Smart structures, materials and nano technology in engineering

Smart materials are active materials that are nowadays commonly used for sensing, actuation, and transduction for structural noise (acoustic), shape (morphing) and vibration control and health monitoring of (in historical order) offshore petroleum, aerospace, aeronautic, mechanical, civil (including infra-structures and wind turbines) and biomedical engineering. More recently, they were also used for energy harvesting from environment for autonomously and wirelessly powering of various temperature or pressure monitoring sensors and some medical (fluidic) implants and (surgery) devices. When surface bonded on- or embedded into-passive structures, smart materials provide them with additional active functionalities such as autonomously, wirelessly and self-reacting to their deformation or stress states and surrounding environment; thus, rendering them smart structures. On the other hand, nano materials, having characteristic dimensions of less than 100 nm and that are nowadays available in particles, short or long fibres, tubes, platelets, or thin films forms, were developed for enhancing passive structural materials performance; for example, for increasing their thermal and electrical conductivities or/and their mechanical (mainly elastic) resistance or stiffness. They were mostly used as reinforcements of such materials. While the nanotechnology in engineering is being developed mostly independently from smart materials, a recent growing tendency is to combine nano and smart materials in order to enhance synergistically the resulting smart structures performance and reach new designs or/and applications. This is, for example, the main aim of the present International Journal for Smart and Nano Materials (IJSNM), and of joining the series of International Conference on Smart Materials and Nanotechnology in Engineering (SMN) with that of International Conference on Smart Materials and Structures (CANSMART) in 2015, or with that of the ECCOMAS Thematic Conference on Smart Structures and Materials (SMART) in 2017. By merging such events, cross-fertilization of multidisciplinary – driven inspiration ideas and multi-research communities’ cross-dialogue are reached.

The present IJSNM special issue spans volume 9's issue 1 [1-4] and issue 2 [5-8]; it contains 8 papers [1-8] that were extended and revised (some of them twice) according to 3 anonymous and independent peer reviewers’ reports. They were spontaneously submitted following an open call to the participants of the joint 8th SMART and 6th SMN held in Madrid (Spain) from 5 to 8 June 2017. The latter attracted 250 submissions from 36 countries representing 5 continents, among which 220 ones were presented in 7 plenary lectures (PL), 4 keynote lectures (KL), 16 mini-symposia (MS) that were organized by experts in their related research fields, 1 special session (SS), 3 general sessions (GS) and 1 Poster session [9]. This major event, in the joined fields of ‘smart structures, materials and nano technology in engineering’, was supported by several academic and research institutions as well as by industrial companies and research centres. It was closed by a technical visit to a ‘design and manufacturing of aero-structures and components’ supplier of renowned international (multi-national) aircraft manufacturers. Hereafter are briefly described the 8 papers of the present IJSNM special issue spanning volume 9's issue 1 [1-4] and issue 2 [5-8].

The first paper [1] was presented in ‘MS07: Advanced finite element models for smart structures’; it provides an electromechanical analysis of composite and sandwich multi-layered structures by shell elements with node-dependent kinematics. The second one [2], presented in ‘MS05: Multifunctional structures with integrated piezoelectric elements’, introduces the Ritz sub-laminate generalized unified formulation approach for piezoelectric composite plates. The third contribution [3], presented in ‘SS: CRC/TR 39 PT-PIESA project’ on lightweight design by integrating functions addresses, numerically and experimentally, the monitoring concept for structural integration of PZT fibre arrays in metal sheets. The fourth contribution [4] is a focused review on the less known and investigated research topic of field-dependent nonlinear piezoelectricity. While the 5th paper [5], on finite element analysis scattering of surface acoustic wave (SAW) bandpass filter on Barium Titanate thin film in cubic phase, was not presented in SMART/SMN 2017, it represents well its ‘MS10: SAW passive and wireless sensors for structural health monitoring applications’. Beside above SS and MS05, the tendency of embedding smart materials, instead of classically surface-bonding them on host structures, was the focus of ‘GS2: Embedded smart materials technology’ which sample representative is the 6th contribution [6] on the temperature and strain registration by fibre optic strain sensor in the polymer composite materials manufacturing. The 7th paper [7], presented in above MS05, describes an approach to determine shunt circuits parameters for vibration damping. The last (8th) contribution [8] is a sample of the synergy between SMART and SMN joined events as it discusses morphology- and ion-size induced actuation of Carbon Nano Tube (CNT) architectures.

As can be noticed from the previous section, this issue presents few smart and nano materials behaviour and response for smart structures and nanotechnology in engineering applications. We hope that this ‘picture’ from SMART and SMN 2017 brings new knowledge and ideas to their respective research communities and contributes to open minds and widen research interests of IJSNM readers. As a closure, we are very thankful to the authors for their very interesting contributions and to the reviewers for their meticulous reports. Besides, the organizers of SMART and SMN 2017 are very thankful to the editor-in-chief, Professor Jinsong Leng, and to the publisher, Sage Publications, for their supports to these events by dedicating the present special issue (spanning volume 9's issue 1 [1-4] and issue 2 [5-8]) to sample contributions from those presented therein and by publishing it in open access format with weaved Articles Processing Charges (APC).

Disclosure statement

No potential conflict of interest was reported by the author.