Detailed Design Stage Research Articles

An Infrastructure’s emissions assessment tool: AMICO - Account Method of Infrastructures embodied CarbOn

Abstract In 2013, the UK Infrastructure Carbon Review report highlighted how the infrastructure sector contributed to the national total emissions and, therefore, had a key role in contributing to the national reduction, adopting targeted strategies to reduce them. The main objective of AMICO’s research project: “Account Method of Infrastructures embodied CarbOn”, is the development of a tool for the analysis and parametric evaluation of carbon emissions (Embodied Carbon, EC) and energy resource requirements (Embodied Energy, EE) related to the design and construction of infrastructures (railway tunnels, bridges, highways …) AMICO tool is designed to be used for tendering, contract start-up and construction of infrastructure by Webuild Group (Italian Joint Stock Company) as part of a research project funded by MIMIT - Ministry of Business and Made in Italy, with the scientific support of the Politecnico di Torino (Department of Architecture and Design). AMICO aims to assess potential impacts in terms of greenhouse gas emissions (GHG) and potential primary energy resource needs over the infrastructure life cycle and at different design process stages, allowing designers and constructors to evaluate decarbonisation in their choices. AMICO is currently organised into two calculation models: 1. An Excel spreadsheet file, divided into worksheets containing algorithms for accounting of EC and EE, organised into two usage models: Basic, which will be used for tenders and the early design stage, and Advanced, which will be used in the detailed design or construction stage. 2. A code for the BIM environment that accounts for impacts (EE and EC) related to infrastructure systems (as defined by UNICLASS) combined and concurrently with design in the BIM environment (this section is not the focus of this paper). An innovation aspect is sharing a database of environmental data about materials and processes (transportation, construction, demolition) directly related to the Bill of Quantity without using Life Cycle Assessment software. The database will be integrated into the Datalake to speed up and optimise infrastructure design and construction work. You can set the database to the location of the work. Through data digitisation, AMICO is designed to be as automated, easy to fill in, and intuitive as possible.

Design frameworks for ventilative cooling: Perceptions from building design practitioners in Ireland and the United Kingdom

The global increase in building cooling demands poses a challenge for designers striving for net zero energy consumption. The prevalent use of mechanical cooling underscores the necessity for designers to consider Ventilative Cooling as a viable alternative in the early stages of building design. This paper presents findings from an exploratory survey and semi-structured interviews of industry experts in Ireland and the United Kingdom about their design processes and experienced-based approaches to designing Ventilative Cooling. The findings suggest that the pre-design stage has the same influence for promoting ventilative cooling strategies as the schematic and detailed design stages for practitioners, yet limited impactful decision making occurs at this stage. Over 70 % of the survey respondents reported satisfaction with current Ventilative Cooling tools used in building design. Only 8 % of architects use a ventilative cooling tool, while engineers always do, showing that separate design advice is needed for architects and engineers. The interview findings indicate that early-stage design interventions for Ventilative Cooling can be improved if there was more empirical evidence of how strategies perform available as design guidance in ventilative cooling design guidelines. Additionally, engineers highlighted that post-occupancy evaluation and site monitoring of existing buildings are crucial stages of further research that can identify the effectiveness of Ventilative Cooling design decisions. In their building designs, the practitioners reported a need for preparedness to assess resilience to extreme future climate events such as heat waves. Effective communication between industry and academic research can help improve the built environment industry's future readiness.

Innovative Thinking Approach in Designing Teaching Materials for Ilm Badi Course: A Comprehensive Framework for Enhancing Students' Writing Skills

