Development of Liquid Diene Rubber Based Highly Deformable Interactive Fiber-Elastomer Composites

The preparation of intelligent structures for multiple smart applications such as soft-robotics, artificial limbs, etc., is a rapidly evolving research topic. In the present work, the preparation of a functional fabric, and its integration into a soft elastomeric matrix to develop an adaptive fiber-elastomer composite structure, is presented. Functional fabric, with the implementation of the shape memory effect, was combined with liquid polybutadiene rubber by means of a low-temperature vulcanization process. A detailed investigation on the crosslinking behavior of liquid polybutadiene rubber was performed to develop a rubber formulation that is capable of crosslinking liquid rubber at 75 °C, a temperature that is much lower than the phase transformation temperature of SMA wires (90–110 °C). By utilizing the unique low-temperature crosslinking protocol for liquid polybutadiene rubber, soft intelligent structures containing functional fabric were developed. The adaptive structures were successfully activated by Joule heating. The deformation behavior of the smart structures was experimentally demonstrated by reaching a 120 mm bending distance at an activation voltage of 8 V without an additional load, whereas 90 mm, 70 mm, 65 mm, 57 mm bending distances were achieved with attached weights of 5 g, 10 g, 20 g, 30 g, respectively.

Impact of Including Electronics Design on Design of Intelligent Structures: Applications to Multifunctional Structures for Attitude Control (MSAC)

Multifunctional Structures for Attitude Control (MSAC) is a new spacecraft attitude control system that utilizes deployable panels as multifunctional intelligent structures to provide both fine pointing and large slew attitude control. Previous studies introduced MSAC design and operation concepts, simulation-based design studies, and Hardware-in-the-Loop (HIL) validation of a simplified prototype. In this article, we expand the scope of design studies to include individual compliant piezo-electric actuators and associated power electronics. This advance is a step toward high-fidelity MSAC system operation, and reveals new design insights for further performance enhancement. Actuators are designed using pseudo rigid body dynamic models (PRBDMs), and are validated for steady-state and step responses against Finite Element Analysis. The drive electronics model consists of a few distinct topologies that will be used to evaluate system performance for given mechanical and control system designs. Subsequently, a high-fidelity multiphysics multibody MSAC system model, based on the validated compliant actuators and drive electronics, is developed to support implementation of MSAC Control Co-design optimization studies. This model will be used to demonstrate the impact of including the power electronics design in the Optimal Control Co-Design domain. The different control trajectories are compared for slew rates and the vibrational jitter introduced to the satellite. The results from this work will be used to realize closed-loop control trajectories that have minimal jitter introduction while providing high slew rates.

Análisis coste-beneficio de las estructuras inteligentes = Cost-benefit analysis of intelligent structures

Resumen Definimos estructura inteligente como aquella estructura dotada de unos sensores (en especial continuos y de fibra óptica), de manera que es capaz de transmitir datos de interés sobre su estado de salud (deformaciones, fisuraciones, oxidaciones, etc.). Esta tecnología puede facilitar el mantenimiento preventivo de los edificios y la gestión de su salud estructural. Por ello, un aspecto de interés necesario a analizar para saber si la tecnología es aplicable o no, es evaluar su rentabilidad. Así, el objeto de este artículo es realizar un análisis coste-beneficio de las estructuras inteligentes, estudiando por un lado cuál es el incremento de coste inicial que supone la implementación de la propuesta, y por otro lado evaluar cuál es el ahorro de dinero a lo largo del tiempo que supone la aplicación de la misma, lo que permite establecer el periodo de retorno de la inversión inicial, y a partir de qué momento se pueden esperar beneficios netos. Abstract Smart structure is defined as that structure equipped with sensors (especially continuous and composed of fiber optic), so that it is capable of transmitting data of interest about its state of health (deformations, cracks, oxidations, etc.). This technology can facilitate the preventive maintenance of buildings and the management of their structural health. Therefore, an aspect of interest necessary to analyze in order to know if the technology is applicable or not, is to evaluate its profitability. Thus, the objective of this article is to perform a cost-benefit analysis of smart structures, studying on the one hand which is the initial cost increase involved in the implementation of the proposal, and on the other hand to evaluate which is the saving of money to over the time that the application of it represents, what allows to establish the payback period of the initial investment, and from which moment you can expect net benefits.

Genetic code: Chemical Distinctions of Protein Amino Acids

In the work it is shown that 20 protein amino acids ("the canonical amino acids" within the genetic code) appear to be a whole and very symmetrical system, in many ways, all based on strict chemical distinctions from the aspect of their similarity, complexity, stereochemical and diversity types. By this, all distinctions are accompanied by specific arithmetical and algebraic regularities, including the existence of amino acid ordinal numbers from 1 to 20. The classification of amino acids into two decades (1-10 and 11-20) appears to be in a strict correspondence with the atom number balances. From the presented "ideal" and "intelligent" structures and arrangements follow the conclusions that the genetic code was complete even in prebiotic conditions (as a set of 20 canonical amino acids and the set of 2+2 pyrimidine / purine canonical bases, respectively); and the notion "evolution" of the genetic code can only mean the degree of freedom of standard genetic code, i.e. the possible exceptions and deviations from the standard genetic code. [This is the second version with minimal interventions in the text. In addition, one passage was added in front of the second star, with quoting of T. Jukes. Added is Remark 4 and a more adequate shading in the Table inside Box 2.]

Topology Optimization of Structural Systems Considering Both Compliance and Input Observability

Recent advances in flexible and wireless sensors, soft materials, and additive manufacturing, have stimulated demands for developing intelligent systems that can achieve multidisciplinary objectives (e.g., mechanical strength, thermal conductivity, state and input estimation, controllability, and others). Existing studies often decouple these objectives through sub-system level design, e.g., topology and material design for mechanical and thermal properties, and filter and sensor/actuator design for observability and controllability, assuming that the sub-systems have minimal influences to each others. To investigate the validity of this assumption, we take a unique angle at studying how the topology of the system influences both structural performance (e.g., compliance under static loads) and input observability (e.g., the error in estimating the loads). We reveal a tradeoff between these two objectives and derive the Pareto frontier with respect to the topology. This preliminary result suggests the necessity of a multiobjective formulation for designing intelligent structures, when significant tradeoffs among system objectives exist.

Genetic code: Chemical Distinctions of Protein Amino Acids

In the work it is shown that 20 protein amino acids ("the canonical amino acids" within the genetic code) appear to be a whole and very symmetrical system, in many ways, all based on strict chemical distinctions from the aspect of their similarity, complexity, stereochemical and diversity types. By this, all distinctions are accompanied by specific arithmetical and algebraic regularities, including the existence of amino acid ordinal numbers from 1 to 20. The classification of amino acids into two decades (1-10 and 11-20) appears to be in a strict correspondence with the atom number balances. From the presented "ideal" and "intelligent" structures and arrangements follow the conclusions that the genetic code was complete even in prebiotic conditions (as a set of 20 canonical amino acids and the set of 2+2 pyrimidine / purine canonical bases, respectively); and the "evolution" of the genetic code can only mean the degree of freedom of standard genetic code, i.e. the possible exceptions and deviations from the standard genetic code.