Search results

As an advanced manufacturing method, additive manufacturing (AM) technology provides new possibilities for efficient production and design of parts. However, with the continuous expansion of the application of AM materials, subtractive processing has become one of the necessary steps to improve the accuracy and performance of parts. In this paper, the processing process of AM materials is discussed in depth, and the surface integrity problem caused by it is discussed.

Firstly, we listed and analyzed the characterization parameters of metal surface integrity and its influence on the performance of parts and then introduced the application of integrated processing of metal adding and subtracting materials and the influence of different processing forms on the surface integrity of parts. The surface of the trial-cut material is detected and analyzed, and the surface of the integrated processing of adding and subtracting materials is compared with that of the pure processing of reducing materials, so that the corresponding conclusions are obtained.

In this process, we also found some surface integrity problems, such as knife marks, residual stress and thermal effects. These problems may have a potential negative impact on the performance of the final parts. In processing, we can try to use other integrated processing technologies of adding and subtracting materials, try to combine various integrated processing technologies of adding and subtracting materials, or consider exploring more efficient AM technology to improve processing efficiency. We can also consider adopting production process optimization measures to reduce the processing cost of adding and subtracting materials.

With the gradual improvement of the requirements for the surface quality of parts in the production process and the in-depth implementation of sustainable manufacturing, the demand for integrated processing of metal addition and subtraction materials is likely to continue to grow in the future. By deeply understanding and studying the problems of material reduction and surface integrity of AM materials, we can better meet the challenges in the manufacturing process and improve the quality and performance of parts. This research is very important for promoting the development of manufacturing technology and achieving success in practical application.

A new backward punch shape was designed and used in the hydroforming process of double-layer Y-shaped tubes to achieve uniform wall thickness. This study focuses on the implementation and effectiveness of this novel punch shape.

A numerical simulation and experimental validation of the hydroforming process of double-layer Y-shaped tubes under various backward punch, replenishment ratios (left and right feed ratios) and internal pressure loading paths was performed using finite elements. During the hydroforming process, an analysis was made on the distribution of stress, strain and wall thickness in both the inner and outer layers of the Y-shaped conduit.

The novel backward punch parallel to the main tube has been found to improve the distribution of wall thickness in Y-shaped tubes. By controlling the feeding ratio and modifying the loading path of the internal pressure, it is possible to obtain the optimal forming part of the double-layer Y-shaped tube. The comparison between the simulation and experimental results of the double-layer Y-shaped tube formed under the optimal path indicates that the error is within 5% and the distribution of wall thickness is consistent.

A novel backward punch technique is employed to control the hydroforming process in a Y-shaped tube. A study on hydroforming of double-layer Y-shaped tubes with asymmetric features and challenging forming conditions is being suggested.

This paper aims to discuss the potentials of interdisciplinary exercises that bring together art and design methodologies in expanding as well as redefining the given methods and principles of basic design in architecture education. The primary purpose is to improve the conventional, well-established principles and methodologies of basic design studios into fresh perspectives.

Focussing on the case study of a basic design studio assignment that translated Richard Serra's Verb List (1967-68) into space-generating operations, the authors analyse how a diagonal interdisciplinary approach to studio pedagogy opened up the basic design studio into the exploration of new concepts and approaches. The assignment encouraged architecture students to productively and creatively engage with a significant art historical work for the purposes of design thinking and exploration.

Findings reveal that the students explored the possible reciprocal influences between materials, actions, and issues of form and organisation, thereby operating in an interface between art, architecture and design surveying the possible interactions between these disciplines. Based on the outcome of this studio exercise, the authors argue that designing assignments that would bring together various and sometimes even conflicting approaches of different fields allow us to reassess and conceptualise anew the pedagogical aims and modi operandi.

The research is original in the ways in which it suggests many possibilities of dialogue, interaction and collaboration between art, design and architecture studios.

