• 소성∙가공
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• 제14권1호
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• pp.49-56
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• 2005

In the semi-solid die casting process, an important thing is the flow behavior of semi-solid materials. The flow patterns of the semi-solid material can make the defects during die filling. To control the flow patterns is very important and difficult. In this paper, the flow behavior of the semi-solid A356 alloy material during die filing at various die gate shapes has been observed with the grain size controlled material. The effect of the gate shape on the die filling characteristics was investigated. The filling tests in each plunger stroke were experimented, and also simulated on the semi-solid material die casting process by MAGMAsoft. According to the filling tests and computer simulation, the effect of the gate shape on liquid segregation has been investigated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.132-137
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• 2012

To enhance the CAE accuracy, the definition of material behavior is one of key influence on the result. In case of plastic material with fiber reinforcement, the anisotropic material behavior should be taken into account to increase of CAE accuracy. BASF has developed an innovative CAE tool, ULTRASIM$^R$, which is capable of generating material models of thermoplastic materials for structural simulation. ULTRASIM$^R$, not only the glass fiber orientation effect, but also the weld line effect, tensile-compression anisotropy, strain rate effect are combined in a non-linear material law, which will be evaluated in a unique failure criterion, thus resulting in an highly accurate CAE approach.

• Computers and Concrete
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• 제25권5호
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• pp.471-478
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• 2020

In this work, the analytical solution for the stresses in piezo-thermo-elastic homogeneous, transversely isotropic material under the effect of the rotation has investigated. The thermoelasticity theory has used to study the problem. The material subjected to boundary conditions. Finally, the numerical solution has carried out piezo - thermo-elastic material under the effect of rotation, to illustrate the analytical development. The corresponding simulated results of various physical quantities such as the displacements and the stresses, the temperature and the electrical displacement have presented graphically.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.345-346
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• 2018

In this study, various materials such as epoxy material, urethane material, cement material, and acrylic material are used to solve the water leakage occurring in underground structures. However, in the reality that the durability is insufficient and the effect is insufficient, it is aimed to improve the repairing effect by using cement and acrylics n combination. As a first study, we tried to verify the performance of rapid micro cement and cement paste and to improve the performance by checking the product properties. Three types of micro cement are evaluated. Three types of micro cement are used: fiber inclusion, fiber unfolding, and cement paste. When the material is selected for micro cement, it is applied to the field to understand the maintenance effect and durability.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.223-224
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• 2017

In this study, various materials such as epoxy material, urethane material, cement material, and acrylic material are used to solve the water leakage occurring in underground structures. However, in the reality that the durability is insufficient and the effect is insufficient, it is aimed to improve the repairing effect by using cement and acrylics in combination. As a first study, we tried to verify the performance of improve the performance by checking the product properties according to the composition ratio of polyacrylic resin. Polyacrylic resin is evaluated in three different composition ratios. When the material is selected for polyacrylic resin, it is applied to the field to understand the maintenance effect and durability.

• 대한기계학회논문집A
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• 제30권8호
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• pp.931-940
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• 2006

Defect assessment of a weld zone is important in fitness-for-service evaluation of plant components. Typically a J and $C^*$ estimation method for a defective homogeneous component is extended to a mismatched component, by incorporating the effect due to the strength mismatch between the weld metal and the base material. The key element is a mismatch limit load. For instance, the R6/R5 procedure employs an equivalent material concept, defined by a mismatch limit load. A premise is that if a proper mismatch limit load solution is available, the same concept can be used for any defect location (either a weld centre defect or a heat affected zone (HAZ) defect) and for any material combination (either two-material or multi-material combinations; either similar or dissimilar joints). However, validation is still limited, and thus a more systematic investigation is needed to generalise the suggestion to any geometry, any defect location and any material combination. This paper describes the effect of structural geometry on the $C^*$ integral for defective similar welds, based on systematic elastic-creep 2-D and 3-D finite element (FE) analyses, to attempt to elucidate the questions given above. It is found that the existing 'equivalent material' concept is valid only for limited cases, although it provides conservative estimates of $C^*$ for most of cases. A modification to the existing equivalent material concept is suggested to improve accuracy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.337-338
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• 2007

• Advances in concrete construction
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• 제12권5호
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• pp.377-389
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• 2021

Reinforced concrete vertical silos are universal structures that store large amounts of granular materials. Due to the asymmetric structure, heavy load, uneven storage material distribution, and the difference between the storage volume and the storage material bulk density, the corresponding earthquake is very complicated. Some scholars have proposed the calculation method of horizontal forces on reinforced concrete vertical silos under the action of earthquakes. Without considering the effect of torsional effect, this article aims to reveal the expansion factor of the silo group considering the torsional effect through experiments. Through two-way seismic simulation shaking table tests on reinforced concrete column-supported group silo structures, the basic dynamic characteristics of the structure under earthquake are obtained. Taking into account the torsional response, the structure has three types of storage: empty, half and full. A comprehensive analysis of the internal force conditions under the material conditions shows that: the different positions of the group bin model are different, the side bin displacement produces a displacement difference, and a torsional effect occurs; as the mass of the material increases, the structure's natural vibration frequency decreases and the damping ratio Increase; it shows that the storage material plays a role in reducing energy consumption of the model structure, and the contribution value is related to the stiffness difference in different directions of the model itself, providing data reference for other researchers; analyzing and calculating the model stiffness and calculating the internal force of the earthquake. As the horizontal side shift increases in the later period, the torsional effect of the group silo increases, and the shear force at the bottom of the column increases. It is recommended to consider the effect of the torsional effect, and the increase factor of the torsional effect is about 1.15. It can provide a reference for the structural safety design of column-supported silos.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.621-633
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• 2006

To reflect the size effect of material $(1\sim15{\mu}m)$ during plastic deformation of polycrystalline copper, a constitutive equation which includes the strain gradient plasticity theory and intrinsic material length model is coupled with the finite element analysis and applied to plane strain deformation problem. The method of least square has been used to calculate the strain gradient at each element during deformation and the effect of distributed force on the strain gradient is investigated as well. It shows when material size is less than the intrinsic material length $(1.54{\mu}m)$, its deformation behavior is quite different compared with that computed from the conventional plasticity. The generation of strain gradient is greatly suppressed, but it appears again as the material size increases. Results also reveal that the strain gradient leads to deformation hardening. The distributed force plays a role to amplify the strain gradient distribution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.23-26
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• 2002

In ceramic systems using LTCC, many components including embedded passives and TRL's are used for composition of 3-dimensional circuit. So the exact analysis on this components must be performed. As for the TRL's, material properties including electrical conductivity of metal, loss factor and effective dielectric constant of dielectric material and geometrical factors like roughness of surface, vias, dimension of TRL structure have a large effect on the characteristics of transmission lines. Such properties of materials have different values in each system with ideal ones presented in text book. In this research, the effective material properties in each system are examined and the effect of material properties and geometrical factors on the characteristics of TRL's are analyzed and quantified by simulation and measurement.