• 한국해양공학회지
• /
• 제36권2호
• /
• pp.132-142
• /
• 2022

We investigate the performance of multi-body wave energy converters (WECs). This investigation considers multiple scattering of water waves by the buoys of a WEC under the generalized mode approach. Predominantly, the effect of a WEC's configuration on its energy extraction is studied in this research. First, single-row terminator and single-column attenuator arrays of vertical cylinders have been studied. The performance of these attenuator arrays shows that the wall effect induced by the periodic buoys influences the wave propagation and energy extraction in these WECs. Further studies show that a single-row terminator array of vertical cylinders performs better than the corresponding single-column attenuator array. Subsequently, multi-row terminator arrays of vertical cylinders are investigated by conducting a parametric study. This parametric study shows that the hydrodynamic property of three resonance phenomena makes energy extraction efficiency drop down, and the magnitude of energy extracted oscillates between the resonance points in these WECs. Finally, a 4×8 terminator array of vertical cylinders is studied to determine the effect of various d_x (x-directional distance between adjacent rows) within this WEC on its performance. In particular, this study enforces at least two equal d_x values within the 4×8 terminator array of vertical cylinders. It shows that a small value of this d_x leads to better energy extraction efficiency in some of these various d_x arrays than that of a corresponding regular array with the same d_x.

• Steel and Composite Structures
• /
• 제43권1호
• /
• pp.107-116
• /
• 2022

This paper presents results of numerical studies completed on unreinforced and doubler plate reinforced Elliptical Hollow Section (EHS) T-joints subjected to axial compressive loading on the brace member. Non-linear finite element (FE) models were developed using the finite element code, ABAQUS. Available test data in literature was used to validate the FE models. Subsequently, a parametric study was carried out to investigate the effects of various geometrical parameters of main members and reinforcement plates on the ultimate capacity of reinforced EHS T-joints. The parametric study found that the reinforcing plate significantly increases the ultimate capacity of EHS T-joints up to twice the capacity of the corresponding unreinforced joint. The thickness and length of the reinforcing plate have a positive effect on the ultimate capacity of Type 1 joints. This study, however, found that the capacity of Type 1 orientation is not dependent on the brace-to-chord diameter ratio. As for type 2 orientations, the thickness and length of the reinforcement have a minimal effect on the ultimate capacity. A new design method is introduced to predict the capacity of the reinforced EHS T-joints Type 1 and 2 based on the multiple linear regression analyses.

• Structural Engineering and Mechanics
• /
• 제89권1호
• /
• pp.61-75
• /
• 2024

Strengthening of hollow structural sections using through-bolts is a cost-effective and straightforward approach. It's a versatile method that can be applied during both design and service phases, serving as a non-disruptive and budget-friendly retrofitting solution. Existing research on axially loaded hollow sections T-joints has demonstrated that this technique can amplify the joint strength by 50%, where single bolt could enhance the strength of the joint by 35%. However, there's a gap in understanding their use for K-joints. As the behavior of K-joints is more complex, and they are widely existent in structures, this study aims to bridge that gap by conducting comprehensive parametric study using finite element analysis. Numerical investigation was conducted to evaluate the effect of through bolts on K-joints focusing on using single through bolt to achieve most of the strengthening effect. A full-scale parametric model was developed to investigate the effect of various geometric parameters of the joint. This study concluded the existence of optimal bolt location to achieve the highest strength gain for the joint. Moreover, a rigorous statistical analysis was conducted on the data to propose design equations to predict optimal bolt location and the corresponding strength gain implementing the verified by finite element models.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
• /
• pp.891-896
• /
• 2001

As composite materials, the addition of steel fiber in concrete significantly improves the engineering properties of structural members, notably shear strength and ductility, In this study, shear capacity evaluation method according to steel fiber contents was proposed from the literature surveys and member tests. For this, previously proposed five shear strength equation were examined and evaluated by maximum shear strength and shear capacity ratio. From the parametric study and regression analysis, following conclusion can be made; the maximum shear strength of steel fiber reinforced column will be estimated by relative shear capacity ratio.

• Journal of Welding and Joining
• /
• 제5권4호
• /
• pp.47-53
• /
• 1987

The purpose of this study is to reexamine our test method in the light ofstatistical methods for data interpretation. Our trial to apply Plackett-Burman statistical model in multifactorial welding experiments shows that is saves much time and cost and extracts very accurate results. In this study, the parametric effects of bead shape on pulse MIG process in Cu-Ni alloy are investigated for verifying our trial.

• 한국전산구조공학회논문집
• /
• 제28권4호
• /
• pp.393-400
• /
• 2015

본 연구는 기획단계, 설계단계 및 시공단계에서 사용가능한, 모듈러 강교량 상부구조 정보모델 생성의 효율성을 향상하기 위하여, 파라메트릭 모델링(parametric modeling)을 통해 상부모듈을 생성하고 이들을 조합할 수 있는 방안을 제시하였다. 파라메트릭 모델링을 적용하기 위한 요소 도출을 위하여 상부구조 구성요소 분류를 수행하였고, 분류된 요소를 결합 조건에 따라 13개의 종으로 구분하였다. 또한 모듈러 강교량 공장 제작 단위인 상부모듈의 조합을 통해 안정적인 상부구조 생성을 위한 세 가지 조합조건을 도출하였다. 파라메트릭 모델링을 통한 상부모듈 생성 시 구성요소 형상에 조합조건을 반영하는 변수를 도출하였다. 이를 본 연구에서 개발한 Building Information Model(BIM) 소프트웨어기반의 생성 인터페이스를 활용하여 타입과 변수에 따른 상부모듈 구성요소들을 생성하였다. 이때 생성된 상부모듈에는 상부구조로 조합하기 위한 정보를 반영하였으며, 이를 검증하기 위하여 Industry Foundation Classes(IFC) 기반의 정보모델을 생성하고, 반영한 속성정보를 확인함으로써 상부구조 생성에 활용할 수 있음을 확인하였다.