Stab-resistant body armor (SRBA) is used to protect the body from sharp knives. However, most SRBA materials currently have the disadvantages of large weight and thickness. This paper aims to prepare lightweight and high-performance SRBA by 3D printing truss structure and resin-filling method.

The stab resistance truss structure was prepared by the fused deposition modeling method, and the composite structure was formed after filling with resin for dynamic and quasi-static stab tests. The optimized structural plate can meet the standard GA68-2019. Digital image correlation technology was used to analyze the local strain changes during puncture. The puncture failure mode was summarized by the final failure morphologies. The explicit dynamics module in ANSYS Workbench was used to analyze the design of the overlapped structure stab resistance process in this paper.

The stab resistance performance of the 3D-printed structural plate is affected by the internal filling pattern. The stab resistance performance of 3D-printed structural parts was significantly improved after resin filling. The 50%-diamond-PLA-epoxy, with a thickness of only 5 mm was able to meet the stab resistance standard. Resins are used to increase the strength and hardness of the material but also to increase crack propagation and reduce the toughness of the material. The overlapping semicircular structure was inspired by the exoskeleton structure of the demon iron beetle, which improved the stab resistance between gaps. The truss structure can effectively disperse stress for toughening. The filled resin was reinforced by absorbing impact energy.

The 3D-printed resin-filled truss structure can be used to prepare high-performance stab resistance structural plates, which balance the toughness and strength of the overall structure and ultimately reduce the thickness and weight of the SRBA.

A shared cognitive schema is the fundamental source of tacit understanding within a team. This study aims to address how such a shared cognitive schema emerges and evolves in an interdisciplinary research team.

This study uses an exploratory single case study to analyze the emergence and evolution of a shared cognitive schema in an interdisciplinary research team systematically. The authors spent more than two years collecting data from the IAM team via semistructured interviews, archival data and observation. Subsequently, a framework for the resulting mechanism model was developed by analyzing the data using a three-step process.

This study shows that as the interdisciplinary research team develops, the shared cognitive schema passes through three stages: overlapping cognitive schema, complementary cognitive schema and synergetic cognitive schema. The mechanisms of overlap, complement and synergy play important roles. The convergent roles of partner-based recruiting, knowledge categorization and following the existing institution facilitate the overlapping of knowledge structures. Complementary cognitive schema sharing is facilitated by interdisciplinary member selection, knowledge stock expansion and the effects of accomplished mentors. The synergetic behaviors of group voice, interactive cognition and adaptive learning facilitate synergetic cognitive schema sharing.

This study is the first to discuss the emergence and evolution of a shared cognitive schema at the microlevel of knowledge structure and belief structure. It offers a new theoretical perspective on the development rules of scientific research teams and provides practical enlightenment regarding the establishment and operation of interdisciplinary research teams.

Aluminum alloy is considered an ideal material in aerospace, automobile and other fields because of its lightweight, high specific strength and easy processing. However, low hardness and strength of the surface of aluminum alloys are the main factors that limit their applications. The purpose of this study is to obtain a composite coating with high hardness and lubricating properties by applying GO–PVA over MAO coating.

A pulsed bipolar power supply was used as power supply to prepare the micro-arc oxidation (MAO) coating on 6061 aluminum sample. Then a graphene oxide-polyvinyl alcohol (GO–PVA) composite coating was prepared on MAO coating for subsequent experiments. Samples were characterized by Fourier infrared spectroscopy, X-ray diffraction, Raman spectroscopy and thermogravimetric analysis. The friction test is carried out by the relative movement of the copper ball and the aluminum disk on the friction tester.

Results showed that the friction coefficient of MAO samples was reduced by 80% after treated with GO–PVA composite film.

This research has made a certain contribution to the surface hardness and tribological issues involved in the lightweight design of aluminum alloys.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0427/

The purpose of this paper is to describe various aspects of the visco-elastoplastic (VEP) behavior of porous-hardened concrete samples in relation to standard tests.

