• Energy Research

The field of smart materials (SMs) is an area of great interest in the scientific community and one that is growing considerably from year to year due to the features this field brings to the development of high-performance products and applications. Considering these aspects, researchers choose to contribute to this field, and every year, an increasing number of scientific publications appear in the databases. Based on this consideration, the present paper approaches the domain of SMs from a quantitative perspective by carrying out a bibliometric analysis to provide young researchers with a mapping of the most important aspects, as well as the evolution of the field. The bibliometric analysis was carried out in the time frame 1990–2022 in the Web of Science (WoS) database, finding only selected research and review articles based on the most relevant keywords used in the domain. Based on the large number of results identified (8998 publications), the authors designed a classification of the most important aspects of bibliometric analysis.

Nowadays, companies are in the process of renewing their manufacturing lines by equipping them with modern five-axis CNC (computer numerical control) machining centers. The decision to select between different five-axis CNC machining centers, with similar technological capabilities is a difficult process, so the main goal of this work was to develop a method for assisting it. The proposed approach relies on seven technical criteria, four quantitative ones (traverse speed, thrust, spindle power, and spindle speed) which can be expressed by crisp numerical values, while the other three (flexibility, operation easiness, and setup time) are qualitative ones. The analytic hierarchy process (AHP) was used for ordering four variants of five-axis CNC milling machining centers. The qualitative criteria were processed using fuzzy systems to be expressed by crisp numerical values, suitable for AHP. Finally, the four variants of five-axis CNC milling machining centers were hierarchized and the best one was chosen. A sensitivity analysis was also unfolded to certify the robustness of the AHP.