Additive Manufacturing of Smart Composite Structures Based on Flexinol Wires

3D printing of a composite structure with shape memory materials requires a special approach to the subject, at the stage of the design and printing process. This paper presents the design steps during the development of a 3D-printed composite structure with shape memory material. The connection points between the SMA fibers and the printer filament are developed in the MATLAB environment. Finite element method is used to simulate the shortening of the shape memory material under the influence of temperature and its effect on the printed polymer material is presented. In the MATLAB environment, evolutionary algorithms were used to determine the shape of the SMA fiber alignment. This work demonstrates the use of shape memory effect in 3D printed smart composite structures, where the component takes a predetermined shape. The structure obtained as a result of such printing changes with the heat generated by the current voltage, making it the desired fourth dimension.

Controllable Bistable Smart Composite Structures Driven by Liquid Crystal Elastomer

In this article, we proposed a new way to achieve monostable and bistable characteristics of composite layers based on liquid crystal elastomer (LCE). A smart trilayer composite structure is fabricated using LCE and acrylic elastomer, which can have several morphologies. It keeps flat at room temperature and can deform into a monostable saddle or bistable cylinder surface in response to simple temperature changes. The reversible deformation can be controlled through two parameters including geometrical size and actuation strain. The LCE can be programmed to generate different actuation strains by different formulas during synthesis or different mechanical stretches during UV radiation. The deformed morphology for different sample sizes and actuation strain is calculated using Finite element simulation. By comparison with the experimental results, we confirm that the phenomena can be captured through numerical simulations. Furthermore, to have a quantitative understanding, we use numerical simulation to calculate the deformation of the composite structure by tuning these two parameters and give a morphological portrait illustrating the relationship between the deformed shape and control parameters.

Vibration control of smart composite structures using shunted piezoelectric systems and neuro-fuzzy techniques

Shunt piezoelectric circuits can be used in several combinations for passive control of smart structures. Resonant shunt circuits with resistors and inductors can control resonant frequencies, by consuming the energy produced from vibrations by passing it to electric components. Such systems are very efficient for single-mode problems; however, when it comes to multi-mode control, their performance drastically deteriorates. The purpose of the present study is the development of optimized resonant shunt piezoelectric circuits, along with an intelligent control system based on adaptive neuro-fuzzy techniques, for vibration suppression of smart composite structures. Shunt circuits are pre-tuned to the first four eigenfrequencies and a neuro-fuzzy control system is developed and used for the activation of the suitable shunt circuit, each time, providing the necessary adaptivity to the whole system.