Students face several challenges in learning Ilm Badi, including difficulty understanding learning objectives, a lack of comprehension regarding the classification in Ilm Badi materials, insufficient visual stimuli in teaching materials, and challenges in generating new sentences. These issues indicate a mismatch between theoretical understanding and practical language skills. Therefore, this study aims to design teaching materials for Ilm Badi with an innovative thinking approach to stimulate students' writing creativity. The research method employed is Research and Development (R&D), integrating the instructional material design procedure by Sa'ud with the ADDIE model. Data were collected through interviews, observations, and questionnaires. The results indicate that the innovative thinking approach is relevant in strengthening creative thinking processes in general and supports the teaching of Ilm Badi with a more progressive and contextual approach. The teaching materials produced through detailed design stages involve composing content in Arabic and Indonesian, utilizing additional visualizations, and designing exercises to encourage students' innovative thinking abilities. The teaching materials design process includes collaboration with relevant experts. It undergoes expert assessments, resulting in teaching materials that meet standards for use in Ilm Badi learning, emphasizing innovative thinking. Further studies are necessary to test the designed teaching materials' effectiveness empirically.

A Service Blueprint Approach in Ship Building Activity Mapping

In the evolving landscape of shipbuilding, the confluence of innovative methodologies and advanced technologies is reshaping paradigms in ship design and production. The industry's quest for multidisciplinary methods that elaborate representing diverse ship building activities and boost efficiency in managing these activities has unveiled the potential of the service blueprint, a tool used in service design, which addresses design of activities and determining who does what activities when in collaboration with whom. Our proposition centres on the structured activity mapping representation, a novel activity map that utilizes service blueprint with detailed description of activities with rich and structured representation of context. The framework offers a comprehensive perspective, illuminating intricate processes such as concept design, detailed design and production stages as well as service and operation stages. This mapping would ensure alignment of each activity with overarching project objectives, encapsulating values, interactions, collaborations. This paper illustrates the approach of service blueprint in representing ship building activities with discussion on improvement potential of current activity mapping through the service blueprint approach as being conducted in the SEUS EU Horizon project.

A case study on the stability of a big underground powerhouse cavern cut by an interlayer shear zone in the China Baihetan hydropower plant

AbstractThe big underground powerhouse cavern of the China Baihetan hydropower plant is 438 m long, 34 m wide, and 88.7 m high. It is cut by a weak interlayer shear zone and its high sidewall poses a huge stability problem. This paper reports our successful solution of this problem through numerical simulations and a replacement‐tunnel scheme in the detailed design stage and close site monitoring in the excavation stage. Particularly, in the detail design stage, mechanical parameters of the shear zone were carefully determined through laboratory experiments and site tests. Then, deformation of the surrounding rocks and the shear zone under high in situ stress conditions was predicted using 3 Dimensional Distinct Element Code (3DEC). Subsequently, a replacement‐tunnel scheme was proposed for the treatment on the shear zone to prevent severe unloading relaxation of surrounding rocks. In the construction period, excavation responses were closely monitored on deformations of surrounding rocks and the shear zone. The effect of local cracking in the replacement tunnels on sidewall stability was evaluated using the strength reduction method. These monitoring results were compared with the predicted numerical simulation in the detailed design stage. It is found that the shear zone greatly modified the deformation mode of the cavern surrounding rocks. Without any treatment, rock mass deformation on the downstream sidewall was larger than 125 mm and the shearing deformation of the shear zone was 60–70 mm. These preset replacement tunnels can reduce not only the unloading and relaxation of rock masses but also the maximum shearing deformation of the shear zone by 10–20 mm. The predictions by numerical simulation were in good agreement with the monitoring results. The proposed tunnel‐replacement scheme can not only restrain the shear zone deformation but also enhance the safety of surrounding rocks and concrete tunnels. This design procedure offers a good reference for interaction between a big underground cavern and a weak layer zone in the future.

