Engineering design primarily focuses on product improvement through enhancing existing functionalities, integrating features, or adding new capabilities. In other words, it can be said that more design(adaptive design) changes to existing products based on benchmarking with competing products, differentiation strategies, changes in customer needs, etc. are actually performed rather than developing new products that did not exist before. Especially in the case of custom production, such as ships or buildings, a significant portion of actual design work involves modifying and adjusting past performance data according to the current customer's requirements. Therefore, design methods should be developed in a way that effectively supports these processes. Therefore, in this study, as QFD (Quality Function Deployment) ‘analysis of existing products’ and ‘creation of new alternatives’ is supported in Marine Concept Design with AHP (Analytic Hierarchy Process) techniques such as ‘Value Evaluation in Analysis Work’ and ‘Design Alternative Evaluation’, as a result, basic research was conducted on whether it could be used as a tool to effectively support the flow of the design process.
Engineering design involves making numerous decisions as the design process. These decisions can be broadly categorized into selection decisions and compromise decisions. The outcomes of these decisions heavily depend on the designer's intentions, highlighting the need to systematically and accurately incorporate the designer's intentions. The Analytic Hierarchy Process (AHP) is a design technique that systematically reflects the designer's intentions by hierarchically analyzing and evaluating ambiguous decision problems. Therefore, in this study, effective optimal structure designs that maximally reflect the designer's intentions were confirmed by introducing AHP (Analytic Hierarchy Process) and Neural Network into the foundational decision-making process of engineering design.
One major concern of Seoul City is the premature failure occurrence such as fatigue cracking and rutting in the pavement. Due to the acceleration at intersections and low vehicle speed at bus stops that cause higher shear and critical strain on the pavement. Because of this, there is a need to develop a new mixture that can withstand bus stop and intersection traffic while preventing premature failure. In this study, a high modulus asphalt mixture was adapted and developed to address the cracking and rutting concerns at bus stops and intersections of Seoul City. Indirect tensile (IDT) and beam fatigue testing were conducted to determine the fatigue performance of the high modulus asphalt mixture (HMB). In addition, the behaviour of the HMB considering loading speed and temperature were investigated using the IDT dynamic modulus test. It was found that the HMB performs 3 and 1.5 times better compared to conventional asphalt using IDT and beam fatigue test respectively. Moreover, it was observed that modulus value of HMB is two times better at low frequency (high temperature) compared to conventional asphalt. The dynamic modulus value of the HMB was then used as input for bus stop and intersection scenario analyses. It was found that HMB can reduce the total thickness of the pavement around 4 to 6cm compared to the conventional asphalt. It can be concluded that because of the better fatigue and rutting performance and high modulus value of HMB at low frequency, it can perform better in bus stops and intersections. It is recommended to conduct field construction to further evaluate the performance of HMB asphalt mixtures in the field.
This paper describes a preliminary ship design optimal design method in the process of hull form design. In the deterministic approach, an interdisciplinary ship design method integrates principal dimension decisions and hull form variations in the preliminary ship design stage. Integrated ship design, as presented in this paper, has the distinctive feature that these parameters are evaluated simultaneously. Conversely, in sequential design, which is based on the traditional preliminary ship design process, hull form designs and principal dimension decisions are determined separately and sequentially. The current study adopts the first method to enhance the design quality in the early design stage.
In product development, different divisions and businesses often have heterogeneous CAD/CAE systems and methods for expressing product data, and addressing this heterogeneity creates additional costs and causes longer development periods. To ensure successful collaboration in the design process, it is therefore imperative that different CAD, CAE, and other related systems be managed in an organic and integrated manner from the initial stages of product development. Therefore, this study suggests an integrated CAD/CAE system including optimal design in a more effective and integrated manner but also to support interfacing and the collective use of design and analysis tools. To validate the proposed method, a stiffened plate example is taken as an example. It is found that the proposed method could overcome the bottleneck of CAD and CAE such as transferability of data, though CATIA and ANSYS are used at the moment.
This study was conducted to explore if the ground beetle (Coleoptera: Carabidae) can be used as an indicator classifying habitat types. Thirteen land use types were selected as survey sites in Jeonju. Ground beetles were collected by 3 pitfall traps (15 cm diameter) for each site from June 20 to September 22, 2008. Pitfall traps were replaced at one month interval. Total 919 ground beetles of 31 species belonging to 17 genera were collected. Land use types were classified and ordinated by two-way indicator species analysis and detrended correspondence analysis. Land use types were classified and ordinated into two major groups, forest and non-forest, by Synuchus nitidus and Dolichus halensis. Two major groups were subdivided into 4 end groups; forest, riverside, upland and other sites. Other sites group including 4 sites; levee, public garden, outfield and manufacturing area were not coincided with land use types. Nevertheless, ground beetles appear to be used as indicators of habitat types.
고강도 콘크리트 보의 극한상태의 거동을 강도에 따라 연구하였다. 13개의 보를 해석하고 그 결과를 제시하였다. 변수는 콘크리트의 압축강도로 범위는 57~184 MPa이며, 횡방향 철근비로 범위는0.35~1.49%이다. 실험에서 측정한 극한 비틀림 강도를 본 논문에서 제안한 값과 ACI 기준에 따른 값을 비교하였다. 그 결과 본 논문에서 제안한 이론에 의한 극한 비틀림 강도가 ACI 기준에 따른 값보다 더 좋은 결과를 보였다.