In this paper, six types of carbon/glass hybrid triaxial woven fabric composite laminates with different carbon/glass mixing ratios were prepared using carbon fiber unidirectional fabrics and carbon fiber, glass fiber and carbon/glass hybrid triaxial woven fabrics. The impact energies of 18 J and 28 J were chosen to carry out low-velocity impact experiments on these six kinds of composite laminates. The surface damage on the front and back sides of the impact was obtained by visual measurement, and the overall damage area inside the specimen was obtained using ultrasonic C-scanning equipment, which was combined with the impact response curves to analyze the damage mechanism of the impact process of carbon/glass hybrid triaxial woven fabric composite laminates. The results show that at low impact energy, the maximum displacement growth during the impact of U_C6 (TG) is the largest, with a growth value of 11.4%, and the absorbed energy of U_C6 (TC) is the largest, with an enhancement of 7.6%; at high impact energy, the maximum displacement growth during the impact of U_C6 (TG) is the largest, with a growth value of 15.9%, and the absorbed energy of U_C6 (TCCG) is the largest, with an enhancement of 33.4%. Two damage patterns, ellipsoid-like and circular-like, existed in carbon/glass hybrid triaxial woven fabric composite laminates with 90° direction as the long axis.

To improve the flame retardancy of polyurea (PUA)-based composite materials, this study selected modified black phosphorus nanosheets and incorporated them into the PUA system to prepare modified black phosphorus reinforced PUA composites. Four different PUA specimens were prepared: pure PUA, BP/PUA with 1wt% black phosphorus (BP) nanosheets, CS-BP/PUA with 1wt% chitosan-modified black phosphorus (CS-BP) nanosheets, and MB-CS@BP/PUA with 1wt% chitosan and melamine borate (MB) modified black phosphorus (MB-CS@BP) nanosheets. The flame retardancy, combustion behavior, and mechanical properties of these four PUA specimens were compared using vertical combustion tests, cone calorimetry, tensile tests, and Charpy impact tests. The experimental results demonstrate that the addition of MB-CS@BP nanosheets significantly improves the flame retardancy of PUA. Compared to the BP and CS-BP nanosheets, the MB-CS@BP/PUA composite exhibits better combustion behavior and the best flame retardant performance. The incorporation of modified black phosphorus nanosheets MB-CS@BP also effectively enhances the tensile strength of PUA, with an increase of 36.7% compared to pure PUA. Under low-speed impact conditions, the MB-CS@BP/PUA composite shows a 41.40% improvement in impact strength when used as a protective coating on aluminum alloy compared to uncoated aluminum alloy.

SiC/SiC composites represent one of the primary long-term objectives for accident-tolerant fuel cladding in pressurized water reactor (PWR) nuclear power plants. To establish relevant testing capabilities and acquire phased mechanical property data, shortened specimens extracted from meter-length tubular materials were employed to conduct axial tensile and internal pressure burst tests on SiC/SiC composite cladding tubes at ambient temperature. Experimental results demonstrate that the SiC/SiC composite cladding tubes exhibit similar “quasi-plastic” stress-strain behavior under both stress states, characterized by progressive failure mechanisms. The tubes fabricated with 45° fiber orientation relative to the tube axis demonstrate comparable axial and hoop strengths, achieving the objective of balanced mechanical properties in both directions. Mechanical property testing of parallel samples from different production batches shows acceptably small variations, indicating that the current manufacturing process can reliably produce meter-length tubes with satisfactory uniformity in axial mechanical properties.

Large-tow carbon fiber reinforced plastics (CFRP) hold significant promise for various applications, attributed to their exceptional cost-effectiveness and exceptional performance. This study delves into the impact of hygrothermal environments on the tensile and compressive capabilities of plain-woven large-tow CFRP, accompanied by an in-depth analysis of its damage patterns and failure mechanisms. Utilizing 48K plain-woven large-tow carbon fiber prepregs, two types of laminates, namely [0]₄ and [45/0/-45/90]_S, were crafted. These laminates were subjected to tensile and compressive tests after being exposed to room-temperature dry and elevated temperature wet conditions for 14 days. The findings reveal a substantial decline in the compressive properties of large-tow CFRP following hygrothermal treatment. Scanning electron microscopy (SEM) was utilized to scrutinize the fracture morphologies. A dual-perspective analysis, encompassing both macroscopic and microscopic viewpoints, was conducted to elucidate the failure modes and mechanisms of the material. It was observed that the degradation of the resin matrix after hygrothermal treatment weakened both the fiber-matrix interface and the orthogonal woven interface, ultimately altering the failure modes of large-tow CFRP and compromising its mechanical properties.

