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Jeom Kee Paik - One of the best experts on this subject based on the ideXlab platform.

  • full scale collapse testing of a steel stiffened Plate Structure under cyclic axial compressive loading
    Structures, 2020
    Co-Authors: Jeom Kee Paik, Dae Kyeom Park, Jonas W Ringsberg
    Abstract:

    Plate panels of ships and floating offshore Structures are likely subjected to cyclic loads arising from waves at sea. Depending on sea states, e.g., whipping in harsh sea states, the maximum amplitude of the cyclic loads may reach over 70% of ultimate loads. Of concerns is how the cyclic loads will affect the ultimate strength compared to a case of monotonically increasing loads. The aim of this paper is to experimentally investigate the ultimate strength characteristics of a steel stiffened Plate Structure under cyclic axial-compressive loading. A full-scale collapse testing in association with bottom Structures of an as-built 1,900 TEU containership was conducted. It is concluded that the effects of cyclic loading on the ultimate compressive strength of steel stiffened Plate Structures are small as far as fatigue damages are not suffered due to the small number of load cycles and/or local structural members do not reach the ultimate strength during cyclic axial-compressive loading. Details of the test database are documented, which will be useful to validate computational models for the ultimate strength analysis.

  • full scale collapse testing of a steel stiffened Plate Structure under axial compressive loading triggered by brittle fracture at cryogenic condition
    Ships and Offshore Structures, 2020
    Co-Authors: Jeom Kee Paik, Dae Kyeom Park, Jonas W Ringsberg
    Abstract:

    This paper is a sequel to the authors’ earlier article (Paik et al. 2020a, Full-scale collapse testing of a steel stiffened Plate Structure under cyclic axial-compressive loading, Structures, https://doi.org/10.1016/j.istruc.2020.05.026). The aim of the paper was to present a test data on the ultimate compressive strength characteristics of a full-scale steel stiffened Plate Structure at cryogenic condition which may be due to unwanted release of liquefied gases. Steel Plate panels of an as-built containership carrying 1,900 TEU were referenced for this purpose. The test Structure was fabricated in a shipyard using exactly the same welding technology as used in today’s shipbuilding industry. It is observed that the test Structure reaches the ultimate limit states triggered by brittle fracture, which is totally different from typical collapse modes at room temperature. Details of the test database are documented as they can be used to validate computational models for the structural crashworthiness analysis involving brittle fracture at cryogenic condition.

Jonas W Ringsberg - One of the best experts on this subject based on the ideXlab platform.

  • full scale collapse testing of a steel stiffened Plate Structure under cyclic axial compressive loading
    Structures, 2020
    Co-Authors: Jeom Kee Paik, Dae Kyeom Park, Jonas W Ringsberg
    Abstract:

    Plate panels of ships and floating offshore Structures are likely subjected to cyclic loads arising from waves at sea. Depending on sea states, e.g., whipping in harsh sea states, the maximum amplitude of the cyclic loads may reach over 70% of ultimate loads. Of concerns is how the cyclic loads will affect the ultimate strength compared to a case of monotonically increasing loads. The aim of this paper is to experimentally investigate the ultimate strength characteristics of a steel stiffened Plate Structure under cyclic axial-compressive loading. A full-scale collapse testing in association with bottom Structures of an as-built 1,900 TEU containership was conducted. It is concluded that the effects of cyclic loading on the ultimate compressive strength of steel stiffened Plate Structures are small as far as fatigue damages are not suffered due to the small number of load cycles and/or local structural members do not reach the ultimate strength during cyclic axial-compressive loading. Details of the test database are documented, which will be useful to validate computational models for the ultimate strength analysis.

