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The actual concern for structural engineers is the failure of the structural material to meet the design safety and the safe service life of large span and wide floor space buildings. The main idea in this present report reflects the combination of the economical use of construction materials with the long and durable safe service life to cover large floor spaces, using precast and prestreseed concrete shell structural members. This paper describes the present ongoing numerical and experimental analysis model used to determine the structural long duration flexural and nonlinear deformation characteristics of reinforced precast elliptical paraboloid concrete shell elements, prestressed in both directions. Horizontal precast and prestressed edge beams supported on prestressed columns are provided to support the longitudinal edges of the shells. This present study has been based on nonlinear differential equations of the concrete matrix creep theory which reflects the correlation between the matrix stress and strain by its modulus of elasticity and on the well-known geometrical preconditions of the theory of elasticity concerning thin plates with small flexural deformations. For structural and crack predictions, the well-known virtual work principles have been used to estimate (a) transient bi-directional strains due to the matrix creep and shrinkage, (b) the resulting time-dependent bi-directional stress redistribution, as well as (c) bi-directional displacement variations in the structural shell elements and finally (d) bi-directional pre-stressing losses in the pre-stressed high yield tendons. The concrete shear stresses have been evaluated by the well-known principle of Juravskiy. A series of original test experiments with once evaluated strength parameters has been planned to be successfully used to provide encouraging support for the numerical evaluations.

Dual design for additive manufacturing (DfAM) takes into account both the opportunities and constraints of AM simultaneously, which research shows is more effective than considering them separately. Unlike existing reviews, this paper aims to map DfAM research within the engineering design process, focusing solely on studies adopting dual DfAM. Additionally, it aims to suggest future research directions by analysing prominent research themes and their inter-relationships. Special emphasis is on theme inter-relationships concerning the conceptual, embodiment and detail design phases.

The study is based on a systematic literature review of 148 publications from January 2000 to February 2024. After screening, prominent research themes were identified and systematically analysed. Theme inter-relationships were explored using quantitative analysis and chord diagrams.

The findings reveal that studies either span the entire design process, the early design phases or the later design phases. Most research focuses on the later design phases, particularly within themes of design optimisation, design evaluation and AM-specific manufacturing constraints. The most frequent theme inter-relationship occurs between design optimisation and AM-specific manufacturing constraints. Overall, the findings suggest future research directions to advance dual DfAM research, such as development of design rules and guidelines for cellular structures.

This review proposes a model by mapping prominent themes of dual DfAM research in relation to the engineering design process. Another original contribution lies in analysing theme inter-relationships and visualising them using chord diagrams – a novel approach that did not exist before.

This paper aims to propose a new framework on prioritizing and deployment of design for additive manufacturing (DfAM) strategies to an industrial component using Fuzzy TOPSIS multiple criteria decision-making (MCDM) techniques. The proposed framework is then applied to an automotive component, and the results are discussed and compared with existing design.

Eight DfAM design alternatives associated with eight design criteria have been identified for framing new DfAM strategies. The prioritization order of the design alternatives is identified by Fuzzy TOPSIS MCDM technique through its closeness coefficient. Based on Fuzzy TOPSIS MCDM output, each of the design alternatives is applied sequentially to an automobile component as a case study. Redesign is carried out at each stage of DfAM implementation without affecting the functionality.

On successful implementation of proposed framework to an automotive component, the mass is reduced by 43.84%, from 0.429 kg to 0.241 kg. The redesign is validated by finite element analysis, where von Mises stress is less than the yield stress of the material.

The proposed DfAM framework and strategies will be useful to designers, R&D engineers, industrial practitioners, experts and consultants for implementing DfAM strategies on any industrial component without impacting its functionality.

To the best of the authors’ knowledge, the idea of prioritization and implementation of DfAM strategies to an automotive component is the original contribution.

The purpose of this paper is to present a case study of a country with severe problems in the telecommunications sector, including corruption and maladministration.

The paper presents a review of the legislation and regulatory decisions over the last decade, plus prosecutions in the USA for bribery in the country.

The paper reveals that, despite a decade of external efforts to encourage the use of information communication technology to boost development, very little progress has been made in terms of policy, legislation and regulation. No lessons appear to have been learned; the same mistakes could be repeated.

Further case studies are required from West Africa to provide a more complete picture and to assess whether equally serious problems exist in the region.

There is a need for a review of the legislation both for telecommunications and for corruption, with considerable strengthening of institutions and proper democratic accountability.