The Intelligent Layout of the Ship Piping System Based on the Optimization Algorithm

The ship piping layout is one of the essential tasks in the detailed design stage of a ship. Traditional manual expert design has disadvantages such as low efficiency, reliance on experience, and subjective influence. Therefore, this paper systematically proposes an intelligent arrangement method for ships’ single, parallel, and branch pipelines. Firstly, the traditional genetic algorithm is improved and combined with the A* algorithm to solve the intelligent arrangement problem of a single pipeline in ships. Then, the parallel pipeline and branch pipeline are split into multiple single pipelines by combining with the connection point strategy to solve the arrangement problem of parallel pipeline and branch pipeline. Finally, the optimized A*-genetic algorithm proposed in this paper is compared with the A* algorithm, particle swarm algorithm, and the labyrinth-genetic algorithm used in previous research through simulation experiments. The results show that the A*-genetic algorithm of this paper is optimal in six indexes, including length, number of elbows, energy value, fitness value, number of optimal solutions, and average number of convergence generations, in the arrangement of the single pipeline. In solving the parallel pipeline and branch pipeline arrangement problems, the all-around performance of this paper’s algorithm is better than that of A*-genetic algorithm and maze–genetic algorithm, respectively. The A*-genetic algorithm of this paper considers the quality of pipeline arrangement and the solution’s efficiency. It verifies the adaptability and superiority of the algorithm for the intelligent arrangement of various types of pipelines in ship pipelines.

Designing and constructing of a laboratory scale concrete roof tile dryer

There are some problems with the drying process in the concrete tiles local industry, especially due to uncertain weather, where the drying process relies on sunlight. In addition, roof tile dryers have not yet hit the market. A laboratory-scale dryer is needed to develop a full-scale concrete roof tile dryer. This research aims to design and manufacture a laboratory-scale concrete tile dryer. The dryer will be used to investigate the characteristics of the concrete roof drying. The design was carried out using the Pahl and Beitz method, in three stages, namely planning, conceptual design, and detailed design. In the planning stage, a requirement list was stated, in the conceptual design stage, selected tools are determined for every sub-function, while in the detail design stage, shop drawings were produced. To produce a better distribution of air velocity and temperature, at this detailed design stage, a Solidworks CFD numerical analysis was used. The dimension of the drier is 1600 x 1100 x 1100 mm³, with a capacity of 60 - 180 kg, with air velocity of 3 m/s and variable temperature. The drying chamber consists of 3 layers. The heat source is LPG flame and electric heater. The fresh air is flown to the LPG burner, through a circulating fan into the drying chamber, where the concrete roof tiles are situated. The roof tile dryer was constructed and tested. The test results show that the air velocity at the top layer accorded with the CFD result, while in the second layer and third layer of the drying chamber, the air velocity was relatively small. The temperature in each layer of the drying chamber shows the same value, in this case, the temperature for each layer is 38°C, while the set point at the thermostat was 40°C. The relative humidity of the drying air was 21.7% while the ambient air relative humidity was 52%.

Safety Design of Uncontained Engine Rotor Failure for Civil Aircraft Primary Flight Control System

The safety design of uncontained engine rotor failure for civil aircraft primary flight control systems is more difficult than other airborne systems. This paper presents a safety design method that establishes a two-stage collision model inspection mechanism and introduces an automatic analysis algorithm in the process of comprehensive impact analysis of the cascade system. The method applies to the detailed design stage of civil aircraft systems. It can reduce the difficulty of the safety analysis process and improve the accuracy of the analysis results. The verification of a civil aircraft primary flight control system design shows that after using the safety design method, the time cost of the analysis process is significantly reduced, and the analysis results are more accurate, thereby reducing the difficulty of design changes.

Planning for a quieter environment in Hong Kong: Construction Noise Management Plan

Daytime construction noise is one of the most annoying noise problems according to the findings of a household opinion survey in Hong Kong. Normally detail construction methods and equipment involved for a project are only available in the detail design stage and sometimes even after tendering of a construction contract. Early consideration on the use of quieter construction methods and equipment before tendering are essential to ensure such methods/equipment would be adopted and hence a new construction noise impact assessment approach is proposed. Under the new approach only qualitative assessment, which includes the identification of the key noisy activities and the commitment of adopting quieter construction method/equipment, would be carried out in the early planning stage and then followed by the submission of a Construction Noise Management Plan (CNMP) before tendering. The CNMP should include quantitative assessment and the particular specifications in construction contracts for adopting the quieter construction methods/equipment. To further assist the project proponents in preparing CNMP, a new web-based platform called Web-CNMP has also been developed. This paper will outline control and management of construction noise in Hong Kong, the rationale and details of this new approach, Web-CNMP and explain how they can improve the noise environment.

