• Steel and Composite Structures
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• 제9권1호
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• pp.1-17
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• 2009

This paper is focused on the buckling and post buckling behaviour of rectangular corrugated board panels simply supported and subjected to compression load. The aim of the work is to understand the failure mechanism of investigated structure in order to quantify the effect of design parameters on the strength of a panel of given geometry. Two numerical models were developed adopting the finite element method. In the first one the corrugated board is represented by means of shell elements adopting an equivalent material, in the second the local structure is described in full detail modelling both straight and corrugated layers by means of shell elements and representing the connection between layers by special interface elements. The model correctness was checked by the comparison between out of plane central displacement predicted by the models and the experimental values found in literature. For the same case the effect of panel planarity error was evaluated. Finally a parametric analysis to investigate the effect of design parameters was carried out.

• Advances in Computational Design
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• 제1권4호
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• pp.357-370
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• 2016

This paper aims to examine the dynamic response of a newly designed ultrasonic motor under half-sine shock impulses. Impact shock was applied to the motor along x, y or z axis respectively with different pulse widths to check the sensitivity of the motor to the shocks in different directions. Finite Element Analysis (FEA) with the ANSYS software was conducted to obtain the relative displacement of a key point of the motor. Numerical results show that the maximum relative displacement is of micro meter level and the maximum stress is five orders smaller than the Young's modulus of the piezo material, which proves the robustness of the motor.

• Journal of Welding and Joining
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• 제33권6호
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• pp.55-59
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• 2015

Self-piercing riveting (SPR) is a sheet-joining method that can be used for materials that are difficult or unsuitable for weld, such as aluminum alloys and other steel sheet metals. The increased application of lightweight materials has initiated many investigations into new SPR conditions for riveting dissimilar materials. However, buckling of the semi-tubular rivet occurs during the riveting of AHSS. In this study, a helical SPR was designed for the riveting of AHSS and Al-alloy. In addition, the reinforced helical SPR which has straight parts was designed. The riveting of AHSS and Al-alloy was simulated. Simulated results were verified by comparison with experimental ones.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.262-269
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• 2004

Ship structures are basically an assembly of plate elements and the load-carrying capacity or the ultimate strength is one of the most important criteria for safety assessment and economic design. Also, Structural elements making up ship plated structures do not work separately, resulting in high degree of redundancy and complexity, in contrast to those of steel framed structures. To enable the behavior of such structures to be analyzed, simplifications or idealizations must essentially be made considering the accuracy needed and the degree of complexity of the analysis to be used. On this study, to investigate effect of analysis range, the finite element method are used and their results are compared varying the analysis ranges. The model has been selected from bottom panels of large merchant ship structures. For FEA, three types of structural modeling are adopted in terms of the extent of the analysis. The purpose of the present study is to numerically calculate the characteristics of ultimate strength behavior according to the analysis ranges of stiffened panels subject to uniaxial compressive loads.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.118-125
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• 2004

The assessment of fatigue property is one of the most indispensable factors to design mechanical structures or parts. For accurately assessing fatigue property, it is necessary to precisely identify the loading condition and material property of the objective structure. However, there are many kind of problems in conducting predictive activity for a design concerned with variable factor such as fatigue phenomenons and environments. Therefore, most of the fatigue problems have been assessed from exiting experiment data and prediction method. In this study, expert system is developed for simply conducting performance assessment of weldments based on Finite element Analysis carrying out performance improvement and safety assessment of welded structures.

• International Journal of Precision Engineering and Manufacturing
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• 제3권3호
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• pp.69-75
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• 2002

Measuring dynamic fracture toughness of brittle and small ceramic specimen is very difficult in a SHPB (Split Hopkinson Pressure Bar). As a countermeasure to this difficulty, a dynamic fracture toughness measuring method by the Chevron-notch ceramic specimen was proposed. Tested chevron specimens were of Chevron notch angles of 90$^{\circ}$, 100$^{\circ}$ and 110$^{\circ}$. Through finite element analysis, shape parameters of the Chevron-notch specimens according to notch angles were calculated. And the static fracture tough1ess of the Chevron-notch alumina specimen was measured as 3.8MPa√m similar to that of CT specimen with a precrack. Dynamic fracture toughness was 4.5MPa√m slightly higher than the static one. It was shown in this study that the proposed Chevron-notch specimens are valid to measure dynamic fracture toughness of extremely brittle materials such as ceramic.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권7호
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• pp.351-356
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• 2002

The oil circulation rate (OCR) of the rotary compressor is a crucial factor affecting the performance and reliability of air-conditioning systems. In this paper, topology optimization of the single-phase induction motor of rotary compressor is carried out for reducing the OCR. The nonlinear transient characteristic of single-phase induction motor for rotary compressor is analyzed by using FLUX2D. The topology optimization for electromagnetic systems is developed using the finite element method (FEM). The topology optimization is applied to a single-phase induction motor for reducing the OCR. For validation, optimize induction motors are manufactured and tested.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.404-407
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• 2004

Linear ultrasonic motor by bimorph. Transducer for linear ultrasonic motor with symmetric and anti-symmetric modes was studied. The transducer was composed of two piezoelectric ceramic that cross at right angles with each other at tip. In order to exist length vibration mode two piezoelectric ceramics must have 90-degree phase difference with each other. As a result, tip of transducer moves in elliptical motion. Elliptical trajectory of transducer was analyzed by employing the (mite element method(FEM). From the result, the linear ultrasonic motor was measured for characteristics. In this paper, vibration shape of transducer was simulated and the resonant frequency, stabilization frequency and maximum displacement were calculated using the FEA.

• 대한기계학회논문집A
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• 제31권1호
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• pp.105-112
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• 2007

The linkage framework of geometric modeling based on NURBS(Non-Uniform Rational B-Spline) surface and shell finite analysis is developed in the present study. For this purpose, geometrically exact shell finite element is implemented. NURBS technology is employed to obtain the exact geometric quantities for the analysis. Especially, because NURBS is the most powerful and wide-spread method to represent general surfaces in the field of computer graphics and CAD(Computer Aided Design) industry, the direct computation of surface geometric quantities from the NURBS surface equation without approximation shows great potential for the integration between geometrically exact shell finite element and geometric modeling in the CAD systems. Some numerical examples are given to verify the performance and accuracy of the developed linkage framework. In additions, trimmed surfaces with some cutouts are considered for more practical applications.

• 한국생산제조학회지
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• 제26권3호
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• pp.292-298
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• 2017

Numerical analysis for various design parameters should be preceded by optimal design of composite materials. Numerous studies have been conducted on the bolting of interconnecting beams. In this study, the response surface method was applied to optimize the design of bolted joints connected by laminated wood composite beams. The response surface was created by combining the FEA code for composite analysis and the algorithm for forming the response surface. Optimization on this response surface was performed with a genetic algorithm to derive the results. The determination of the optimum bolt-hole position for the connection of composite beams is an optimization problem. Tsai-Wu composite failure index, maximum deflection, and simple von Mises stress are set as the objective functions. It has been proved that the design results of the optimized bolt-hole are superior to the design performance of the existing conventional bolt-hole position.