In this study, the performance evaluation of steel dampers was conducted based on existing research results. The test variables are cross-sectional shape and lateral deformation prevention details. As a result of performance tests according to cross-sectional shape, the circular cross-section was evaluated to be superior than the rectangular cross-section in terms of envelope, stiffness reduction, and energy dissipation capacity. In addition, it was evaluated that the rectangular cross-section where lateral deformation occurs can be restrained by lateral deformation prevention details, thereby improving strength and deformation capacity.

In the development of eco-friendly vehicles such as electric vehicles, weight reduction has become a very important design target. Seat weight reduction is very important in vehicle weight reduction. In this study, the energy absorption characteristics of Almag material, an alloy of aluminum and magnesium, and mild steel SAFH440, SAFH590, SAFC780, and SAFH980 were analyzed to obtain a true stress versus true strain curve that was correlated with the test. By performing the seat frame structure analysis using the obtained analysis material property, it was possible to compare the deformation between lightweight material, Almag and mild steel materials. In addition, it was confirmed that the weight reduction effect was 25.8% when applying Almag, an equivalent lightweight material that gives the same maximum deformation as SAFH980, a high-strength mild steel.

윌리엄 블레이크는 『로스의 서』와 『로스의 노래』에서 신화적 상상력으로 천지창조와 시민들의 자유에 대한 열망을 노래한다. 로스는 영원한 선지자로서 독자들에게 블레이크의 상상력의 원형을 인식하도록 만드는 역할을 한다. 독자들은 블레이크의 페르소나인 로스를 통해서 그의 신화적 상상력의 감성을 음미할 수 있다. 블레이크는 『로스의 서』에서 자신의 관점으로 천지창조와 인간의 창조를 노래하였고, 『로스의 노래』에서 인간이 창조된 이후에 인간의 정신문화가 어떻게 진화하고 발전하는지를 노래하면서, 인간이 본원적 가치를 회복하기 위한 노력으로 혁명을 통해 자유를 되찾는 과정을 맛깔스럽게 시로 노래한다. 그래서 현대인들은 블레이크의 시들을 읽으면서 인간의 자유와 정신문화를 숙고해보고, 인간의 진정한 가치가 무엇인지를 성찰하는 시간을 갖게 한다.

PURPOSES : Concrete, which is a construction material, is the most widely used compression material; however, unlike steel, it exhibits nonlinear material characteristics. Therefore, to examine the behavior of structures under the nonlinear conditions of concrete materials, one must select an appropriate numerical-analysis technique and a reasonable material model. When performing the nonlinear numerical analysis of a structure using general-purpose structural analysis software, the stress–strain curve or the Mohr–Coulomb failure criterion is typically employed to consider the nonlinear material characteristics. In this study, an efficient nonlinear numerical analysis is conducted by defining the stress–strain curves and Mohr–Coulomb parameters applicable to Strand7 to examine and design the stability of reinforced concrete structures. METHODS : This study was conducted by improving existing data. Based on the tensile region of the concrete stress–strain curve presented in a simple shape and the results of the splitting test, the proposed Mohr–Coulomb parameter was improved based on regulations stipulated in the design standards of concrete structures. The characteristics and usability of the improved material models were examined using concrete splitting tensile and bending models. RESULTS : A yield area distribution similar to that of the reference data is obtained when the Mohr–Coulomb material model is used in the numerical analysis of the concrete splitting tension, thus confirming the validity of the model. In the Mohr–Coulomb material model, nonlinear resistance continues even after the maximum reaction force occurs. However, when the stress–strain curve material model is applied, at the moment the maximum reaction force occurs, the material yields and begins to be damaged. In addition, by applying the Mohr–Coulomb material model to the bending numerical-analysis model, the magnitude of stress in the tensile region from the initial stage exceeds the yield stress defined in the stress–strain curve. CONCLUSIONS : Based on a series of examples, the usability of the proposed concrete stress–strain curve and Mohr–Coulomb parameters is confirmed. However, to obtain numerical-analysis results that are consistent with the nonlinear behavior of actual structures, nonlinear testing of reinforced concrete structures shall be conducted and material models shall be improved.

Steel plate shear walls (SPSWs) have been recognized as an effective seismic-force resisting systems due to their excellent strength and stiffness characteristics. The infill steel plate in a SPSW is constrained by a boundary frame consisting of vertical and horizontal structural members. The main purpose of this study was to investigate deformation modes and hysteretic characteristics of steel plate shear walls (SPSWs) to consider the effects of their aspect ratios and width-to-thicness ratios. The finite element model (FEM) was establish in order to simulate cyclic responses of SPSWs which have the two-side clamped boundary condition and made of conventional steel grade. The stress distribution obtained from the FEA results demonstrated that the principal stresses on steel plate with large thickness-to-width ratio were more uniformly distributed along its horizontal cross section due to the formation of multiple struts.

