• Title/Summary/Keyword: Linear Structure Model

Search Result 1,186, Processing Time 0.038 seconds

A Study on Forced Vibration Tests on a Structure with Stud Type of Vibration Control Damper (스터드형 진동제어 강재댐퍼가 장착된 3층 강구조 골조의 강제진동실험에 관한 연구)

  • Lee, Seung-Jae
    • Journal of Korean Association for Spatial Structures
    • /
    • v.6 no.2 s.20
    • /
    • pp.115-121
    • /
    • 2006
  • In recent years vibration control damper made of low yield point steel is expected to play an important role in controlling structural vibration induced earthquake and wind. But their dynamic characteristics and energy dissipation effects on the whole structure model are not clarified. In this paper, firstly, we presents the results of cyclic tests on low yield steel dampers. Secondly, forced vibration tests on existence three stories steel structure model with low yield point steel dampers are presented. Lastly, it is estimated energy amount which is dissipated through the hysteresis dampers by using two types of analytical models, hysteresis model and equivalent linear model.

  • PDF

Acoustic Source Tracker Based on Pseudo-Linear DOA Estimator for Autonomous Robots (자율이동로봇 이동음원 추적센서 개발을 위한 의사선형 도래각 추정기법)

  • Lim, Jae-Il;Ra, Won-Sang
    • Proceedings of the KIEE Conference
    • /
    • 2011.07a
    • /
    • pp.1788-1789
    • /
    • 2011
  • In order to develop a one-axis gimbaled acoustic source tracker for mobile robots, a pseudo-linear direction of arrival(DOA) estimator is proposed using a linear ultrasonic sensor array. Under the assumption that the sensor measurement errors are negligible, a linear measurement model is derived using the linear prediction relation of the received sinusoidal acoustic signals. Applying the Kalman filtering technique for this model, the linear recursive DOA estimator is designed. For its linear recursive filter structure, it is preferable for real-time implementation on a commercial DSP. Through the experiments, the effectiveness of the suggested method is demonstrated.

  • PDF

An application study of the optimal multi-variable structure control to the state space model of the robot system (로보트 시스템의 State space 모델에 대한 최적 다중-변화 구조제어의 응용연구)

  • 이주장
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1986.10a
    • /
    • pp.321-325
    • /
    • 1986
  • A new control scheme for the state space model of the robot system using the theory of optimal multi-variable structure is presented in this paper. It is proposed to optimize multi-dimensional variable structure systems for obtaining the required stabilizing signal by minimizing a performance index with respect to the state vector in the sliding mode. It is concluded the proposed variable structure controller yields better system dynamic performance than that obtained by using the only linear optimal controller inthat responses for a step disturbance have a shorter setting time, no matter what overshoot values and rising time.

  • PDF

A Study on the Non-linear Analysis of Steel Frame with Semi-rigid Connections (반강접성을 고려한 강뼈대 구조물의 비선형 해석에 관한 연구)

  • 이종석;이상엽;김정훈
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1997.10a
    • /
    • pp.111-118
    • /
    • 1997
  • Generally, H-section is used for columns and beams in the middle and low building steel structure, But it has a axis and a weak axis. Thus if H-section is used for columns, the structure needs reinforcement on the weak axis. Therefore recently, square hollow section(S.H.S) is used for columns because it is able to cover the vulnerability of H-section. Structural analysis is usually executed under the assumption that connections are either ideally pinned joint or fully joint. Actually all connections are semi-rigid which possess a rotational stiffness. Therefore it can be designed economically as using the property of connections which has a rotational stiffness. This paper presents a prediction model curve which is fitted with Kishi-Chen Power Model about the behavior of connection between H-beam and S.H.S column in the previous experimental paper. It also suggests the new analysis algorithm considering the non-linear of semi-rigid connection and the geometrical non-linear under the effect of axial force.