In this paper, the minimal surface Gyroid structure ceramic skeleton with volume fraction of 30% was prepared by stereo lithography apparatus (SLA) additive manufacturing, and the interpenetrating Al₂O₃/Al composite was prepared by metal infiltration. The compressive properties of the Gyroid surface Al₂O₃/Al interpenetrating composites were compared with those of the honeycomb Al₂O₃/Al interpenetrating composites. The fracture cross sections of the composites were observed by scanning electron microscopy (SEM), and the compressive failure mechanism of the composites was analyzed. The experimental results show that the compressive failure of the two structural composites mainly occurs at the joint position of the ceramic skeleton and the ceramic-metal interface, and the overall shear angle is 45°. The Gyroid curved structural composite has higher strength and ductility than the honeycomb structural composite due to its smooth and regular topological structure resulting in lower local stress concentration. The ultimate compressive strength of the Gyroid curved structural composite is 236 MPa, which is 3.4 times that of the honeycomb structure.

In order to prevent air entrapment in the spacecraft, the honeycomb wall of composite honeycombs needs to be perforated when used. Therefore, the influence of the perforation on the equivalent modulus of the honeycomb needs to be considered in the simulation calculation, and a theoretical prediction method for the equivalent modulus of the composite honeycomb with perforations needs to be established. In this paper, the theoretical prediction formula for the equivalent flat compression modulus of the composite honeycomb with perforations is established based on the stress distribution formula of the anisotropic perforated plate under in-plane tensile and compressive loads. The theoretical prediction formula for the out-of-plane shear modulus of the composite honeycomb with perforations is established by the semi-analytical method. An approximate calculation method for the equivalent bending stiffness of the perforated plate is given and a theoretical prediction formula for the equivalent in-plane modulus of the composite honeycomb with perforations is established. In order to verify the validity of the theoretical model, the corresponding finite element analysis was carried out. The results show that the theoretical prediction results of the modulus under different apertures are in good agreement with the numerical simulation calculation results. The reliability of the theoretical model is verified. This paper takes the main bearing plate of a typical remote sensor as the application object, establishes a refined model and a three-dimensional solid equivalent model, and conducts modal analysis. The results show that the frequencies and vibration modes calculated by the two modeling methods are close, the maximum error is up to 4.4%. The research results of this article can provide reference for equivalent modeling of honeycomb with open cells in composite materials in engineering.

High-performance continuous fiber reinforced thermoplastic resin-based composites possess properties such as high toughness, fatigue resistance, impact resistance, and reprocessable capabilities. These characteristics allow them to address the shortcomings of traditional thermosetting composites, which includes insufficient toughness, tendency to delaminate under low-speed impacts, and low fatigue limit. In this study, using AC8201 resin as the matrix and domestic high-strength glass fiber S6C10 as the reinforcing material, a continuous high-strength glass fiber reinforced polyether-ether-ketone thermoplastic prepreg with the grade of S6C10/AC8201 was successfully prepared by the suspension hot melt method. The appearance of the prepreg was uniform and flat without dry yarn, and the resin content of the prepreg was 24.8% with excellent physical properties and processability. Utilizing thermo press molding technology, composite laminates made from S6C10/AC8201 had been fabricated. These laminates featured even thickness distribution, no dry fibers, and exhibited outstanding mechanical performance and fatigue resistance. Specifically, the bending strength of the developed composite material reached 1 818 MPa, representing 13.6% improvement compared to that of TC1200 prepreg. Furthermore, the 0° tensile fatigue limit strength was measured at 490 MPa, showcasing a significant enhancement of 21.3% over that of thermoset S6-reinforced high-temperature epoxy composites.

Carbon fiber composite materials have poor resistance to high-velocity impact, which to some extent hinders further expansion of application, so the hybrid design of carbon fiber and other fibers in composite materials is an effective measure to improve the comprehensive performance of composite materials. The investigation of static and dynamic mechanical properties exhibits C/EP possesses better static mechanical properties, while F12/EP has better dynamic mechanical properties. Based on automated fiber placement, structure design and the control of mass ratio for aramid fiber/carbon fiber, a novel carbon/aramid fiber hybrid composite combined with excellent mechanical property and high-velocity impact resistance has been prepared. The preferred mass percentage of aramid fiber for the hybrid composites is 35%~55%. The morphology analysis and simulation analysis for the sample after impact, the damage area of front plate and back plate for C/EP is obviously smaller than that for F12/EP, which indicates that F12/EP possesses better ability for impact energy dissipation, resulting in a higher criticalpenetration velocity.

The sewing device was designed and optimized with the objective of improving the rate of successful sewing in carbon fiber composite materials. This paper investigates the dynamic characteristics of the joint clearance of the needle driver mechanism in a sewing device. The joint and dynamic model of the needle driver mechanism have been developed, and the contact force models for the three clearance-containing rotary joint have been evaluated. A dynamic simulation of the clearance model is conducted using MATLAB software to examine the influence of three contact force models on the dynamic performance of the needle driver mechanism. Subsequently, a physical sewing device is constructed for the purpose of conducting an experimental analysis. The results of the study show that, the hydrodynamic contact force model is selected for analysis of the clearance-containing rotary joint. This approach results in a closer alignment between the dynamic characteristics of the mechanism and that of the ideal rotary joint, which in turn reduces the vibration of the needle driver mechanism, thereby increasing the rate of successful sewing in carbon fiber composite materials and optimizing the sewing stitches. Thus, it is demonstrated that the contact force model as well as the mechanism design meets the requirements of stitched carbon fiber composite materials.

