Earticle

This study investigates the vibration characteristics of an aluminum subframe for small and high-speed vessels through modal and resonance analysis using the finite element method (FEM). Due to the low stiffness and damping of aluminum, concerns arise over structural resonance and fatigue. A 3D model based on actual design drawings was analyzed to extract six natural frequencies and corresponding mode shapes. Significant deformation was observed in the first and second modes (90.65 Hz, 110.60 Hz), which may overlap with operational frequencies. The fifth mode (263.70 Hz) showed high amplitude with Y-axis concentration, indicating lateral resonance vulnerability. Deformation ratios were used to identify dominant vibrational directions. Based on the findings, design strategies such as structural reinforcement, RPM adjustment, and damping device application were proposed to improve vibration safety in the early design stage.

Battery electrodes, essential for energy storage, possess pores that heavily influence their mechanical properties based on the level of porosity and the nature of the pores. The irregularities in pore shape, size, and distribution complicate the accurate determination of these properties. While stress-strain measurements can shed light on a material’s mechanical behavior and predict compression limits, the complex structure of the pores poses significant challenges for accurate measurements. In this research, we introduce a simulation-driven approach to derive stress-strain data that considers porosity. By calculating relative density and the rate of volume change under compression based on porosity, and applying pressure, we conducted a parametric study to identify the elastic modulus (E) in relation to the rate of volume change. This information was utilized within a material modeling equation, generating stress-strain (S-S) curves that were further analyzed to replicate the compression behavior of the electrode material. The outcomes of this study are expected to improve the prediction accuracy of mechanical properties for porous electrode materials, potentially enhancing battery performance and refining manufacturing processes.

In this study, we examined the assembly and components of a 40-feet container chassis based on its 3D shape. Utilizing the finite element method, we conducted structural analysis considering the total weight, including the 40-ton weight specified in automotive regulations, along with a safety margin of 1.5 under extreme load conditions. And also fixed and junction conditions were applied to the chassis system. Subsequently, we presented the maximum stress results derived from the structural analysis of both the overall chassis system and its individual components. Finally, we evaluated the structural stability of the 40-feet container chassis by comparing and reviewing the maximum stress with the yield strength of the material used for each component.

The increasing saturation challenges in storage facilities for Low- and Intermediate-Level Radioactive Waste call for a more efficient storage approach. Consequently, we have developed a square-structured container that features a storage capacity approximately 20% greater than that of conventional drum-type containers. Considering the need to contain various radioactive wastes from nuclear power usage securely until they no longer pose a threat to human health or the environment, this study focuses on evaluating the sealing efficacy of the newly designed rectangular container using finite element analysis. Since radioactive waste containers typically do not experience external forces except under special circumstances, our analysis simulated the impact of an external force, assuming a fall scenario. After fastening the bolts, we examined the vertical stress distribution on the container by applying the calculated external force. The analysis confirms the container's stable seal.

This review study discusses the utilization of Terrestrial Laser Scanner (TLS) 3D point cloud data in representing geometry for structural health monitoring (SHM) applications, particularly the so-called Scan-to-FEM method. The existing studies related to the topic are intensively presented and discussed along with the advantages and disadvantages of the modelling methods: meshing by whole and cross-section. Two case studies are conducted to show both modelling methods used for geometry representation for Scan-to-FEM method. Meshing by whole and cross-section methods result in the relative errors of respective 2.79% and 1.4% in the maximum displacement vector sum, compared to their reference models constructed by ABAQUS. It is also seen that the density and clarity of 3D point cloud data can bring well-shaped geometry for FE analysis and consequently produce good accuracy.

In the automobile manufacturing industry, lightweight design is one of the essential challenges to be solved fundamentally. The vehicle wheels are classified as safety related components as the main substructure of the vehicle. In this study, we illustrate a technique for selecting the appropriate number of spokes. Based on the basic model of the selected number of spokes, we propose a method to maintain stiffness and design lightweight using topology optimization software. Based on the basic model of the selected number of spokes, it was redesigned to be lightweight while maintaining stiffness by utilizing topology optimization software. By comparing and reviewing the structural analysis results of the basic model and the redesigned model, a design technique that can maintain structural safety and reduce wheel mass was proposed.