  • PDF

Structural joint modeling and identification: numerical and experimental investigation

  • Ingole, Sanjay B.;Chatterjee, Animesh
    • Structural Engineering and Mechanics
    • /
    • v.53 no.2
    • /
    • pp.373-392
    • /
    • 2015
  • In the present work, structural joints have been modeled as a pair of translational and rotational springs and frequency equation of the overall system has been developed using sub-structure synthesis. It is shown that using first few natural frequencies of the system, one can obtain a set of over-determined system of equations involving the unknown stiffness parameters. Method of multi-linear regression is then applied to obtain the best estimate of the unknown stiffness parameters. The estimation procedure has been developed first for a two parameter joint model and then for a three parameter model, in which cross coupling terms are also included. Two cases of structural connections have been considered, first with a cantilever beam with support flexibility and then a pair of beams connected through lap joint. The validity of the proposed method is demonstrated through numerical simulation and by experimentation.

Seismic Response Analysis of a Base-Isolated Structure Supported on High Damping Rubber Bearings (고감쇠 면진베어링에 의해 지지된 면진구조물의 지진응답해석)

  • Yoo, Bong;Lee, Jae-Han;Koo, Gyeong-Hoi
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1995.04a
    • /
    • pp.99-106
    • /
    • 1995
  • The seismic responses of a base Isolated Pressurized Water Reactor(PWR) are investigated using a mathematical model which expresses the superstructure as a linear lumped mass-spring and the seismic Isolator as an equivalent spring-damper. Time history analyses are performed for the 1940 El Centre earthquake with linear amplification. In the analysis 5% of structural damping is used for the superstructure. The effects of high damping rubber bearing on seismic response of the superstructure in base isolated system are evaluated for four stiffness model types. The acceleration responses in base isolated PWR superstructure with high damping rubber bearings are much smaller than those in fixed base structure. In the higher strain region where stiffness behaves non-linearly, the acceleration responses modelled by one equivalent stiffness are smaller than those in nonlinear spring model, and the higher stiffness spring model of isolator exhibits larger peak acceleration response at superstructure in the frequency range above 2.0 Hz. when subjected to linearly amplified 1940 El Centre earthquake.

  • PDF

Evaluation of Pile-Ground Interaction Models of Wind Turbine with Twisted Tripod Support Structure for Seismic Safety Analysis (지진 안전도 해석을 위한 Twisted Tripod 지지 구조를 갖는 풍력발전기의 말뚝-지반 상호작용 모델 평가)

  • Park, Kwang-yeun;Park, Wonsuk
    • Journal of the Korean Society of Safety
    • /
    • v.33 no.1
    • /
    • pp.81-87
    • /
    • 2018
  • The seismic response, the natural frequencies and the mode shapes of an offshore wind turbine with twisted tripod substructure subject to various pile-ground interactions are discussed in this paper. The acceleration responses of the tower head by four historical earthquakes are presented as the seismic response, while the other loads are assumed as ambient loads. For the pile-ground interactions, the fixed, linear and nonlinear models are employed to simulate the interactions and the p-y, t-z and Q-z curves are utilized for the linear and nonlinear models. The curves are designed for stiff, medium and soft clays, and thus, the seven types of the pile-ground interactions are used to compare the seismic response, the acceleration of the tower head. The mode shapes are similar to each other for all types of pile-ground interactions. The natural frequencies, however, are almost same for the three clay types of the linear model, while the natural frequency of the fixed support model is quite different from that of the linear interaction model. The wind turbine with the fixed support model has the biggest magnitude of acceleration. In addition, the nonlinear model is more sensitive to the stiffness of clay than the linear pile-ground interaction model.

