This review examines the state‐of‐the‐art sensors and sensing technologies employed for structural health monitoring (SHM) in aerospace composites, highlighting the shift from conventional nondestructive evaluation techniques to real‐time monitoring systems. The review discusses the challenges associated with composite materials, such as their anisotropic nature and susceptibility to invisible damage, and how these challenges have driven the improvement of SHM techniques. Fiber‐optic sensors, including interferometric, distributed, and grating‐based sensors, are analyzed for their high sensitivity and multiplexing capabilities, making them suitable for distributed sensing applications. Piezoelectric sensors are evaluated for their effectiveness in both active and passive damage detection methods. At the same time, piezoresistive self‐sensing systems are explored for their potential to integrate sensing directly into composite materials. The review also addresses the challenges encountered in implementing SHM systems. It suggests solutions like protective coatings, advanced data processing algorithms, and modular system design to overcome these challenges. In conclusion, this review provides a comprehensive overview of the current SHM technologies for aerospace composites, underscoring the need for sustained research and development to improve sensor technology, expand data processing capabilities, and ensure seamless integration with aircraft systems, thus contributing to the safety and efficiency of aerospace operations.

In this work, the effect of ply stacking sequence of carbon/epoxy laminates subjected to flexural, tensile and impact loading was investigated. Five laminates with different stacking configurations were produced using the hand-laying-up technique. This includes a unidirectional laminate, cross-ply laminates, and quasi-isotropic laminates. Following the autoclave curing process, the responses of the composites to bending, tension and impact force were determined according to ASTM standards, and their corresponding strength, stiffness as well as impact energy were evaluated. Likewise, the flexural failure mode associated with each laminate was characterised using an optical microscope. The unidirectional laminates have higher flexural and tensile strength compared to the cross-ply and quasi-isotropic laminates. Moreover, as a result of material symmetry, the flexural and tensile modulus of symmetric cross-ply laminate improved by 59.5% and 3.97% compared to the unsymmetric counterpart. Furthermore, the quasi-isotropic laminates with absorption energy of 116.2 kJ/m² and 115.12 kJ/m², respectively have higher impact resistance compared to other samples.

This review examines various studies on reducing tensile stresses generated in a polymer matrix composite without increasing the mass or dimension of the material. The sources of residual stresses and their impacts on the developed composite were identified, and the different techniques used in limiting residual stresses were also discussed. Furthermore, the review elaborates on fibre-prestressing techniques based on elastically (EPPMC) and viscoelastically (VPPMC) prestressed polymer matrix composites, while advantages and limitations associated with EPPMC and VPPMC methods are also explained. The report shows that tensile residual stresses are induced in a polymer matrix composite during production as a result of unequal expansion, moisture absorption and chemical shrinkage; their manifestations have detrimental effects on the mechanical properties of the polymer composite. Both EPPMC and VPPMC have great influence in reducing residual stresses in the polymer matrix and thereby improving the mechanical properties of composite materials. The reports from this study provide some basis for selecting a suitable technique for prestressing as well as measuring residual stresses in composite materials.

The presented study focuses on measuring volume changes in elastomeric materials using digital image correlation (DIC), specifically the 2D DIC universal system and the 2D DIC video-extensometer directly implemented to the universal testing machine. Optical measurement methods were applied in twodimensional (2D) configurations during the mechanical testing of dumbbell-shaped test specimens under uniaxial tension. The measured data were used to determine the dependencies of the bulk modulus and Poisson's ratio on the strain. The dependencies obtained by both methods correspond to the model behavior of rubber-like materials. Compared to the 2D DIC implemented video-extensometer, the 2D DIC universal system provides a tool for measuring transverse and longitudinal strain, and a wide range of post-processing options, including change of the input parameters, settings, or calculation relations.

Laminar fibre-reinforced polymer composites have become essential engineering materials across aerospace, automotive, energy, and structural applications due to their high specific strength, durability, and design flexibility. Among available manufacturing routes, compression molding is widely used for high-rate production of such composites, offering advantages in material efficiency and near-net-shape fabrication; however, despite its industrial maturity, the process remains largely governed by empirical, open-loop control strategies, with limited in-situ visibility of evolving material states within closed molds, which leads to variability in consolidation quality, defect formation, extended cycle times, and increased energy consumption, particularly for complex laminate architectures. This review examines the role of optical, photonic, and laser-based technologies in enabling real-time monitoring and control of compression molding processes, where fundamental light-matter interaction principles underlying infrared thermography, spectroscopic sensing, interferometry, and fiber-optic techniques are analyzed with respect to their ability to non-intrusively access key state variables including temperature distribution, degree of cure, deformation, and strain under industrial processing conditions, while laser-based energy delivery is evaluated as a controllable and spatially selective actuation mechanism capable of directly influencing resin rheology, curing kinetics, and consolidation behavior. The synthesis of the reviewed literature demonstrates that optical signals provide physically grounded, high-resolution observables of internal process states that are inaccessible to conventional contact-based sensors, thereby enabling real-time estimation of thermochemical and mechanical evolution within the laminate, and that integrating photonic sensing with laser-based actuation within a closed-loop control architecture enables dynamic regulation of heat transfer, cure progression, and consolidation pressure in response to evolving material conditions, systematically reducing process uncertainty, mitigating defect formation mechanisms such as porosity and uneven curing, and enabling significant reductions in cycle time and energy consumption compared to conventional open-loop processing. The findings of this study provide a comprehensive understanding of how photonic technologies can transform compression moulding from a conservative, empirically driven process into an intelligent, state-aware manufacturing system, thereby supporting improved process robustness, scalability, and industrial deployment of high-performance composite structures across demanding engineering applications.