Understanding the behavior of soil under cyclic loading conditions is essential for assessing its response to seismic events and potential liquefaction. This study investigates the effect of non-plastic fines content (FC) on excess pore pressure generation in medium-density sand-silt mixtures subjected to strain-controlled cyclic direct simple shear (CDSS) tests. The investigation is conducted by analyzing excess pore pressure (EPP) ratios and the number of cycles to liquefaction (Ncyc-liq) under varying shear strain levels and FC values. The study uses Jumunjin sand and silica silt with FC values ranging from 0% to 40% and shear strain levels of 0.1%, 0.2%, 0.5%, and 1.0%. The findings indicate that the EPP ratio increases rapidly during loading cycles, with higher shear strain levels generating more EPP and requiring fewer cycles to reach liquefaction. At 1.0% and 0.5% shear strain levels, FC has a limited effect on Ncyc-liq. However, at a lower shear strain level of 0.2%, increasing FC from 0 to 10% reduces Ncyc-liq from 42 to 27, and as FC increases further, Ncyc-liq also increases. In summary, this study provides valuable insights into the behavior of soil under cyclic loading conditions. It highlights the significance of shear strain levels and FC values in excess pore pressure generation and liquefaction susceptibility.

PURPOSES : This study was conducted to investigate the stress distribution and resulting effects in the joint between CRCP and JCP when temperature deformation occurs. METHODS : The tie bars, CRCP and JCP pavements, and lean concrete base were created as three-dimensional finite element models using ABAQUS, a general-purpose finite element analysis program. Contact stress analysis was performed between rebar and JCP and between JCP and lean concrete base layer. In the section where stress concentration occurred, the degree of damage was estimated using the CDP model. RESULTS : Since the domestic CRCP does not have a separation layer between the base layer and the surface layer, it was found that when connected to a JCP where the base layer and the surface layer are completely separated, stress concentration occurs around the tie bar at the connection point. Analysis results using the CDP model showed that 25 to 32 mm around the reinforcing bar exceeded the elastic range of concrete. CONCLUSIONS : At the point where CRCP and JCP are connected, local stress concentration is inevitable because the friction and bonding conditions with the base layer and the degree of curling deformation restraint by CRCP rebars are different, and design improvement is expected through life cycle cost and long-term measurement analysis.

This study reports an experimental and analytical exploration of concrete columns laterally confined with Fe-based shape-memory alloy (Fe-SMA) spirals. For performing experiments, Fe-SMA rebars with a 4% prestrain and diameter of 10 mm were fabricated and concrete columns with internal Fe-SMA spiral reinforcement were constructed with a diameter of 200 mm and height of 600 mm. An acrylic bar with an attached strain gauge was embedded in the center of the specimen to measure local strains. Experimental variables encompassed the Fe-SMA spiral reinforcement, spacing, and activation temperature. Uniaxial compression tests were conducted after applying active confinement to the concrete columns through electrical-resistance heating. Notably, as the Fe-SMA spiral spacing decreased, the local failure zone length and compressive fracture energy of the prepared specimens increased. Additionally, a model incorporating compressive fracture energy was proposed to predict the stress–strain behavior of the. This model, accounting for active and passive confinement effects, demonstrated accurate predictions for the experimental results of this study as well as for previously reported results.

The EV electric vehicle market is growing rapidly worldwide. Magnet fixing technology is important for mass production of driving motors, a key part of electric vehicles. The magnet fixing method was carried out by the PAM (Polyamide molding) method. This study conducted the injection of rotor core magnet PA of EV traction motor and is a study on the amount of rotor core deformation. In this study, the change in the outer diameter of the product after injection and the non-molding phenomenon were tested. An injection mold was made and the results and phenomena of product deformation types are discussed.

The most comprehensive and particularly reliable method for non-destructively measuring the residual stress of the surface layer of metals is the sin method. When X-rays were used the relationship of sin measured on the surface layer of the processing metal did not show linearity when the sin method was used. In this case, since the effective penetration depth changes according to the changing direction of the incident X-ray,  becomes a sin function. Since  cannot be used as a constant, the relationship in sin cannot be linear. Therefore, in this paper, the orthogonal function method according to Warren’s diffraction theory and the basic profile of normal distribution were synthesized, and the X-ray diffraction profile was calculated and reviewed when there was a linear strain (stress) gradient on the surface. When there is a strain gradient, the X-ray diffraction profile becomes asymmetric, and as a result, the peak position, the position of half-maximum, and the centroid position show different values. The difference between the peak position and the centroid position appeared more clearly as the strain (stress) gradient became larger, and the basic profile width was smaller. The weighted average strain enables stress analysis when there is a strain (stress) gradient, based on the strain value corresponding to the centroid position of the diffracted X-rays. At the 1/5 max height of X-ray diffraction, the position where the diffracted X-ray is divided into two by drawing a straight line parallel to the background, corresponds approximately to the centroid position.

A fixed-point iteration is proposed to integrate the stress and state variables in the incremental analysis of plastic deformation. The Conventional Newton–Raphson method requires a second-order derivative of the yield function to generate a complicated code, and the convergence cannot be guaranteed beforehand. The proposed fixed-point iteration does not require a second-order derivative of the yield function, and convergence is ensured for a given strain increment. The fixed-point iteration is easier to implement, and the computational time is shortened compared with the Newton–Raphson method. The plane-stress condition is considered for the biaxial loading conditions to confirm the convergence of the fixed-point iteration. 3-dimensional tensile specimen is considered to compare the computational times in the ABAQUS/explicit finite element analysis.