  • full scale collapse testing of a steel stiffened Plate Structure under axial compressive loading triggered by brittle fracture at cryogenic condition
    Ships and Offshore Structures, 2020
    Co-Authors: Jeom Kee Paik, Dae Kyeom Park, Jonas W Ringsberg
    Abstract:

    This paper is a sequel to the authors’ earlier article (Paik et al. 2020a, Full-scale collapse testing of a steel stiffened Plate Structure under cyclic axial-compressive loading, Structures, https://doi.org/10.1016/j.istruc.2020.05.026). The aim of the paper was to present a test data on the ultimate compressive strength characteristics of a full-scale steel stiffened Plate Structure at cryogenic condition which may be due to unwanted release of liquefied gases. Steel Plate panels of an as-built containership carrying 1,900 TEU were referenced for this purpose. The test Structure was fabricated in a shipyard using exactly the same welding technology as used in today’s shipbuilding industry. It is observed that the test Structure reaches the ultimate limit states triggered by brittle fracture, which is totally different from typical collapse modes at room temperature. Details of the test database are documented as they can be used to validate computational models for the structural crashworthiness analysis involving brittle fracture at cryogenic condition.

Lauren T Shumate - One of the best experts on this subject based on the ideXlab platform.

  • Secondary ossification center induces and protects growth Plate Structure
    eLife, 2020
    Co-Authors: Meng Xie, Pavel Gol'din, Anna Nele Herdina, Jordi Estefa, Ekaterina Medvedeva, Phillip Newton, Svetlana Kotova, Boris Shavkuta, Aditya Saxena, Lauren T Shumate
    Abstract:

    Growth Plate and articular cartilage constitute a single anatomical entity early in development but later separate into two distinct Structures by the secondary ossification center (SOC). The reason for such separation remains unknown. We found that evolutionarily SOC appears in animals conquering the land - amniotes. Analysis of the ossification pattern in mammals with specialized extremities (whales, bats, jerboa) revealed that SOC development correlates with the extent of mechanical loads. Mathematical modeling revealed that SOC reduces mechanical stress within the growth Plate. Functional experiments revealed the high vulnerability of hypertrophic chondrocytes to mechanical stress and showed that SOC protects these cells from apoptosis caused by extensive loading. Atomic force microscopy showed that hypertrophic chondrocytes are the least mechanically stiff cells within the growth Plate. Altogether, these findings suggest that SOC has evolved to protect the hypertrophic chondrocytes from the high mechanical stress encountered in the terrestrial environment.

Intan Zaurah Mat Darus - One of the best experts on this subject based on the ideXlab platform.

  • Active vibration control of a horizontal flexible Plate Structure using intelligent proportional–integral–derivative controller tuned by fuzzy logic and artificial bee colony algorithm:
    Journal of Low Frequency Noise Vibration and Active Control, 2019
    Co-Authors: Hadi, M. O. Tokhi, Intan Zaurah Mat Darus, M. F. Jamid
    Abstract:

    © The Author(s) 2019. This paper presents the development of an intelligent controller for vibration suppression of a horizontal flexible Plate Structure using hybrid Fuzzy–proportional–integral–derivative controller tuned by Ziegler–Nichols tuning rules and intelligent proportional–integral–derivative controller tuned by artificial bee colony algorithm. Active vibration control technique was implemented during the development of the controllers. The vibration data obtained through experimental rig was used to model the system using system identification technique based on auto-regressive with exogenous input model. Next, the developed model was used in the development of an active vibration control for vibration suppression of the horizontal flexible Plate system using proportional–integral–derivative controller. Two types of controllers were proposed in this paper which are the hybrid Fuzzy–proportional–integral–derivative controller and intelligent proportional–integral–derivative controller tuned by artificial bee colony algorithm. The performances of the developed controllers were assessed and validated. Proportional–integral–derivative–artificial bee colony controller achieved the highest attenuation for first mode of vibration with 47.54 dB attenuation as compared to Fuzzy–proportional–integral–derivative controller with 32.04 dB attenuation. The experimental work was then conducted for the best controller to confirm the result achieved in the simulation work.

