• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.6
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• pp.645-657
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• 2015

In this study floor impact noise and structure acceleration response of bare concrete slabs were predicted by using Finite Element Analysis(FEA). Prediction results were compared with experimental results to prove the accuracy of numerical model. Acoustic absorption were addressed by using panel impedance coefficients with frequency characteristics and structural modal damping of numerical model were applied by modal testing results and analysis of prediction and test results. By using frequency response function, the floor acceleration and acoustic pressure responses for various impact sources were calculated at the same time. In the FEA, the natural frequencies and the shapes of vibration and acoustic modes can be estimated through the eigen-value analysis, and it can be visually seen the vibration and sound pressure field and the contribution of major modes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.969-974
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• 1994

The dynamic behavior of graphite/epoxy laminated composite shell structure due to low-velocity impact is investigated using the finite element method. In this analysis, the Newmark's constant-acceleration time integration algorithm is used. The impact response such as contact force, central deflection and dynamic strain history form shell structure analysis are compared with those form the plate non-linear analysis. The effects of curvature, impact velocity and mass of impactor on the composite shell are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.372-378
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• 2005

Finite element analysis of concrete slab system in apartment building was executed using the tables of orthogonal arrays, and optimal design process was proposed. At first, experimental results show that sound peak components to influence the overall level and the rating of floor impact sound insulation were coincident with natural frequencies of the reinforced concrete slab. Finite element model of concrete slab was compared with experimental results, and well corresponded with an error of less than 10%. The tables of orthogonal arrays were used for finite element analysis with 8 factors. 3 related to material properties and 5 related to slab shape parameters and its results were analyzed by statistical method, ANOVA. The most effective factor among them was slab thickness, and main effect factor from slab shape parameters was different from each natural frequency. The interaction was found in the higher mode over $3^{rd}$ natural frequency. From main effect plot and interaction plot, the optimal design factor to increase the natural frequency was determined.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.159-164
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• 2020

The response analysis of frame structure with open section beams considering warping conditions and short duration load have been performed. When a beam of frame structure is subjected under torsional moment, the cross section will deform a warping as well as twist. For some thin-walled sections warping will be large, and accompanying warping restraint will induce axial and shear stresses and reduce the twist of beam which stiffens the beam in torsion. Because of impact or blast loads, the wave propagation effects become increasingly important as load duration decreases. This paper presents that a warping restraint in finite element model effects the behavior of beam deformation, dynamic mode shape and response analysis. The computer modelling of frame is discussed in linear beam element model and linear thin shell element model, also presents a correlation between computer predicted and actual experimental results for static deflection, natural frequencies and mode shapes of frame. A method to estimate the number of normal modes that are important is discussed.

• Structural Engineering and Mechanics
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• v.77 no.2
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• pp.293-304
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• 2021

Structural failure due to seismic pounding between two adjacent buildings is one of the major concerns in the context of structural damage. Pounding between adjacent structures is a commonly observed phenomenon during major earthquakes. When modelling the structural response, stiffness of impact spring elements is considered to be one of the most important parameters when the impact force during collision of adjacent buildings is calculated. Determining valid and realistic stiffness values is essential in numerical simulations of pounding forces between adjacent buildings in order to achieve reasonable results. Several impact model stiffness values have been presented by various researchers to simulate pounding forces between adjacent structures. These values were mathematically calculated or estimated. In this study, a linear spring impact element model is used to simulate the pounding forces between two adjacent structures. An experimental model reported in literature was adopted to investigate the effect of different impact element stiffness k on the force intensity and number of impacts simulated by Finite Element (FE) analysis. Several numerical analyses have been conducted using SAP2000 and the collected results were used for further mathematical evaluations. The results of this study concluded the major factors that may actualise the stiffness value for impact element models. The number of impacts and the maximum impact force were found to be the core concept for finding the optimal range of stiffness values. For the experimental model investigated, the range of optimal stiffness values has also been presented and discussed.