본 연구에서는 절연유 내 양극성 전하 수송 모델의 공간 전하 거동에 대한 물리적인 메커니즘을 분석하기 위해 유한요소법 기반의 다중물리 수치해석 모델링을 제안하였다. 수치해석을 모델은 2차원 평행 평판 전극사이에 약전해질로 구성된 절연유체를 포함하고 있다고 가정하였다. 전기장은 가우스 법칙으로부터 유도한 푸아송 방정식 으로 생성하고, 양극성 전하에 대한 연속방정식과 온도에 대한 열 확산 방정식을 지배방정식으로 구성하여 드리프 트-확산-전도에 대한 공간 전하 거동을 성공적으로 해석하였다. 공간 전하 전파 모델은 무차원화와 인공확산항을 도입하여 수치적으로 안정화하고 에너지법에 의한 전류 계산을 통해 다중물리 수치해석 모델링을 검증하였다. 최종 적으로 이온의 해리작용과 재결합작용을 고려한 공간 전하 수송 모델의 수치해석 결과를 동일한 조건에서 시험한 기존 문헌의 실험치와 비교분석을 통해 본 논문에서 제안하는 다중물리 수치해석법의 유용함을 검증하였다.

In this paper, multi-physics numerical analysis was developed utilizing finite element method to analyze mechanism of space charge behavior for bipolar charge transport model in dielectric liquid. In the numerical analysis model, it was assumed that the dielectric liquid composed of a weak electrolyte and contained between the two-dimensional parallel plate electrodes. An electric field was generated using Poisson's equation derived from Gauss's law, and multi-physics analysis by drift-diffusion-conduction of space charges was successfully performed by combining the bipolar charge continuity equation and the thermal diffusion equation by temperature. The space charge propagation model was numerically stabilized by applying non-dimensionalization and artificial diffusion terms, and multiphysics numerical analysis modeling was verified through current calculation by the energy method. Finally, the usefulness of the multi-physics numerical analysis method proposed in this paper was verified through comparative analysis with the experimental values of the previous literature that tested the numerical results of the space charge transport model considering the ionic dissociation and recombination of ions under the same conditions.

본 논문은 자동차 제동성능에 대한 운전자의 요구에 따라 브레이크 디스크 튜닝이 많이 이루어지고 있어, 자동 차에 사용되고 있는 순정 디스크와 튜닝제품으로 나오고 있는 디스크의 열적거동을 FEM해석을 통해 분석하였다. 순정 디스크 모델링 및 튜닝 디스크 Model-1, Model-2, Model-3로 모델링을 하고 디스크 회전속도를 1000rpm으로 설정 하여 해석을 실시하였다. 브레이크를 작동하면 디스크와 패드 접촉에 의해 발생하는 작동시 온도와 디스크 정지 후 마찰 면의 온도, 열 변형 등 디스크 표면의 열적거동에 대하여 분석하였다. 브레이크 작동시(0-4.5초) 온도는 순정 디스크보 다 튜닝 디스크가 34℃높게 나타났고, 디스크 정지 후(40.5초) 온도는 튜닝 디스크가 18℃낮게 분석되었으며, 디스크 열에 의한 변형은 튜닝 디스크가 0.3mm정도 많이 변형되었다. 순정 디스크와 튜닝 디스크의 열적거동에 따른 페이드 현상 등을 줄일 수 있는 효과는 있으나, 튜닝 디스크의 홀 가공 및 디스크 면 가공에 따른 열적거동에는 크게 변화가 없음을 관찰할 수 있었다.

This paper analyzes the thermal behaviors of genuine discs used in automobiles and discs coming out of tuning products through FEM analysis. Modeling with genuine disk modeling and tuning disks Model-1, Model-2, Model-3 and analyzing the disk rotation speed was set to 1000rpm. When the brake is operated, the thermal behavior of the disk surface, such as the operating temperature caused by the disk and pad contact, the friction surface temperature after the disk stop, and the thermal deformation, were analyzed. When the brake was activated (0-4.5 seconds), the tuning disk showed 34℃ higher than the original disk, and after the disk stopped (40.5 seconds), the tuning disk was analyzed 18℃ lowe, deformation due to the disk heat was deformed by 0.3mm for the tuning disk. Although there is an effect to reduce the fading phenomenon due to the thermal behavior of the pure disk and the tuning disk, it can be observed that there is no significant change in the thermal behavior due to the hole processing and the disk surface processing of the tuning disk.