The problem is formulated on the basis of the rheological-dynamic analogy (RDA). In this study, changes in creep coefficient, Poisson's ratio, damage variables, modulus of elasticity, strength and angle of internal friction as a function of porosity are defined by P and S wave velocities. The RDA model provides a description of the degradation process of material properties from their peak state to their ultimate values using void volume fraction (VVF).

Compared to numerous versions of acoustic emission tracking developed to analyze the behavior of total wave propagation in inhomogeneous media with density variations, the proposed model is comprehensive in interpretation and consistent with physical understanding. The comparison of the damage variables with the theoretical variables under the assumption of spherical voids in the spherical representative volume element (RVE) shows a satisfactory agreement of the results for all analyzed samples if the maximum porosities are used for comparison.

The paper presents a new mathematical-physical method for examining the effect of porosity on the characteristics of hardened concrete. Porosity is essentially related to density variations. Therefore, it was logical to define the limit values of porosity using the strain energy density.

This study aims to develop a four-dimensional (4D) textile composite that self-forms upon thermal stimulation while eliminating thermomechanical programming steps by using fused deposition modeling (FDM) 3D printing technology, and tries to refine the product development path for this composite.

Polylactic acid (PLA) printing filaments were deposited on prestretched Lycra-knitted fabric using desktop-level FDM 3D printing technology to construct a three-layer structure of thermally responsive 4D textiles. Subsequently, the effects of different PLA thicknesses and Lycra knit fabric relative elongation on the permanent shape of thermally responsive 4D textiles were studied. Finally, a simulation program was written, and a case in this study demonstrates the usage of thermally responsive 4D textiles and the simulation program to design a wrist support product.

The constructed three-layer structure of PLA and Lycra knitted fabric can self-form under thermal stimulation. The material can also achieve reversible transformation between a permanent shape and multiple temporary shapes. Thinner PLA deposition and higher relative elongation of the Lycra-knitted fabric result in the greater curvature of the permanent shape of the thermally responsive 4D textile. The simulation program accurately predicted the permanent form of multiple basic shapes.

The proposed method enables 4D textiles to directly self-form upon thermal, which helps to improve the manufacturing efficiency of 4D textiles. The thermal responsiveness of the composite also contributes to building an intelligent human–material–environment interaction system.

According to the Ministry of Tourism and Creative Economy, there are 7,275 indigenous tourism enterprises in Indonesia. However, only 0.5% of these are certified as a sustainable tourism village. One of them is the Karangrejo village in Borobudur, Indonesia. This village is able to sustain their enterprise, which is a unique and rare context. This study aims to address this gap by examining the sense of place value created from the collaboration between actors, mapping the actors and their resources who have crucial roles in indigenous tourism enterprise, and examining the relations between actors, mapping the characteristics and efforts made by the indigenous tourism enterprise. The novelty of this research is the unique context that it takes place, and the use of comprehensive theoretical perspectives combining architecture, sociological social psychology and marketing/business theories in tourism context, which is uncommon for research in this area.

Participants in this study were 17 individuals, comprising Village Chief, accompanying state-owned enterprises, tourists, owners of micro, small and medium enterprises, village economic center manager and village-owned enterprises manager. Data were collected from interviews and field recordings using purposive sampling technique. The study design was a case study. The data were coded in two steps: first cycle and second cycle coding. Member checking with research participants was conducted to ensure data credibility.

This study revealed several novel findings. First, sense of place value was not merely perceived as material and nonmaterial components, but also as networks between actors that were involved in creating such components within (value) exchange framework. Second, the actors involved in the exchange were provider actor, external supporter actor, internal supporter actor, collaborator actor and consumer actor. Each of these actors owned one or a combination of material and nonmaterial values that are exchangeable. Mapping of the actors involved was discussed using a combined perspective of consumer-centric and balanced network. Third, exchange relations that occurred between actors could be balanced or imbalanced, depending on the amount of resource owned by each actor. Nonetheless, imbalanced relations because of discrepancies in the value contributions could still have positive impact because it was motivated by the intention to help others. Fourth, this study identified the importance of having characteristics as resource integrator/gatherer for indigenous tourism enterprise (provider actor) to ensure the economic sustainability of their business.

