification factor varies approximately from 7 to 9.

GWO-based fuzzy modeling for nonlinear composite systems

  • ZY Chen;Yahui Meng;Ruei-Yuan Wang;Timothy Chen
    • Steel and Composite Structures
    • /
    • v.47 no.4
    • /
    • pp.513-521
    • /
    • 2023
  • The goal of this work is to create a new and improved GWO (Grey Wolf Optimizer), the so-called Robot GWO (RGWO), for dynamic and static target tracking involving multiple robots in unknown environmental conditions. From applying ourselves with the Gray Wolf Optimization Algorithm (GWO) and how it works, as the name suggests, it is a nature-inspired metaheuristic based on the behavior of wolf packs. Like other nature-inspired metaheuristics such as genetic algorithms and firefly algorithms, we explore the search space to find the optimal solution. The results also show that the improved optimal control method can provide superior power characteristics even when operating conditions and design parameters are changed.