In this study, the experiments and analyses were carried out in order to investigate the fracture characteristics on the adhesive at the specimen bonded with aluminum and aluminum-foam. The same conditions were given for the experiments and analyses. The results are investigated by the graph of reaction force according to displacement. It was found that the experimental and the analytical data were very similar to each other. On the basis of the data, the reliability of the analysis data could be confirmed. The notches were produced at the distances of 40, 110, 150, and 190 mm from the front of the test specimen, and the maximum reaction force was compared accordingly. It was found that the highest reaction force was generated at the front end of the adhesive and the lowest reaction force was found at the middle of the adhesive interface. Finally, when the equivalent stress in the test specimen was examined, it was found that the highest stress was obtained at the distance of 110 mm. It can be deduced. As the notch formation point are similar to the point when stress is dispersed as the adhesive is peeled off, it is possible to infer the high stress compared to other test specimens.

Modularization is an important benefit to overall project cost, such as construction period, manpower and logistics. In order to establish a successful modularization strategy, the optimum cost can be realized based on the Envelope Size which is allowed to be transferred to the plant site through analysis of each shape of the module. Through the analysis of the plant structure, the Envelope Size that can be transported on site in units of sizes suitable for maritime and onshore is provided, and finite element method is applied to the existing materials (A36, A572) and domestic materials (SS400, SM490, SWH400) and analyzed the results of the analysis to obtain domestic materials applicable to the plant structure frame.

공작기계의 주축은 황삭 가공에서 부터 정삭가공에 이르는 다양한 작업들이 가능해야 하고, 정속운동 또는 회전 위치결정의 기능을 수행해야 되므로 주축설계에 고려해야 할 변수들이 많다. 주축이동식자동선반은 고정식자동선반에 비해 샤프트가 가늘고 긴 핀 들을 작업할 때 좋은 선반이다. 고정식 자동선반에 비해 외경가공의 정밀도가 매우 높다. 주축 이송 형 선반은 주로 소형 제품을 정밀가공 할 경우에 사용되므로 가공 정밀도가 높아야 한다. 최대 외경 가공 한계 치수는 Ø32, 내경가공 한계 치수는 Ø6까지 가공이 가능하게 제작되어야 한다. 본 연구에서는 주축이동식 자동선반에 사용되는 SCM440 소재의 정·동적특성을 이동식 선반에 적용하여 분석하였다. 주축의 정,동적 특성에 영향을 미치는 인자들을 고려하여 고속 화 및 고정밀도를 갖는 최적설계기술이 확보하기 위하여 수치해석을 이용하여 분석하였다.

In the machine tool spindle, various tasks ranging from roughing to finishing must be possible, and the functions of constant speed movement or rotation positioning must be performed. Therefore, there are many variables to be considered in the spindle design. The Swiss Turn Type spindle automatic lathe is a good machine tool for working pins with thinner shafts than a fixed automatic lathe. The Swiss Turn Type spindle is mainly used for precision machining of small products, so the machining precision should be high. The maximum outer diameter limit shall be Ø32 and the inner diameter limit shall be Ø6. In this study, the static and dynamic characteristics of the SCM440 material used in the spindle type automatic lathe were analyzed by applying it to the Swiss turn type spindle automatic lathe. Numerical analysis was used to obtain optimal design technique with high speed and high accuracy considering the factors affecting the static and dynamic characteristics of the spindle.

자동차 디스크 브레이크시스템에서는 열유속 및 열변형 등과 같은 이유로 마찰열이 균일하게 분산되지 않는다. 마찰열에 의한 열탄성 변형이 접촉압력 분포에 영향을 미치게 되고, 접촉하중이 디스크 브레이크 표면상의 작은 영역에 집중되어 열탄성 불안정성을 초래 할 수 있다. 본 연구에서는 실험적 계산식과 Kao 제안한 디스크와 패드의 접촉압력에 대한 해석방법을 참고로 하여 3차원 축대칭 모델을 통하여 실제로 제동 시 발생되는 디스크와 패드의 접촉을 고려한 온도 해석 및 열변형 해석을 하였다. ANSYS를 사용하여 디스크와 패드의 접촉면에서 발생하는 열탄성 불안전성 문제를 열하중과 기계적 하중으로 동시에 고려하여 해석하였다. 디스크와 패드가 직접 접촉하는 3차원 축대칭 모델을 구성하여 디스크의 마찰면 온도, 열변형, 접촉 열응력을 관찰함으로써 디스크에서 일어나는 열적 거동을 보다 정확하게 관찰하였다.