This study was conducted during the COVID-19 pandemic, where governments imposed strict travel restrictions. Consequently, data from tourists were limited in particular, the lack of perspectives from international tourists. During the data collection, the government were still limiting international travelers to visit the country, hence only domestic tourists were able to visit. The perspectives of international tourists would have added valuable data. Because of pandemic, the data collection process was initially conducted online, which was then followed by in-person data collection. Online data collection is common in research; however, in-person data collection would have been more preferred, where possible, so that the researchers could directly observe the situation in context. Future research could be conducted after the pandemic ends. Furthermore, findings of this research asserted the importance of actors’ motives, situations, quality of the values and relational attributes, but had not discussed these in detail, especially from the perspective of each actor. Future research could address this limitation.

Enhancing material and nonmaterial sense of place value would involve multiple actors. Therefore, mapping of the resources owned by these actors as well as their roles is critical. To create sense of place value, synergy between actors is essential and could not be achieved by a single actor. Every actor is influenced by motives and circumstances when interacting with the other actor. Awareness of such motives and circumstances where the exchange takes place is necessary, to ensure that the cultivated relationship aligns with the goals and expectations. As exchange relations could be balanced or imbalanced, every actor also needs to be aware of their position and continuously evaluate it to avoid being constantly in a powerless position. Indigenous tourism enterprise could not singlehandedly provide every resource needed. Therefore, developing a character as a gatherer/resource integrator becomes crucial to gain access to all necessary resources. Currently, there are no tools available for identifying actors, resources and relational attributes. This could be a potential avenue for academics in this area. Further, the government should identify the best practice from the successful indigenous tourism enterprises, not only giving recognition awards or certifications to these enterprises.

Findings from this study have several contributions; among others, it discussed sense of place value of indigenous tourism enterprise more comprehensively, as the essential actors who exchange resources were identified. This study also underlined positive power imbalance, which had been generally seen as a negative dynamic. Moreover, this study highlighted that indigenous people, despite living by communal value (non-transactional) in their daily lives, would need to engage in transactional relations and develop resource integrator characteristics to maintain tourism enterprise. Indigenous people have often been seen from their communal side, while their transactional (non-communal) side has been rarely seen.

This paper proposes a new metric, named Operational Space Efficiency (OpSE), intended to diagnose and quantify the inefficient use of floor space for stocking materials in industrial workstations. OpSE presents a formulation analogous to the well-known Overall Equipment Effectiveness and can be obtained as the product of three distinct indicators: Standard Compliance Effectiveness, Standards Selection Effectiveness and Design Space-usage Effectiveness.

This indicator scrutinizes how usefully floor space in workstations is used to temporarily stock materials in the form of raw materials, semi-finished products, parts and components. It is suited for analyzing fixed-position layouts as well as product layouts typical of repetitive manufacturing settings, such as assembly lines in the automotive sector. The proposed indicator leverages an appropriate loss structure that features those factors affecting floor space utilization in workstations with regard to supplying and stocking materials.

An Italian manufacturer in the field of electro-technology was used as an industrial case study for the application of the methodology. The application shows how the three indicators work in practice, the effectiveness of OpSE and the methodology as a whole, in diagnosing floor space usage inefficiencies and in properly addressing improvement actions of the internal logistics in industrial settings.

The paper scrutinizes some important Key Performance Indicators (KPIs) dealing with space usage efficiency and identifies some significant drawbacks. Then it suggests a new, inclusive structure of losses and a KPI that not only measures efficiency but also allows to identify viable countermeasures.