As an important method for efficient manufacturing of advanced composites, Automated Fiber Placement (AFP) technology has exhibited significant advantages in the production of large and complex curved structures in the aerospace field. However, due to the limitations in equipment precision, material characteristics, and structural complexity, various types of layup defects are prone to occur during the AFP process, which severely affect the structural performance and service reliability. Accordingly, research on key technologies such as defect detection, characterization, and process optimization has become essential for improving AFP manufacturing quality. This study briefly discusses the foundational research pertaining to typical defects in the AFP processes. Current research progress in defect detection, characterization, and process parameter optimization in AFP technology is systematically reviewed. Existing limitations in detection, characterization, and process optimization methods for AFP defects are summarized, along with future research directions. Based on the findings of the relevant research, a closed-loop technical framework for composite manufacturing quality control is proposed, providing a systematic reference for achieving high-quality, high-reliability, and high-intelligent AFP manufacturing of composites.

With the continuous appearance and expansion of high-strength hydrogels in emerging fields such as industry, medicine, and green development, the synthesis and application of high-strength hydrogels have developed dramatically and achieved remarkable results from the aspects of raw materials, preparation methods, and reinforcement mechanisms. However, there is still a lack of systematic reviews on high-strength hydrogels. Herein, we first discuss the advantages of natural and synthetic materials, and the characteristics of high-strength hydrogels prepared from different raw materials; we then expound on the influence mechanism of physical interactions or chemical bonds on the strength of the hydrogel from three aspects: physical cross-linking, chemical cross-linking, and dynamic chemical cross-linking; at last, we systematically expound the strengthening strategies, including double network/multi-network, nanocomposite, topology, supramolecular polymerization, and characteristics and strengthening mechanisms of such high-strength hydrogels. In addition, based on the development status of high-strength hydrogels, we combined the application requirements and the existing drawbacks of high-strength hydrogels to propose their possible development directions in the future.