The reduction of consumption and pollutant emissions is a top priority for the transport sector. One working line is the substitution of conventional structural materials with lightweight materials such as metallic alloys of aluminium, titanium, and/or magnesium. For this reason, and considering that the number of related articles is lower than the existing number of other structural lightweight materials, it is considered very convenient and helpful to carry out a systematic analysis of their latest trends through Open Access literature. A methodology adapted from the PRISMA statement is applied, in order to guarantee unbiasedness and quality in selecting literature and research. The final selection is made up of the 40 most cited research papers from 2015–2020, with an average of 20.6 citations per article. Turning and drilling are the most trending machining processes, and there is particular interest in the study of sustainable cooling, such as dry machining, cryogenic cooling, and MQL. In addition, another trending topic is multi-materials and joining dissimilar materials with guarantees. Additive manufacturing has also been identified as an increasingly trending theme, appearing in 18% of the selected studies. This work is complemented with summary tables of the most cited Open Access articles on sustainable machining and cooling, multi-materials or hybrid components, and additive manufacturing.
The aeronautical and automotive industries have, as an essential objective, the energy efficiency optimization of aircraft and cars, while maintaining stringent functional requirements. One working line focuses on the use of lightweight structural materials to replace conventional materials. For this reason, it is considered enlightening to carry out an analysis of the literature published over the last 20 years through Open Access literature. For this purpose, a systematic methodology is applied to minimize the possible risks of bias in literature selection and analysis. Web of Science is used as a search engine. The final selection comprises the 30 articles with the highest average numbers of citations per year published from 2015 to 2020 and the 7 articles published from the period of 2000–2014. Overall, the selection is composed of 37 Open Access articles with 2482 total citations and an average of 67.1 citations per article/year published, and includes Q1 (62%) and Q2 (8%) articles and proceeding papers (30%). The study seeks to inform about the current trends in materials and processes in lightweight structural materials for aeronautical and automotive applications with a sustainable perspective. All the information collected is summarized in tables to facilitate searches and interpretation by interested researchers.
In occupational exposure to vibration, the risk assessment process is defined through a regulatory framework that presents some relevant metrological problems. This framework considers methods based on estimation and on measurements. Estimation methods could employ existing information that is provided for each manufacturer to each individual tool or application to carry out such estimation. The use of estimation methods has some problems, such as substantial uncertainty. When using measurement methods, some metrological aspects are not fully defined. Therefore, a new and emerging risk appears due to certain methodologic limitations. Consequently, the variation between the estimated and the actual values could overestimate the level of occupational exposure to vibrations. Thus, with this paper, a critical analysis of this emerging metrological problem is provided. For this, a critical analysis of the metrological requirements regarding European standards is developed. To this end, the estimation method and measure method are investigated, considering, in both cases, the main factors related to uncertainty, reliability, and traceability. With this structure, a set of metrological limitations have been identified, thus pointing towards future lines of research that allow the improvement of the process of assessing the level of occupational exposure to vibrations.
This paper presents the new transfer standard for torque measurements in the MN7m range and its metrological characterization through FEM analyses. Current methods used for torque measurements in such measuring range are not traceable to international standards; this situation has a deep impact in several industries, being especially important in wind energy generation. In order to improve the quality of torque measurements during wind turbine tests, the “EMPIR 14IND14 -Torque measurements in the MN7m range”, a new European funded project, has been launched. This project aims to develop new transfer standards for obtaining accurate, reliable, traceable torque measurements in the facilities used for testing wind turbine’s performance. Within this project, CEM (Spanish Center of Metrology) has designed a new transfer standard for torque measurements, named “Force lever system”. Modeling and simulation technologies have been used, not only for designing and testing the proposed system, but also for enabling the estimation of its future associated uncertainty even before it being manufactured. The results have proven that the expected metrological behavior of the designed system will ameliorate the accuracy of current measuring methods, while ensuring torque measurements traceability. The improvement of the torque measurements reliability will make it possible to better diagnose its behavior and to improve wind energy generation efficiency.
This paper analyzes the efficiency and sustainability of facing operations that are required within maintenance operations in the aeronautical industry. Due to the elevated cost and environmental impact of such processes, reducing the operating time while repairing parts is required. In this work, an experimental study of intermittent facing carried out on a magnesium alloy rod was developed. The experiment resembles real repair and maintenance machining operations, where an intermittent facing represents a more realistic scenario and where the results obtained in continuous turning studies are not always applicable. The work was performed with different cooling and lubrication systems and various cutting conditions, also considering the size of the interruption to analyze their impact in the surface roughness. To this end, surface finished in different measuring zones was studied. The aims of the study are to get a better understanding of the intermittent facing process in magnesium alloys typically employed in aeronautical applications and find the most efficient cutting parameters to obtain an improved surface under the safest and most environmentally respectful conditions.