For a plastic diffusion lens to uniformly diffuse light, it is important to minimize deformation that may occur during injection molding and to minimize deformation. It is essential to control the injection molding condition precisely. In addition, as the number of meshes increases, there is a limitation in that the time required for analysis increases. Therefore, We applied machine learning algorithms for faster and more precise control of molding conditions. This study attempts to predict the deformation of a plastic diffusion lens using the Decision Tree regression algorithm. As the variables of injection molding, melt temperature, packing pressure, packing time, and ram speed were set as variables, and the dependent variable was set as the deformation value. A total of 256 injection molding analyses were conducted. We evaluated the prediction model's performance after learning the Decision Tree regression model based on the result data of 256 injection molding analyses. In addition, We confirmed the prediction model's reliability by comparing the injection molding analysis results.

국내의 서비스 수준 지진(SLE)과 최대 고려 지진(MCE)의 두 RC 건물 구조물의 실험 및 해석 결과에서 얻은 탄성 및 비탄성 응답은 비틀림에 대한 전단 및 비틀림 거동에서 저항 메커니즘의 특성을 연구하는데 사용될 수 있다. 불균형 구조의 특성 연구에서는 전단력 및 비틀림 모멘트에 대한 병진 변형 및 비틀림 변형의 상호 작용 효과를 나타내는 방정식이 제안하였다. 탄성과 비탄성 거동에서 힘과 변형 사이에 상관 관계 유무가 다르기 때문에 증분 전단력과 증분 비틀림 모멘트를 최대 벽 프레임 변형을 중심으로 항복, 제하 및 재 하중 단계로 구분하여 해당 증분 변형 및 증분 비틀림 변형 측면에서 해석을 수행하였다. 두 가지 주요 지배 모드의 탄성 조합에서 병 진 변형은 주로 전단력에 기여하는 반면 비틀림 변형은 전체 비틀림 모멘트에 크게 기여한다. 그러나 비탄성 응답에서는 증분 병진 변 형이 증분 전단력과 증분 비틀림 모멘트 모두에 기여하게 된다. 따라서 주어진 방정식을 이용하여 비탄성 응답에서 비틀림의 편심 감 소, 비틀림 강성 저하 및 겉보기 에너지 생성과 같은 모든 현상들을 설명하였다.

본 논문은 연구자의 박사 학위 논문 중 1장과 3장 2절을 중심으로 발췌 및 번역한 것으로, 리 스트(Franz Liszt, 1811-1886)의 B단조 소나타에서 나타나는 십자가 모티브(cross motive)의 주제 적, 표현적 변형에 초점을 맞추고, 모티브의 변형을 통해 생성되는 내러티브적 해석을 제시하는데 그 목적이 있다. 십자가 모티브는 그레고리안 성가 ≪신앙의 십자가≫(Crux Fidelis)에서 유래한 선율적 모티브로, 리스트의 작품에서는 기독교에서의 구원을 의미하거나 그의 신앙심이 표현되는 맥락에서 주로 사용된다. 리스트의 소나타에서는 다섯 개의 모토가 주제적 발전의 기초적 아이디 어를 제공하며, 그 중 네 번째 모토인 십자가 모티브는 5번에 걸쳐 등장하며 주제적 변형뿐만 아 니라 표현적 변형의 과정을 거친다. 본 논문은 음악이 진행됨에 따라 음악적 아이디어가 정서적 상태의 변화를 경험할 수 있음을 의미하는 클라인(Michael Klein)의 용어 ‘표현적 변형’(expressive transformation)과 해튼(Robert Hatten)의 ‘표현적 장르’(expressvie genre)의 개념을 연구의 출발 점으로 삼는다. 제시부의 2주제 영역에서의 십자가 모티브의 첫 등장은 화려하고 장대한 반주와 상승하는 십 자가 모티브 선율의 조합으로 인해 D장조에서 종교적인 장엄함을 드러낸다. 반면 발전부에서 제 시된 십자가 모티브는 단조성의 선율, 낮은 음역, 불협화음, 강한 다이내믹으로 인해 고통스러운 모습으로 변모하다. 이는 십자가 모티브의 정서적 상태가 비극적으로 변형되었음을 보여준다. 재 현부와 코다에서 등장하는 십자가 모티브는 이전의 종교성, 장엄함, 영웅적 당당함, 승리를 다시 회복하며 기쁨과 환희에 찬 절정의 감정적 상태를 보여준다. 이와 같은 십자가 모티브의 변형은 ‘비극과 고통에서 다시 쟁취해 낸 승리’의 내러티브로 표현될 수 있다. 본 논문은 이러한 내러티브 를 제시하는 과정에서 헐리우드 영화 ≪레버넌트≫의 정서 구조와 십자가 모티브의 정서적 흐름 에서 상호텍스트성(intertextuality)을 발견했고, 상호텍스트적 맥락의 적용을 통해 본 논문이 제시 하는 해석학적 분석에 대한 접근성과 흥미를 높이고자 했다.