Developing a multi-objective optimization model for improving building's environmental performance over the whole design process

This study is built upon two previous articles which focus on identifying the key design variables affecting the life-cycle environmental impacts in each design stage of the building design process. This research aims to investigate the trade-offs between embodied and operational impacts and explore potential reduction in the total environmental impacts of a building by varying the identified design variables in each stage of the design process. A multi-objective optimization model based on BIM and LCA integration has been developed to find out the design solution with the optimal trade-offs between the embodied and operational impacts and the option with the minimal environmental impacts. Applying the proposed model to a mid-rise residential building, the results showed that the design process has the potential to lower the environmental impacts of the building by approximately 47.6 %. Moreover, the potential for reducing carbon emissions is greater in the early design stages, with the potential to lower emissions by up to 32.5 %, compared to the lower emission reduction potential of approximately 7.5 % in the detailed and construction design stages. Furthermore, solutions aimed at addressing the trade-off between embodied and operational impacts were identified in each design stage. The study provides an insight into the understanding of how building design can be optimized to mitigate environmental impacts.

The GENEAP project: digitalising and automating planning of district heating and cooling

The Swiss Energy Strategy 2050 implies a transformation of the provision of thermal energy services (heating and cooling) to become CO2 neutral, district heating and cooling (DHC) are an important solution, which is technically challenging to design and whose implementation entails certain risks for investment. The GENEAP (Geospatial Analysis and Planning) project developed a software that applies automation and digitalisation to address this barrier and to apply scientific research to support the work of practitioners. The software Thermal Energy System Simulation Assistant (TESSA) increases reproducibility and decreases errors, and thereby reducing overall costs. We introduced innovative algorithms for modelling heat and cooling demand, thermal energy supplies, and the cost of thermal network technologies under different retrofit and climate change scenarios. We developed graph theory-based algorithms for computationally efficient routing of thermal network pipes. The goal of the GENEAP project was to validate the models and to establish how practitioners would find value in such a tool. Through workshops and interviews we established the need for digital tools due to the rapidly increasing need for new projects, the complexity and long time frames of projects, and the limited number of available experts to do this work. We found a gap between the high level energy strategy (Plan Directeur Energetique) and the detailed engineering design stage. In between these two stages we find the need for a flexible approach that can integrate cities and societies needs into the engineering design with non-energy requirements (e.g. political context, urban constraints and opportunities, etc).

Rekomendasi Rencana Anggaran Biaya dari Audit Keselamatan Jalan Tahap Detail Engineering Design (DED) pada Jalan Nasional Provinsi Jambi

From 2016 – 2018 in Jambi province there were 3,543 traffic accidents, with 1,085 deaths. What causes traffic accidents is caused by three factors, human factors themselves, vehicle factors and road infrastructure factors. To reduce the occurrence of traffic accidents, you can eliminate or reduce the causes of traffic accidents, such as improving the safe condition of road infrastructure. The aim of this research is to calculate recommendations for budget plans from the results of road safety audits at the detailed engineering design (DED) stage, totaling six detailed engineering design (DED) documents on Jambi province national roads. This research uses road safety audit guidelines Pd 03 – 2019 – B. From the results of the analysis, the percentage between the safety cost recommendation results compared to the construction cost design (owner estimate) at DED 1 = 6.17%, DED 2 = 0.93%, DED 3 = 16.13%, DED 4 = 7.33%, DED 5 = 0.75% and DED 6 = 8.83% and the combined percentage obtained is 7.05%. Thus, a detailed engineering design (DED) still requires attention in producing a detailed engineering design (DED) that is oriented towards road safety and the costs of physical implementation of the results of road safety recommendations.