• Structural Engineering and Mechanics
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• v.83 no.2
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• pp.179-193
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• 2022

The shear behaviour of reinforced concrete members has been studied over the past decades by various researchers, and it can be simulated by analysing shear panel elements which has been regarded as a basic element of reinforced concrete members subjected to in-plane biaxial stresses. Despite various experimental studies on shear panel element which have been conducted so far, there are still a lot of uncertainties related to what influencing factors govern the shear behaviour and affect failure mechanism in reinforced concrete members. To identify the uncertainties, a finite element analysis can be used, which enables to investigate the impact of specific variables such as the reinforcement ratio, the shear retention factor, and the material characteristics including aggregate interlock, tension stiffening, compressive softening, and shear behaviour at the crack surface. In this study, a non-linear probabilistic analysis was conducted on reinforced concrete panels using a finite element method optimized for reinforced concrete members and advanced sampling techniques so that probabilistic analysis can be performed effectively. Consequently, this study figures out what analysis methodology and input parameters have the most influence on shear behaviour of reinforced concrete panels.

• Journal of KSNVE
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• v.6 no.4
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• pp.493-497
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• 1996

TVs or computer monitors with speakers often have a phenomenon called microphonic which shows fringe-like dark pattern on their screens. The major source of this phenomenon is vibration of the shadow mask inside of the Cathode RAY Tube(CRT) which is caused by the sound generated from the speakers. Reducing phenomenon microphonic by modifying the structure of the shadow mask frame in CRT has been examined in this study. A 15" for computer monitor were chosen. Using finite element analysis for vibration and impact, shape of the shadow mask frame was found to reduce microphonic phenomeon. Improved 15" monitors showed good results.d results.

• 연구논문집
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• s.22
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• pp.65-74
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• 1992

This paper aims at calculating optimum design dimensions to minimize the weight satisfied strain and stress intensity of the frame while loading maximum weight into a mechanical press in the static condition. Analysis of the frame was carried out by using the FEM, then the optimum condition was obtained by using these data. As modeling in the finite element analysis has great impact on the reliablity of analysis results, the analyzed object was selected a 150-ton mechanical press of J Company, the part little affected to structural rigidity was simplified, the load condition was considered in the only maximum load, the boundary condition was used by giving symmetric displacement due to symmetric boundary condition, the finite element was applied a linear membrane element. An intermediate processor program applied the normal ANSYS to analyze finite elements was developed, and the design sensitivity was calculated. This program was applied to the optimum design.

• Geomechanics and Engineering
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• v.32 no.5
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• pp.513-521
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• 2023

Temperature is one of the most critical elements that influence the rutting and fatigue resistance of flexible pavements. Particularly in extreme hot regions in Saudi Arabia, high temperature would significantly reduce the rutting resistance of flexible pavements leading to reduction of pavement service life. Due to the impacts of global warming, average temperature in Saudi Arabia is expected to further increase by about 4℃ by the end of the 21st century. The substantial increase in average temperature will elevate the expected pavement maintenance and rehabilitation cost. This paper analyzes the structural effects of temperature on pavement using layered elastic analysis based on finite element techniques. The research team calculated the potential loss of pavement service life due to the projected temperature increase and climate change. The paper also analyzed potential impact of using carbon waste in asphalt concrete to tackle the derogatory impacts of temperature rise.

• Coupled systems mechanics
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• v.11 no.4
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• pp.285-295
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• 2022

Laminated composite plates are utilized extensively in different fields of construction and industry thanks to their advantages such as high stiffness-to-weight ratio. Additionally, they are characterized by their directional properties that permit the designer to optimize their stiffness for specific applications. This paper presents a numerical analysis and optimization study of plates made of composite subjected to low velocity impact. The main aim is to identify the optimum fiber orientations of the composite plates that resist low velocity impact load. First, a three-dimensional finite element model is built using LS DYNA computer software package to perform the impact analyses. The composite plate has been modeled using solid elements. The failure criteria of Tsai-Wu's criterion have been used to control the strength of the composite material. A good agreement has been found between the predicted numerical results and experimental results in the literature which validate the finite element model. Then, an Adaptive Simulated Annealing (ASA) has been used to optimize the response of impacted composite laminate where its objective is to maximize the safety factor by varying the ply angles. The results show that the ASA is robust in the sense that it is capable of predicting the best optimal designs.