Engineering reports : open access最新文献

Additive Manufacturing (AM) has revolutionized the production industry by offering design freedom with shorter lead times and reduced material wastage. However, the damage tolerance (DT) of AM parts is a significant concern due to their microstructural and geometric complexities, which affect their mechanical performance. This article aims to provide a comprehensive overview of the manufacturing parameters affecting the components produced by AM specifically selective laser melting (SLM). Detailed discussions are presented on the effects of manufacturing attributes on the microstructure, defects, and mechanical characteristics of AM parts. Depending on these aspects, basic concepts are studied and critically explained specifically for AM materials. The basic criterion for damage-tolerant component design, the criterion for fatigue and fracture properties, and the effect of the defects on fatigue life are critically presented. In addition, the effect of different types of gradation on the crack growth behavior of samples processed by SLM is also investigated in depth. There is currently a lack of a specific review study in the literature that establishes a connection between process attributes and metallographic properties, and their impact on the damage behavior of additively manufactured parts. This gap in research highlights the need for a comprehensive review to bridge this knowledge deficit and provide valuable insights for understanding the relationships between manufacturing processes, material characteristics, and the structural integrity of additively manufactured components. This review concludes by addressing the challenges and opportunities in designing and qualifying AM parts for damage tolerance.

S. K. VR, A. Mariappan, U. K. Thianesh, et al., “The Proof of Concept of Uninterrupted Push-Pull Electromagnetic Propulsion and Energy Conversion Systems for Drones and Planet Landers,” Engineering Report 6, no. 1 (2024): e12703, https://doi.org/10.1002/eng2.12703.

The affiliations for the corresponding author were mispresented. The correct affiliation is below:

Amity University Uttar Pradesh, Amity Institute of Aerospace Engineering, Noida, India

We apologize for this error.

Residential cooking with non-renewable energy sources, such as firewood, charcoal, natural gas, participate in the emission of more than a gigaton of CO₂ per year, which represents 2% of the global CO₂ emissions. Additionally, toxic particles including sulfur dioxide, carbon monoxide, and mercury are released leading to elevated levels of indoor air pollution, and adversely affecting the health of the inhabitants. The residential sector's non-renewable energy cooking devices also pose significant problems, consuming approximately 30%–40% of global energy usage, with over 80% dedicated to cooking applications. To mitigate the negative impacts of traditional cooking on health and the environment, various renewable energy-based cooking technologies have been developed recently. The primary contributions of our paper are to: (a) present a comprehensive review of concentrated solar thermal cooking technologies, assessing their social, economic, and environmental impact across different climatic zones in developing countries like India; (b) classify and compare different solar cooking technologies, highlighting their advantages and limitations in various scenarios; (c) evaluate the energy efficiency of diverse solar cooking technologies; (d) analyze the impact of solar cookers on communities in developing countries; and (e) identify the challenges and future directions for solar cooker technologies, particularly in solar community kitchens. Our novel findings demonstrate that using solar cooking devices can reduce energy consumption by up to 56% in Indian schools. Moreover, the payback period ranges from 3 to 6 years, contingent on the technology's cost, climatic conditions, and available subsidies. Consequently, significant positive impacts on society, the economy, and the environment are observed when traditional cooking devices are replaced by solar cooking devices. This study provides a unique and thorough analysis, contributing to the growing body of knowledge on sustainable cooking solutions and their potential to transform energy consumption patterns in developing regions.

The field of flexible electronics has experienced remarkable expansion in response to the escalating demand for lightweight, bendable, and multifunctional electronic devices. As the world increasingly integrates electronics seamlessly into everyday life, the importance of flexible electronics becomes more apparent. While existing reviews have examined materials used in flexible devices, they often overly focus on specific materials or provide broad generalizations about different material types. Thus, this review offers a concise yet comprehensive overview of critical inorganic film materials crucial to the advancement of flexible and wearable devices. Each material is introduced with a succinct overview of its structure and production processes. This review elucidates their unique characteristics and potential applications in flexible electronics by comparing their mechanical, electrical, and thermal properties. This review is a valuable resource for researchers entering this emerging field of flexible electronics, providing a concise yet comprehensive insight and property comparisons. Accompanied by figures illustrating material structures and applications, readers will gain access to summarized discussions. Comparative figures of material properties will enhance comprehension. Additionally, discussions on diverse applications will offer insight into their versatility across various fields of flexible electronics.

The transformation of power system networks is slowly taking shape, the advent of interruptive technological platforms dealing with digitalization and real-time trading of power has gained attention based on incorporation of more renewables into the grid. The stochastic nature of renewables pauses security of supply challenges and other related stability concerns, and for this reason efficient methods are investigated in this review to build an understanding of microgrid energy management system (MG-EMS) and distribution-based energy management strategies aimed at transforming the conventional grid network into smart grid network. In essence, propagating a technological shift to microgrids which have proven to be ideal distribution networks for residential and commercial loads, have become indispensable in handling distributed energy resources (DER), such as solar, PV, wind, battery energy storage systems (BESS) and small-scale microgrids, for example in case of excess supply, energy storage system (ESS) has been formulated as a solution to curb excess supply and can offer ancillary services to the grid network. Within the perspective of electricity generation and distribution, microgrid control methodologies, distribution network (DN) management approaches and incumbent optimization strategies used to coordinate and manage grid-level uncertainties are investigated. In addition, this study proposes distributionally robust optimization (DRO), to manage and mitigate risks associated to shortage or oversupply of power from RESs.