CDTC: Automatically establishing the trace links between class diagrams in design phase and source code

AbstractContextThe UML class diagram is commonly used to model functional structures and software code structures in both the preliminary and detailed design stages. And the abstraction level of UML class diagrams is usually higher than that of source code. Usually, there is a lack of trace links between these class diagrams and the source code, which may cause difficulties in understanding the source code, and affect the software evolution and maintenance.ObjectiveThe main goal of this article is to establish the trace links between highly abstracted UML class diagrams in the design phase and source code, and eventually help practitioners better understand source code.MethodWe propose an approach for the automated trace link establishment between UML class diagrams in the design phase and source code. To address the problem of abstraction level gap between them, we extend the UML class diagram by mining the synonymous phrases of class names and deducing the latent missing relationships between classes from multiple design documents. Then we build the trace links with a two‐phase approach including initial construction with fuzzy matching and further optimization by class relationship inference.ResultsExperiments on five open‐source projects show that the recalls of our approach are over 94%, and the F2‐scores are over 88%, with the gains of 30% to 60% than the four baselines.ConclusionOur work can be a reference for establishing the initial trace links between highly‐abstracted UML class diagrams and source code. Towards the higher abstraction of design diagrams, we extend UML class diagrams with the statistical analysis on multiple design documents. To guarantee the quality of trace links, we design a two‐phase approach by obtaining the “full but not good enough” trace links and filtering the “probably wrong” links. Experiments show that the main techniques of our approach behave as important role for tracing between high‐level class diagrams and source code.

Evaluation of floating wind turbine substructure designs by using long-term dynamic optimization

The substructure design plays an important role in the capital expenditure as well as the dynamic performance of floating wind turbines (FWTs). To determine the most cost-effective hull shape and mooring configuration from various design concepts, this paper proposes an evaluation methodology based on long-term dynamic optimization. To make the long-term dynamic performance assessment computationally affordable in the iterative optimization process, the FWT responses are approximated by a Kriging surrogate model, which is established via regression analysis between representative met-ocean parameters and the corresponding short-term responses. The short-term responses in stochastic wind and waves are simulated by an efficient reduced-order model (ROM) with eight degrees of freedom (DoFs). The Kriging model is employed to derive the long-term performance indicators, e.g. the lifetime accumulative fatigue damage at tower base and fairleads, the peak platform motion and nacelle acceleration. The model effectiveness is confirmed by the verification campaign against OpenFAST. Afterwards, this model is implemented into a multi-objective optimization framework that aims to find out the Pareto optimal designs that have the best trade-off between long-term dynamic performance and manufacturing cost. The NSGA-II algorithm is adopted to explore the substructure design space, with the consideration of constraints related to the inherent properties as well as the dynamic performance of structures. This methodology is applied to two typical semi-submersible FWTs: the Y-shaped and the square-shaped concept. By comparing their Pareto fronts, it is found that the square-shaped semi-submersible is expected to be a more favourable substructure for our case study. Under the same level of manufacturing cost, the tower base fatigue of square-shaped concept is mostly 30%–50% lower than that of the Y-shaped. Hydrodynamics is the main cause of the fatigue difference between the two concepts. This work provides a decision basis on which FWT substructure design is employed as input to the detail design stage.

A Method for Backward Failure Propagation in Conceptual System Design

The increased complexity of modern system designs and demands for quicker time to market have made safety-related verification and validation of such systems more challenging. Incorporating safety and risk considerations at the early stages of design is one way to acquire a more robust initial design for novel systems. Inductive fault analysis has its significance at final stages of design, e.g., verification and validation. However, to preclude certain system failure states—especially for the systems with high failure consequences, a designer would innately prefer to trace back and remedy the causes of failure, as compared to a more cumbersome activity of identifying the faults individually and sifting the combinations that lead to the failure of interest. The work presented in this paper is aimed at the development of a backward failure propagation methodology for analyzing the origins of functional failures in a conceptual design of systems including but not limited to nuclear, mechanical, aerospace, process, electrical/electronics, telecommunication, automotive, etc. This method allows the designer to achieve a robust early design based on the analyses of the system’s functional dependencies before proceeding to the detailed design and testing stages. The insights provided by the analysis at the conceptual design stage also reduce redesign efforts, testing costs, and project delays. The proposed method is a functional analysis approach that extends the Integrated System Failure Analysis for backward failure propagation. When provided with an abstract system configuration, a system’s functional model, and a system’s behavioral model, it utilizes a known functional state (typically a failure) to acquire system component modes and the states of other functions. The method includes inversion of the functional failure logic and component behavioral rules using propositional logic and deductive analysis to assess valid states of a system that satisfy the given initial conditions. To test the method’s scalability, we applied the proposed method to a simplified representation of the secondary loop of a typical pressurized water reactor.