  • AuCC - Active vibration control of flexible Plate with free-free-clamped-clamped edges using genetic algorithm
    2013 Australian Control Conference, 2013
    Co-Authors: Muhamad Sukri Hadi, Intan Zaurah Mat Darus, Hanim Mohd Yatim
    Abstract:

    This paper presents an investigation of system modeling using genetic algorithm and active vibration control of flexible Plate Structure. The experimental rig was designed and fabricated with free-free-clamped-clamped edges boundary condition in this research. The experimental study was conducted using experimental rig complete with data acquisition and instrumentation system to collect the input-output data of flexible Plate Structure. This input-output data used to develop the system identification to obtain a dynamic model of flexible Plate based on auto-regressive with exogenous input Structure. The developed model using genetic algorithm were validated using mean squared error, one step-ahead prediction and correlation test. The fitness function of genetic algorithm is mean squared error between the measured and estimated outputs of flexible Plate. The validations of developed model were presented in time domain and frequency domain. The modeling of flexible Plate using genetic algorithm was used in active vibration control system design for vibration suppression on the Plate Structure. The performance of developed controller assessed in term of spectral attenuation obtained for resonance modes.

  • Intelligence Swarm Model Optimization of Flexible Plate Structure System
    International review of automatic control, 2013
    Co-Authors: Muhamad Sukri Hadi, Intan Zaurah Mat Darus
    Abstract:

    This paper presents the performance of modeling the flexible Plate Structure with free-free-clamped-clamped (FFCC) edges boundary condition using conventional Recursive Least Squares (RLS) and evolutionary algorithm of Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The auto-regressive with exogenous (ARX) Structure was used in this study to obtain the dynamic model of a flexible Plate Structure. Data acquisition and instrumentation system were designed and integrated with the experimental rig and several experimental procedures were conducted to acquire the input and output of the flexible Plate. The input and output data collected from the experimental study were utilized to develop the model of the system. The 4000 data sets collected in the experiment were divided into two parts for training and testing. The first 3000 data sets were used to train the model developed while the last 1000 data sets were used to test the performance of thus developed model. All developed model using RLS, GA and PSO were validated using one step-ahead prediction (OSA), mean squared error (MSE) and correlation tests. Amongst all, it was found that PSO algorithm has performed better in term of lowest mean squared error achieved (0.00032719) as compared to conventional algorithm (RLS) and evolutionary algorithm (GA). However, by comparing in term of estimating the first mode of vibration which the dominant mode of Structure, GA has performed better by presented the lowest percentage error (3.63 %). Besides that, it was found that, all estimated models using all methods proposed are comparable, acceptable and possible to be used as a platform of controller development and verification to suppress the vibration of the flexible Plate Structure.

  • Non-parametric modelling of a rectangular flexible Plate Structure
    Engineering Applications of Artificial Intelligence, 2012
    Co-Authors: Intan Zaurah Mat Darus, A. A. Al-khafaji
    Abstract:

    This research investigates the performance of dynamic modelling using non-parametric techniques for identification of a flexible Structure system for development of active vibration control. In this paper, the implementation details are described and the experimental studies conducted in this research are analysed. The input-output data of the system were first acquired through the experimental studies using National Instruments (NI) data acquisition system. A sinusoidal force was applied to excite the flexible Plate and the dynamic response of the system was then investigated. Non-parametric modelling of the system were developed using several artificial intelligent methodologies namely Adaptive Elman Neural Networks (ENN), Backpropagation Multi-layer Perceptron Neural Networks (MLPNN) and Adaptive Neuro-Fuzzy Inference System (ANFIS). The performance of all these methodologies were compared and discussed. Finally, validation and verification of the obtained model was conducted using One Step Ahead (OSA) prediction, mean squared error (MSE) and correlation tests. The prediction ability of the model was further observed with unseen data. The results verified that the MLPNN converge to an optimum solution faster and the dynamic model obtained described the flexible Plate Structure very well. The non-parametric models of the flexible Plate Structure thus developed and validated will be used as the representation of the transfer function of the system in subsequent investigations for the development of active vibration control strategies for vibration suppression in flexible Structures.