Citizens in this country have seen much greater access to mobile telephony, but in a haphazard way. There has been no regard for their interests (e.g. higher charges), nor consideration of how bribery, high licence fees and avoidance of customs duties affect them.

This is one of the few case studies of telecommunications in West Africa. It addresses issues of corruption, an issue seldom discussed.

This paper aims to provide a review of four-dimensional (4D) printing using fused-deposition modeling (FDM). 4D printing is an emerging innovation in (three-dimensional) 3D printing that encompasses active materials in the printing process to create not only a 3D object but also a 3D object that can perform an active function. FDM is the most accessible form of 3D printing. By providing a review of 4D printing with FDM, this paper has the potential in educating the many FDM 3D printers in an additional capability with 4D printing.

This is a review paper. The approach was to search for and review peer-reviewed papers and works concerning 4D printing using FDM. With this discussion of the shape memory effect, shape memory polymers and FDM were also made.

4D printing has become a burgeoning area in addivitive manufacturing research with many papers being produced within the past 3-5 years. This is especially true for 4D printing using FDM. The key findings from this review show the materials and material composites used for 4D printing with FDM and the limitations with 4D printing with FDM.

Limitations to this paper are with the availability of papers for review. 4D printing is an emerging area of additive manufacturing research. While FDM is a predominant method of 3D printing, it is not a predominant method for 4D printing. This is because of the limitations of FDM, which can only print with thermoplastics. With the popularity of FDM and the emergence of 4D printing, however, this review paper will provide key resources for reference for users that may be interested in 4D printing and have access to a FDM printer.

Practically, FDM is the most popular method for 3D printing. Review of 4D printing using FDM will provide a necessary resource for FDM 3D printing users and researchers with a potential avenue for design, printing, training and actuation of active parts and mechanisms.

Continuing with the popularity of FDM among 3D printing methods, a review paper like this can provide an initial and simple step into 4D printing for researchers. From continued research, the potential to engage general audiences becomes more likely, especially a general audience that has FDM printers. An increase in 4D printing could potentially lead to more designs and applications of 4D printed devices in impactful fields, such as biomedical, aerospace and sustainable engineering. Overall, the change and inclusion of technology from 4D printing could have a potential social impact that encourages the design and manufacture of such devices and the treatment of said devices to the public.

There are other 4D printing review papers available, but this paper is the only one that focuses specifically on FDM. Other review papers provide brief commentary on the different processes of 4D printing including FDM. With the specialization of 4D printing using FDM, a more in-depth commentary results in this paper. This will provide many FDM 3D printing users with additional knowledge that can spur more creative research in 4D printing. Further, this paper can provide the impetus for the practical use of 4D printing in more general and educational settings.

Additive manufacturing (AM) allows companies to create additional value in the processes of new product development and order fulfillment. One of the challenges for engineers is to identify suitable parts and applications for additive manufacturing. The purpose of this paper is to investigate the relation between value creation and the design process. The implications of this relation provide an orientation on the methods for identifying parts and applications for additive manufacturing.

Mapping the value clusters of AM on design strategies allows determining the expected degree of change in design. A classification into major and minor design changes is introduced to describe the predictability of the impact of AM on past performance and business model. The ability to predict the future properties of an AM part determines the suitability of identification and selection methods from literature. The mapping is validated by an identification process that creates a shortlist of potential AM parts based on the strategic decision for a value cluster. Shortlisted parts are then evaluated based on the criteria technology readiness, required post-processing, customer benefit and manufacturer benefit.

The mapping of value clusters on expected design changes determines the type of selection process. For minor design changes, automated part identification serves as a powerful tool while major design changes require the judgment of skilled engineers.

The mapping of value clusters to design strategies and degree of change in design is based on empirical observations and conclusions. The mapping has been validated in an industrial context in different identification and selection processes. Nevertheless the versatility of AM and industrial environments impede a universal validity of high-level concepts.

This value-driven process of identification and selection was applied in technology transfer projects and proved to be useful for AM novices and experts. The mapping supports the identification and selection process, as well as the general product development process by providing an indication of the design effort for implementing AM.

The novel mapping links the economic domain of value creation to the engineering domain of design strategies to provide guidance in the selection of economically and technically suitable parts for additive manufacturing.

Additive manufacturing has rapidly developed in terms of technology and its application in various types of industries. With this rapid development, there has been significant research in the area of materials. This has led to the invention of Smart Materials (SMs). The 4D printing is basically 3D printing of these SMs. This paper aims to focus on novel materials and their useful application in various industries using the technology of 4D printing.