Analytical model of isolated bridges considering soil-pile-structure interaction for moderate earthquakes

  • Mohammad Shamsi;Ehsan Moshtagh;Amir H. Vakili
    • Geomechanics and Engineering
    • /
    • v.34 no.5
    • /
    • pp.529-545
    • /
    • 2023
  • The coupled soil-pile-structure seismic response is recently in the spotlight of researchers because of its extensive applications in the different fields of engineering such as bridges, offshore platforms, wind turbines, and buildings. In this paper, a simple analytical model is developed to evaluate the dynamic performance of seismically isolated bridges considering triple interactions of soil, piles, and bridges simultaneously. Novel expressions are proposed to present the dynamic behavior of pile groups in inhomogeneous soils with various shear modulus along with depth. Both cohesive and cohesionless soil deposits can be simulated by this analytical model with a generalized function of varied shear modulus along the soil depth belonging to an inhomogeneous stratum. The methodology is discussed in detail and validated by rigorous dynamic solution of 3D continuum modeling, and time history analysis of centrifuge tests. The proposed analytical model accuracy is guaranteed by the acceptable agreement between the experimental/numerical and analytical results. A comparison of the proposed linear model results with nonlinear centrifuge tests showed that during moderate (frequent) earthquakes the relative differences in responses of the superstructure and the pile cap can be ignored. However, during strong excitations, the response calculated in the linear time history analysis is always lower than the real conditions with the nonlinear behavior of the soil-pile-bridge system. The current simple and efficient method provides the accuracy and the least computational costs in comparison to the full three-dimensional analyses.

Development of a Large Capacity Hybrid-Type Linear Motor Damper for the vibration Control of Building Structures (건축 구조물의 진동 제어용 하이브리드형 대용량 리니어 모터 댐퍼의 개발)

  • Jeong, Sang-Seop;Jang, Seok-Myeong;Lee, Seong-Ho;Yun, In-Gi
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.51 no.11
    • /
    • pp.601-611
    • /
    • 2002
  • As resent trends in structural construction have been to build taller and larger structures than any time in the past, they have had high flexibility and low damping that can cause large vibration response under severe environmental loading such as earthquakes, winds, and mechanical excitations. The damper with mass and sqring is one aproach to safeguarding the structure against excessive vibrations. In this paper, a large capacity hybrid-type linear motor damper(LMD) was designed and fabricated for the application to the vibration control of a large building structure model. It has been designed to be able to move the damper mass, 1,500 kg up to ${\pm}250mm$ strokes at the first mode natural frequency of the building structure model, ${\pm}0.51Hz$. Linear motor is consisted of the fixed coil and the movable NdFeB permanent magnets field part. The PM field part composed magnet modules and iron yoke, is the damper mass itself, 1500kg. LMD therefore has a simplified structure and requires a few elements in the driving system, being compared with a rotary motor damper and a hydraulic damper. However, the manufacture of large PM linear actuator is difficult because of the limit of PM size and the attraction and repulsion at the assembly of PM. Therefore, large damper system is manufactured and tested for dynamic characteristics and frequency response.

Linear Seismic Performance Evaluation Procedure of the Low-Rise Reinforced Concrete Facilities (저층 철근 콘크리트 시설물 선형 내진 성능 평가)

  • Kim, Doo-Hwan;Jeong, Ui-Do;Song, Kwan Kwon;Kim, Seong Pil
    • Journal of Korean Association for Spatial Structures
    • /
    • v.18 no.2
    • /
    • pp.129-135
    • /
    • 2018
  • Following a 5.8 magnitude earthquake on September 12, 2016 in Gyeongju Province, a magnitude 5.4 earthquake occurred in the northern region of Pohang City on November 15, 2017 in South Korea. Only 7.9 % of the building structures are earthquake-resistant, according to the recent survey conducted by the government agencies in October 2017. In this paper, the linear analysis seismic performance evaluation procedure of the existing school structures presented in the revised methodology(Seismic Performance Evaluation Procedure and Rehabilitation Manual for School Facilities) was introduced. In this paper, the linear analysis evaluation procedure presented in the revised methodology was introduced and the seismic performance index of the example structure was evaluated using the linear analysis evaluation procedure. The seismic retrofit was verified by the linear and nonlinear dynamic analyses using Perform 3D. The analysis results show that the dissipated inelastic energy is concentrated on the retrofitted shear wall and the maximum inter-story drift of the stadium model structure with damping system satisfies the requirement of the current code.