Multidisciplinary structural optimization of novel high-aspect ratio composite aircraft wings

Novel high-aspect ratio airframe designs pave the way for a more sustainable aviation future. Such configurations enhance the aerodynamic efficiency of an aircraft through induced drag reduction mechanisms. Further performance gains, mainly in terms of structural mass, are accomplished via composite materials airframes. Nevertheless, undesired phenomena such as geometric nonlinearities and aeroelastic couplings due to elevated flexibility may often rise, rendering the design and optimization of such airframes extremely intricate and prohibitive in terms of computational cost. Low-fidelity tools, often preferred on the early design stages, accelerate the design process, albeit suffering from reduced accuracy and ability to capture higher-order phenomena. Contrastingly, high-fidelity computational methods incur excessive computational cost and are therefore utilized at the later, detailed design stages. There arises, therefore, the need for a combination of the various fidelities involved in a cost-effective manner, in order to drive the design towards optimal configurations without significant performance losses. In our approach, variable fidelity analyses are initially conducted in order to shed light on their effect on the structural response of a high-aspect ratio composite materials reference wing. An optimization framework combining low and high-fidelity tools in a sequential manner is then proposed, aiming at attaining a minimum mass configuration subject to multidisciplinary design constraints. As demonstrated, reasonable mass reduction was obtained for a future aircraft wing configuration.

Enabling rapid prediction of quantities to accelerate LCA for decision support in the early building design

Buildings are a significant contributor to climate change. This is why life-cycle assessments (LCA) are becoming increasingly popular for documenting environmental impacts during the detailed design stages of building projects, level of development (LOD) 300–400. In that context, wood is gaining recognition as a material that can reduce the embodied impacts of buildings. However, of particular concern is the incapability of research and practice to generate quantities rapidly in the early design stage. It is an underlying key issue for enabling LCA as decision support in these early building designs. Therefore, this study's aim is two-fold: (i) introducing a simplified design tool for wood dwellings and assessing how the predicted early design climate impacts perform compared to detailed design case studies (ii) evaluating the root causes for predicting trustworthy climate impacts in the early design. The LCAbyg tool assessed the impacts of the life-cycle phases A1-A5, B4, B6, and C3–C4. The climate impacts of the simplified designs (LOD 100–200) were analysed against ten detailed design buildings with the impact disaggregated into life-cycle phases, component types and material categories. The simplified design tool shows it is reliable for comparing the various GHG emissions associated with different designs. Still, the total impact is underestimated by an average of 12% compared with the detailed modelling. It primarily arises from the lack of simplified design metals and that a single product in a component can constitute up to 53% of the climate impact. So, the LCA is sensitive to chosen generic processes, EPDs, and quantities estimations. This study points to the critical elements in material quantification and related climate impact between simplified and detailed building designs. The study also adds to the body of scientific literature on wooden building designs by presenting the quantities and GWP results for ten dwellings constructed between 2010 and 2021. Terraced houses with specific design elements, paper wool, and footing foundation show promising carbon reduction abilities here. In addition, the simplified tool has the potential to get small and medium-sized enterprises in the building industry on board with the sustainability agenda and lead to broader adoption of LCA in their practices.