In automotive disc brake systems, frictional heat is not uniformly dispersed for reasons such as heat flux and thermal deformation. The thermoelastic deformation due to the frictional heat affects the contact pressure distribution and the contact load may be concentrated on the contact portion on the the disc brake surface, resulting in thermoelastic instability. In this study, thermal analysis and thermal deformation analysis considering the contact between disk and pad occurred during braking through 3D axial symmetry model with reference to the experimental equation and Kao's analysis method of contact pressure of disk and pad. ANSYS is used to analyze the thermal and elastic instability problems occurring at the contact surface between the disk and the pad, considering both the thermal and mechanical loads. A 3D axisymmetric model with direct contact between the disk and the pad was constructed to more accurately observe the thermal behavior of the disk by observing the frictional surface temperature, thermal deformation and contact thermal stress of the disk.

In this paper, we propose the implementation of the simulation program for microstrip antenna analysis. The simulation program consists of the pre-processor, main-processor, and post-processor. The information generated at each stage is passed by the form of a text file. The pre-processor is implemented by the simple design program, and using the Finite Element Method that divide the analysis region into finite elements. The main-processor is implemented by using the Moment Method. The post-processor includes current density, S-parameter, smith chart, and radiation pattern. The analysis results are displayed graphically. The MFC based on C++ language is used for implementation of Graphical User Interface.

In this study the structure analysis of tapping machine is developed to improve dynamic characteristics. To this purpose a tapping m/c is mathematically modelled and dynamic response analysis of the model are investigated by use of Finite Element Method(FEM). The investigation procedures are as follows. The finite element modelling of the tapping m/c is done with triangular and rectangular plate elements and each node of the elements has 6 degrees of freedom. And this model is idealized as a forced vibration system under impulse load by cutting force. Model parameters, natural frequency and mode shape, and dynamic response for displacement and stress are analyzed by use of mode superposition method. To reduce computing time of dynamic response analysis, lower vibration mode is analyzed with master-DOF and mass participation factor. In this case maximum relative displacement is occured at 17.483 Hz in the right column.

A hierarchical computational method has been developed and used with finite element method based on dislocation density multiple-slip crystalline formulation to predict how nanoindentation affects behavior in face-centered cubic crystalline aggregates. Using displacement profiles which were obtained from molecular dynamics(MD) nanoindentation simulation, scaling relations based on indentation depths, grain-sizes, and grain aggregate distributions were obtained. These relations then applied to coarsen grains in micros- tructurally based FE formulation which accounts for dislocation density evolution, crystalline structures. This computational regime was validated with a several experimental results related to single gold crystals. This hierarchical model provides a tool to link nanosacle level with a microstructurally based FEM formulation that can be to ascertain inelastic effects such as dislocation density evolution. With the above certainty temperature distribution during the nanoindentation simulation also was investigated along with the different indentation depth.

Recently, Effective Width Beam Method has widely been researched in analysis method of Flat-Plate Slab System which is by the action of lateral load. Effective Width Beam Method is also useful especially in a general-purpose program, so it is being used widely. Actually, Effective Width Beam Method is mainly focused on lateral displacement which can happen in a plane that has a same span when lateral load is given and column-slab connection unbalance Moment, but studies about a plane which is a irregular span has not been studied enough. So we found that in condition of Flat-Plate Slab system which has irregular span plane when lateral load is given, output of lateral displacement is not much related with span, but column-Slab connection unbalance moment is influenced much by span after comparing the output of Column-Slab Connection Unbalance Moment and lateral displacement which are applied to Effective Width Beam Method with the Finite Element Method which has the exact output in Flat-Plate Slab system.