Friction Stir Processing (FSP) has become a famous solid-state technology for the fabrication of a wide range of aluminum alloy-based composites that today find multiple applications across the various metal industries. Generation of revolving, ribbon, bulk, excessive or mass flash as it is generally termed has been a common problem in numerous FSP works. When confronted by this challenge, many researchers apply different experimental and numerical modeling approaches or strategies to reduce the mass flash to practically acceptable limits since it often leads to undesirable loss of material and is also an unwanted defect. This subject is deficiently reviewed, and it therefore becomes the thrust of this paper, to investigate the common trends in mass flash generation during FSP and its commonly employed reduction strategies. Mass flash is caused by high rotational speed at low travel speed and vice versa, flat shoulder, no and low tilt angles, high plunge depth, axial force, and travel force. Mass flash causes material loss, loss of volume fraction control target, material thinning, and leads to poor quality fabrications. Mass flash reduction strategies include the use of high tool tilt angles, concaved tool shoulder, proportional rotational speed and travel speed, and optimal plunge depth, axial force and travel speed as supported by both the experimental and numerical modeling studies.

Aluminum alloy AlSi10Mg is a widely used engineering material that offers a very high strength-to-weight ratio and easy processing. It is common in the aerospace, medical, and automotive industries and has excellent machining and casting properties, as well as being easily made into fine powder. In recent years, it has become one of the most common light-weight materials for additive manufacturing (AM). Its chemical composition and stability in powder form make it particularly ideal for laser powder bed fusion (LPBF) applications. It is one of the few available aluminum alloys that can be reliably processed using AM. Numerous studies have been dedicated to mechanical properties and design strategies, but much less attention has been given to corrosion behavior. This article reviews the corrosion behavior and the correlation between the microstructure and corrosion for AlSi10Mg when fabricated using an LPBF process. Specific topics reviewed include corrosion performance, corrosion issues (pores, surface roughness, and residual stresses), and passive film formation mechanisms and compare these to conventionally-manufactured counterparts. In addition, this review discusses available methods for mitigating and avoiding corrosion in LPBF-processed AlSi10Mg parts, including relevant post-processing methods.

This paper presents a method aimed at improving comprehension of AC electric machine principles by facilitating the learning of the Rotating Magnetic Field (RMF) through visualization tools provided by Finite Element Method (FEM) software. First, traditional methods used in textbooks to explain RMF in electric machines are reviewed, with an analysis of various instructional strategies. Acknowledging the limitations of these conventional approaches and the inherent complexity of RMF comprehension, a novel visualization method is proposed. Understanding RMFs in electric machines is fundamental for electrical engineers due to their crucial role in electric machine design and optimization. While textbooks typically rely on mathematical explanations and simple sketches, advancements in computer and software technology offer opportunities to utilize finite element tools for enhanced comprehension. Through dynamic animations and interactive simulations, emphasis is placed on prioritizing conceptual understanding over mathematical descriptions. Furthermore, this paper explores the development of pre-simulation models in FEM tools to facilitate RMF learning in AC electric machines, and the process of creating a model to teach rotating magnetic fields in electric machines is carefully outlined. This approach holds promise for engineers seeking a deeper understanding of electric machines and can also be utilized by educators to enhance their teaching methodologies.

Noise: an enemy to be dealt with and a major factor limiting communication system performance. However, what if there is gold in that garbage? In conventional engineering, our focus is primarily on eliminating, suppressing, combating, or even ignoring noise and its detrimental impacts. Conversely, could we exploit it similarly to biology, which utilizes noise-alike carrier signals to convey information? In this context, the utilization of noise, or noise-alike signals in general, has been put forward as a means to realize unconditionally secure communication systems in the future. In this tutorial article, we begin by tracing the origins of thermal noise-based communication and highlighting one of its significant applications for ensuring unconditionally secure networks: the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange scheme. We then delve into the inherent challenges tied to secure communication and discuss the imperative need for physics-based key distribution schemes in pursuit of unconditional security. Concurrently, we provide a concise overview of quantum key distribution schemes and draw comparisons with their KLJN-based counterparts. Finally, extending beyond wired communication loops, we explore the transmission of noise signals over-the-air and evaluate their potential for stealth and secure wireless communication systems.

Wireless power transfer (WPT) is a promising technology that has the potential to revolutionize the present methods of power transmission. This paper aims to provide an overview of WPT, including its history, a comparative review of methods, and a review of recent papers about WPT. We discussed different methods of WPT, such as inductive power transmission, capacitive power transmission, optical power transmission, and microwave power transmission. The research briefly discusses the applications, challenges, and opportunities of WPT. The study's findings suggest that WPT can serve as a feasible substitute for traditional wired power transmission. This technology has the potential to offer several advantages, including enhanced convenience, decreased expenses, and heightened safety.