Research studies in 4D printing have increased since the time when this idea was first introduced in the year 2013. The present research study will deeply focus on the introduction to 4D printing, types of SMs and its application based on the various types of stimulus. The application of each type of SM has been explained along with its functioning with respect to the stimulus.

SMs have multiple functional applications pertaining to appropriate industries. The 4D printed parts have a distinctive capability to change its shape and self-assembly to carry out a specific function according to the requirement. Afterward, the fabricated part can recover to its 3D printed “memorized” shape once it is triggered by the stimulus.

The present study highlights the various capabilities of SMs, which is used as a raw material in 4D printing.

Acrylonitrile butadiene styrene is an important material in 3D printing due to its strength, durability, heat resistance and cost-effectiveness. These properties make it suitable for various applications, from functional prototypes to end-use products. This study aims to model and predict the mechanical properties of acrylonitrile butadiene styrene parts produced using the fused deposition modeling process.

The experiment was carefully designed to determine the optimal print parameters, including layer thickness, nozzle temperature and infill density. Tensile tests were performed on all printed samples following industry standards to gauge the mechanical properties such as elastic modulus, ultimate tensile strength, yield strength and breakpoint. Taguchi optimization and variable analysis were used to explore the relationship between mechanical properties and print parameters. Furthermore, an artificial neural network (ANN) regression model was implemented to predict mechanical properties based on varying print conditions.

The results demonstrated that layer thickness has the most significant influence on mechanical properties when compared to other print conditions. The optimization approaches indicated a clear relationship between the selected print parameters and the material’s mechanical response. For acrylonitrile butadiene styrene material, the optimal print settings were determined to be a 0.25 mm layer thickness, a 270 °C nozzle temperature and a 30 % infill density. Moreover, the ANN model notably excelled in predicting the yield strength of the material with greater accuracy than other mechanical properties.

Comparing the accuracy and capabilities of the Taguchi and ANN models in analyzing mechanical properties, it was found that both models closely matched the experimental data. However, the ANN model showed superior accuracy in predicting tensile outcomes. In conclusion, while the ANN model offers higher predictive accuracy for tensile results, both Taguchi and ANN methods are effective in modeling the mechanical properties of 3D-printed acrylonitrile butadiene styrene materials.

There are many investigations in design methodologies, but there are also divergences and convergences as there are so many points of view. This study aims to evaluate to corroborate and deepen other researchers’ findings, dissipate divergences and provide directing to future work on the subject from a methodological and convergent perspective.

This study analyzes the previous reviews (about 15 reviews) and based on the consensus and the classifications provided by these authors, a significant sample of research is analyzed in the design for additive manufacturing (DFAM) theme (approximately 80 articles until June of 2017 and approximately 280–300 articles until February of 2019) through descriptive statistics, to corroborate and deepen the findings of other researchers.

Throughout this work, this paper found statistics indicating that the main areas studied are: multiple objective optimizations, execution of the design, general DFAM and DFAM for functional performance. Among the main conclusions: there is a lack of innovation in the products developed with the methodologies, there is a lack of exhaustivity in the methodologies, there are few efforts to include environmental aspects in the methodologies, many of the methods include economic and cost evaluation, but are not very explicit and broad (sustainability evaluation), it is necessary to consider a greater variety of functions, among other conclusions

The novelty in this study is the methodology. It is very objective, comprehensive and quantitative. The starting point is not the case studies nor the qualitative criteria, but the figures and quantities of methodologies. The main contribution of this review article is to guide future work on the subject from a methodological and convergent perspective and this article provides a broad database with articles containing information on many issues to make decisions: design methodology; optimization; processes, selection of parts and materials; cost and product management; mechanical, electrical and thermal properties; health and environmental impact, etc.

The purpose of this study is the use of 3D printing technology to perform maintenance on damaged parts on site. To maintain damaged parts, the user needs experience in the parts design and 3D printing technology. To help users who have little or no experience on 3D printing, a part library-based information retrieval and inspection framework was proposed to support the process of manufacturing replaceable parts using a 3D printer.

To establish the framework, 3D printing-based maintenance procedure was first defined, comprising retrieval, manufacturing and inspection steps, while identifying the technical components required to perform the procedure. Once the technical components are identified, part library-based information retrieval and inspection framework was defined based on the technical components and the relationships between the components. For validation of the concept of the framework, prototype system is developed according to the proposed framework.

The feasibility of the proposed framework is proved through maintenance experiments on gaskets and O-rings.

The main contribution of this study is the proposal of the framework, which aims to support the maintenance of damaged parts for the user who has little or no experience in part design or does not know how to operate a 3D printer.