• 한국의류산업학회지
• /
• 제25권2호
• /
• pp.139-152
• /
• 2023

Despite efforts to apply 3D print (3DP) technology in the field of fashion and endless discussions about the possibility of future development, in reality, it is difficult to utilize 3DP technology in fashion for reasons related to material, technology, and cost constraints. The purpose of this study was to supplement the limitations of 3DP technology in order to promote its utilization in fashion and simultaneously find a solution to achieve aesthetic satisfaction in the design method. Specifically, through the development of fashion products with a 3DP polymer-fabric structure to which the parametric design methodology has been applied, this study explored the possibility of practical application and proposes a new 3DP fashion design method. The 3DP polymer-fabric developed as a result of the research was stably adhered to the fabric. Additionally, the study confirmed the possibility of making 3DP clothes that are amenable to the wearer's activities, as it was verified that cutting and sewing tailored to the human body's curvature and structure can be performed. The design process using the 3DP polymer-fabric presented in this study is meaningful in that it suggests a solution to complement the limitations of modern technology in connection with designers' creativity. Moreover, the design process presented in this study is expected to contribute to the commercialization and generalization of 3DP by providing practical help to allow fashion experts to utilize 3DP technology.

• 대한토목학회논문집
• /
• 제30권4A호
• /
• pp.361-373
• /
• 2010

일체식 교대 교량은 신축이음장치 및 교좌장치가 없이 하부구조와 상부구조를 일체화한 구조형식으로, 상부구조의 온도변화 등에 의해 발생하는 변형을 교대하부에 배치한 파일의 휨 변형을 통하여 해소하는 교량형식이다. 본 연구에서는 지반-파일 상호관계 모형화 방법에 따른 일체식 교대 교량의 거동비교를 통하여 합리적인 모형화 방법을 제시하고, 매개변수 해석을 통하여 일체식 교대 교량의 상부구조 및 파일의 거동특성을 평가하였다. 매개변수 해석을 위해 파일 관입부 지반조건, 교대 높이, 파일 길이를 매개변수로 선정하였고, 지반-파일 및 온도변화-교대배면토압 상호관계를 고려하여 구조해석을 수행하였다. 지반-파일 상호관계 모형화에 따른 일체식 교대 교량의 거동을 비교한 결과 탄성지반스프링 방법이 일체식 교대 교량의 거동을 평가하는데 보다 합리적인 것으로 판단된다. 일체식 교대 교량의 매개변수 해석 결과 파일 관입부 지반강성이 증가할수록 상부구조에 작용하는 모멘트가 증가하고 파일의 변위가 감소하는 경향을 보였다. 또한, 교대의 높이가 증가할수록 교대배면토압이 증가하고 이것이 상부구조 및 파일의 거동에 영향을 주었음을 확인하였으며, 파일의 길이가 증가할수록 일체식 교대 교량이 유연한 거동을 보임을 확인하였다.

• 한국터널지하공간학회 논문집
• /
• 제16권5호
• /
• pp.487-495
• /
• 2014

본 연구에서는 주방식 지하구조물에서 지보재 설계를 위한 매개변수 연구를 수행하였다. 지보재 설계에 앞서 설계에 필요한 암주와 공간의 형상별 천단변위, 최대 주응력, 소성영역에 대한 해석을 수행하였다. 해석에 사용할 매개변수를 최적화 하기위해 주방식 지하구조물의 대상 심도와 지반 조건은 기존 지하철 정거장 건설 사례를 분석하여 결정하였으며 지하공간의 활용 목적에 따라 암주의 형상과 공간의 형상을 설정하여 총 180가지의 경우를 선택하였다. 매개변수 해석을 통해 획득한 결과는 향후 지하구조의 안정성과 공간 활용성, 시공장비의 적용성을 고려하여 지보재 설계와 설치 여부를 판단할 수 있는 근거자료로 활용될 수 있을 것으로 판단된다.

• Computers and Concrete
• /
• 제20권4호
• /
• pp.391-407
• /
• 2017

Fiber reinforced polymer (FRP) bars have been recently used to reinforce concrete members in flexure due to their high tensile strength and especially in corrosive environments to improve the durability of concrete structures. However, FRPs have a low modulus of elasticity and a linear elastic behavior up to rupture, thus reinforced concrete (RC) components with such materials would exhibit a less ductility in comparison with steel reinforcement at the similar members. There were several studies showed the behavior of concrete beams with the hybrid combination of steel and FRP longitudinal reinforcement by adopting the experimental and numerical programs. The current study presents a numerical and analytical investigation based on the data of previous researches. Three-dimensional (3D) finite element (FE) models of beams by using ANSYS are built and investigated. In addition, this study also discusses on the design methods for hybrid FRP-steel beams in terms of ultimate moment capacity, load-deflection response, crack width, and ductility. The effects of the reinforcement ratio, concrete compressive strength, arrangement of reinforcement, and the length of FRP bars on the mechanical performance of hybrid beams are considered as a parametric study by means of FE method. The results obtained from this study are compared and verified with the experimental and numerical data of the literature. This study provides insight into the mechanical performances of hybrid FRP-steel RC beams, builds the reliable FE models which can be used to predict the structural behavior of hybrid RC beams, offers a rational design method together with an useful database to evaluate the ductility for concrete beams with the combination of FRP and steel reinforcement, and motivates the further development in the future research by applying parametric study.