Approaches for assessing embodied environmental effects during the building design process

Buildings and construction are among the leading contributors towards global greenhouse gas emissions, resource demands, waste, and pollution, placing a massive strain on our natural environment. Until recently, mitigation strategies have primarily concentrated on reductions in operational energy, failing to account for embodied effects; those associated with the manufacture of construction goods, construction activities, and end of life considerations. In recent years, there has been an increased recognition of the growing significance of embodied effects, and the opportunity to reduce these during the building design process. However, life cycle assessment (LCA) tools used to quantify environmental flows are often perceived as being too time-consuming or complicated to incorporate into prevalent building design workflows. The aim of this study was to review approaches for assessing embodied environmental effects during the building design process, including the LCA tools and environmental data used to achieve this. A systematic review was conducted of academic and grey literature. The study identified three main approaches for incorporating LCA into the building design process: simplified LCA, detailed LCA and incremental LCA. Further analysis of these approaches was conducted, based on case studies. General attributes and design considerations were identified, and mapped against the early design, and detailed design stages. A wide variety of LCA approaches were reviewed, responding to various challenges for incorporating LCA into the building design process, with no singular approach able to completely satisfy all requirements. Findings highlight the lack of incremental LCA approaches, and the need for further research to understand how LCA approaches can be better used to improve the embodied environmental performance of buildings during the design process.

Structural Model Test for Strength Performance Evaluation of Disconnectable Mooring Apparatuses Installed on Floating-Type Offshore Wind Turbine

The destructive power of typhoons has been continuously increasing due to the influence of global warming. In a situation where the installation of floating wind turbines is increasing around the world, concerns about huge losses and collapses of floating offshore wind turbines due to strong typhoons are deepening. Regarding the safe operation of floating offshore wind turbines, the development of a new type of disconnectable mooring system is required. The newly developed disconnectable mooring apparatuses, such as fairlead chain stoppers (FCS) and submersible mooring pulleys (SMP), considered in this study are devised to more easily attach or detach the floating offshore wind turbine with mooring lines compared to other disconnectable mooring systems. In order to investigate the structural safety of the initial design of FCS and SMP that can be applied to MW class floating-type offshore wind turbines, scaled-down structural models were produced using a 3-D printer, and structural tests were performed on those models. For the structural tests of the scaled-down models, tensile specimens of the acrylonitrile butadiene styrene material used in the 3-D printing process were prepared, and the material properties were evaluated by performing tensile tests. Finite element analyses of FCS and SMP were performed by applying the material properties obtained from the tensile tests and the same load and boundary conditions as in the scaled-down model structural tests. Through the finite element analyses, the weak structural parts of FCS and SMP were reviewed. The structural model tests were performed considering the main load conditions of the fairlead chain stopper, and the test results were compared to the finite element analyses. Through the results of this study, it was possible to experimentally verify the structural safety of the initial design of disconnectable mooring apparatuses. Furthermore, the study results can be used to improve the structural strength of FCS and SMP in a detailed design stage.

Virtual reality-based assembly-level design for additive manufacturing decision framework involving human aspects of design

Abstract There is a combinatorial explosion of alternative variants of an assembly design owing to the design freedom provided by additive manufacturing (AM). In this regard, a novel virtual reality-based decision-support framework is presented herein for extracting the superior assembly design to be fabricated by AM route. It specifically addresses the intersection between human assembly and AM hence combining design for assembly, and design for additive manufacturing using axiomatic design theory. Several virtual reality experiments were carried out to achieve this with human subjects assembling parts. At first, a two-dimensional table is assembled, and the data are used to confirm the independence of non-functional requirements such as assembly time and assembly displacement error according to independence axiom. Then this approach is demonstrated on an industrial lifeboat hook with three assembly design variations. The data from these experiments are utilized to evaluate the possible combinations of the assembly in terms of probability density based on the information axiom. The technique effectively identifies the assembly design most likely to fulfill the non-functional requirements. To the authors’ best knowledge, this is the first study that numerically extracts the human aspect of design at an early design stage in the decision process and considers the selection of the superior assembly design in a detailed design stage. Finally, this process is automated using a graphical user interface, which embraces the practicality of the currently integrated framework and enables manufacturers to choose the best assembly design.