The stochastic microstructure of recycled carbon fibre-reinforced composites poses significant challenges for process optimization and performance prediction, due to the disparity in scales between fibre diameter and fibre agglomerates size. This study establishes a comprehensive quantitative characterization framework to evaluate the microstructural evolution of recycled carbon fibre thermoplastic tapes processed under two distinct melt-compounding regimes with contrasting processing conditions. Utilizing a deep learning-based EfficientNet-B4 model and computer vision for robust fibre segmentation, we analysed the interplay between fibre morphology, orientation, and dispersion on large-field high-resolution micrographs. A novel quantitative approach revealed microstructural notions, hard to detect otherwise, and uncovered a critical trade-off governed by shear mixing history: while a shorter processing scenario preserved fibre length (>600μm), it resulted in a planar-random orientation state driven by the tumbling of large aggregates. Conversely, the longer processing scenario induced significant fibre fragmentation but facilitated a transition towards uniaxial alignment. To identify these changes in microstructure, novel homogenization factors (Cluster Prevalence Indicator (CPI) μ and Intra-Cluster Density Indicator (IDI) κ) and a Collective Similarity Index (CSI) were introduced. These metrics demonstrated that extended mixing transitions the material from a state dominated by volumetrically large, internally dense super-clusters to a locally dispersed microstructure, without altering the invariant global spatial periodicity (d^∗≈260μm). Furthermore, a comparative evaluation of statistical descriptors highlighted that while conventional topological metrics (e.g., Voronoi statistics) proved insensitive to processing variations, the proposed cluster-based metrics and eigenvalue-based orientation tensors successfully captured the structural nuances. This framework provides essential methods for tailoring the processing-structure relationships in recycled discontinuous fibre composites.

Although conventional actuators like piezoelectric and electrostrictive are efficient, but they required hard wiring, which contaminates the control signal and adds to the weight of the structure. The current study presents a wireless control strategy using photostrictive actuators. Owing to the fortunate combination of photovoltaic effect and converse piezoelectric effect, a photostrictive actuator can generate mechanical strain, when irradiated with light intensity. Limited choices of photostrictive material with high electromechanical coupling coefficient give the motivation to design photostrictive composites. The finite element-based formulation incorporating fuzzy logic controller is employed to study the active vibration control response of cantilever structure when equipped with photostrictive composite actuator. A parametric study has been carried out to study the influence of inclusion's volume fraction on wireless active vibration control of the structure. Control merits have been defined to compare the control performance of different composites. It is found that particulate composites are the better choice for lightweight structure and fiber composites are better if there is no weight constraint.

A model for numerical homogenization of triply periodic minimal surfaces (TPMS) based on electrostrictive composites is presented. This electrostrictive composite consists of TPMS (a three-dimensional continuous structure) implanted in a soft non-electrostrictive matrix. A representative volume element (RVE)-based approach is used to homogenize the electrostrictive composites and determine all the effective electrostrictive, mechanical, and electrical coefficients. Finite element formulation is employed to solve the nonlinear electrostrictive constitutive equations. Special attention is paid to designing the boundary conditions that permit the fast calculation based on simulations of overall deformation-induced due to mechanical and electrical loads. Interestingly, the value of the effective electrostrictive coefficient of the composite surpasses that of the inclusion Pb (mg_1/3Nb_2/3)O₃-PbTO₃-BaTiO₃ (PMN-PT-BT), even though the matrix is non-electrostrictive due to the additional flexibility imparted by the matrix. This electrostrictive response of TPMS-based composite is independent of the type of TPMS structures used. It is prudent to say that these composites will find their place in practical application owing to their salient features of more flexibility and high electrostrictive coefficient.