  • Self-learning active vibration control of a flexible Plate Structure with piezoelectric actuator
    Simulation Modelling Practice and Theory, 2010
    Co-Authors: Ali Reza Tavakolpour, Musa Mailah, Intan Zaurah Mat Darus, Osman Tokhi
    Abstract:

    Abstract In this paper, an active vibration control (AVC) incorporating active piezoelectric actuator and self-learning control for a flexible Plate Structure is presented. The flexible Plate system is first modelled and simulated via a finite difference (FD) method. Then, the validity of the obtained model is investigated by comparing the Plate natural frequencies predicted by the model with the reported values obtained from literature. After validating the model, a proportional or P-type iterative learning (IL) algorithm combined with a feedback controller is applied to the Plate dynamics via the FD simulation platform. The algorithms were then coded in MATLAB to evaluate the performance of the control system. An optimized value of the learning parameter and an appropriate stopping criterion for the IL algorithm were also proposed. Different types of disturbances were employed to excite the Plate system at different excitation points and the controller ability to attenuate the vibration of observation point was investigated. The simulation results clearly demonstrate an effective vibration suppression capability that can be achieved using piezoelectric actuator with the incorporated self-learning feedback controller.

Meng Xie - One of the best experts on this subject based on the ideXlab platform.

  • Secondary ossification center induces and protects growth Plate Structure
    eLife, 2020
    Co-Authors: Meng Xie, Pavel Gol'din, Anna Nele Herdina, Jordi Estefa, Ekaterina Medvedeva, Phillip Newton, Svetlana Kotova, Boris Shavkuta, Aditya Saxena, Lauren T Shumate
    Abstract:

    Growth Plate and articular cartilage constitute a single anatomical entity early in development but later separate into two distinct Structures by the secondary ossification center (SOC). The reason for such separation remains unknown. We found that evolutionarily SOC appears in animals conquering the land - amniotes. Analysis of the ossification pattern in mammals with specialized extremities (whales, bats, jerboa) revealed that SOC development correlates with the extent of mechanical loads. Mathematical modeling revealed that SOC reduces mechanical stress within the growth Plate. Functional experiments revealed the high vulnerability of hypertrophic chondrocytes to mechanical stress and showed that SOC protects these cells from apoptosis caused by extensive loading. Atomic force microscopy showed that hypertrophic chondrocytes are the least mechanically stiff cells within the growth Plate. Altogether, these findings suggest that SOC has evolved to protect the hypertrophic chondrocytes from the high mechanical stress encountered in the terrestrial environment.

  • secondary ossification center induces and protects growth Plate Structure
    bioRxiv, 2020
    Co-Authors: Meng Xie, Anna Nele Herdina, Jordi Estefa, Pavel Goldin, Ekaterina V Medvedeva, Phillip T Newton, Svetlana L Kotova, Boris Shavkuta
    Abstract:

    Abstract Growth Plate and articular cartilage constitute a single anatomical entity early in development, but later separate into two distinct Structures by the secondary ossification center (SOC). The reason for such separation remains unknown. We found that evolutionarily SOC appears in animals conquering the land - amniotes. Analysis of ossification pattern in mammals with specialized extremities (whales, bats, jerboa) revealed that SOC development correlates with the extent of mechanical loads. Mathematical modelling revealed that SOC reduces mechanical stress within the growth Plate. Functional experiments revealed high vulnerability of hypertrophic chondrocytes to mechanical stress and showed that SOC protects these cells from apoptosis caused by extensive loading. Atomic force microscopy showed that hypertrophic chondrocytes are the least mechanically stiff cells within the growth Plate. Altogether, these findings suggest that SOC has evolved to protect the hypertrophic chondrocytes from the high mechanical stress encountered in the terrestrial environment.