Delamination damage is one of the common damage in composite materials, and it will gradually expand with the extension of working time, which will seriously weaken the strength and stability of composite materials. At the same time, the delamination damage at different interfaces will also cause various mechanical changes to different degrees. Therefore, it is of great significance for the overall safety of the structure to effectively identify, locate and expand monitoring it. In this paper, a Lamb wave-based ToF delamination damage monitoring method is proposed. By comparing and analyzing the Lamb wave ToF differences between the upper and lower surfaces of composite laminates, the damage interface of composite laminates with an initial delamination damage is located, and the delamination damage expansion at different interfaces is continuously monitored online. Firstly, the principle of Lamb wave monitoring delamination damage is studied. Secondly, the relationship between the depth and length of the delamination damage interface and the propagation speed of Lamb waves in the structure was established, and the theoretical basis for the location and extension monitoring of the delamination damage interface was obtained. Finally, the effectiveness of the proposed method was verified by finite element simulation. The simulation results show that the shallower the delamination damage interface is from the laminate surface, the more significant the Lamb wave signal delay, and the greater the difference in signal time between the upper and lower surfaces, moreover, the signal delay is linearly related to the increase of delamination damage length.

The bonded interface of Titanium alloy/ethylene propylene diene monomer (EPDM) is one of the crucial interfaces in the solid rocket engine shell. In this paper, the simulation performance parameters were obtained based on the fracture toughness analysis test of mode Ⅰ and Ⅱ interface, and the failure criterion parameters were obtained through shear and peel tests. The finite element model of the double cantilever beam (DCB) specimen was established, and the contact of bonding surface was defined with the bilinear cohesive zone model. The degree of coincidence between the simulation and the experimental curve was calculated by formula, and the optimal value of the function was obtained by artificial neural network in combination with genetic algorithm (GA-ANN), simulated annealing (SA-ANN), and MATLAB in combination with genetic algorithm (GA-MAT) and simulated annealing (SA-MAT). Thus, the precise value of the interface modulus was obtained. Based on the experimental test results, numerical simulation was used as a reverse engineering tool, optimization calculation was used as an analysis method, and the precise value of the Ti/EPDM bonding interface performance parameters was obtained by combining testing, simulation, and calculation. The results are verified based on the test, and are in good agreement, providing a criterion for evaluating the environmental adaptability of the combustion chamber shell interface structure.

Electrochemical anodic oxidation is an important method for enhancing the surface activity of high-modulus carbon fibers. To investigate the influence of electrolyte oxidizability on the surface treatment performance, five electrolytes with different oxidation potentials (NaOH, NH₄HCO₃, H₂SO₄, NaNO₂, and HNO₃) were employed to modify polyacrylonitrile-based high-modulus carbon fibers via anodic oxidation. The effects of electrolyte oxidizability on the physicochemical surface structure and interfacial properties of the fibers were systematically analyzed. The results show that with increasing oxidizability, the graphite layer expansion becomes more pronounced, the content of sp³ carbon structures and oxygen-containing functional groups increases, and the surface chemical reactivity is significantly enhanced. This study reveals the key role of electrolyte oxidizability in the anodic oxidation process of carbon fibers and provides a theoretical basis for optimizing the surface structure of high-modulus carbon fibers.

The satellite mounting plate of carbon fiber composite has a special internal rib grid structure. In order to solve the problem of difficulty in forming large-size closed-cavity structural parts using existing composite material forming process methods, this work designs a composite water-soluble core mold with flexible expansion skin-core characteristics, and proposes a process method for co-curing composite material internal rib grid closed-cavity structure based on the composite core mold, and verifies the rationality of the process strategy through typical part process tests. The preparation of the satellite mounting plate product was finally realized by using a laminate autoclave and thermal expansion process in conjunction with co-curing forming tooling. Compared with the traditional partition pre-pressing-secondary bonding forming process, the co-curing forming scheme proposed in this paper greatly reduces the manufacturing cost and process complexity, without fastener connection and secondary bonding, and the structural continuity, overall mechanical properties and inner cavity cleanliness of the satellite mounting plate are significantly improved. The product has passed the bending, flat pressing, vibration and thermal environment assessments.

A new type of aluminium-framed composite sandwich slab was designed to meet the high load-bearing capacity requirements of plateau-type dismantled storage devices. Experimental, theoretical and finite element methods were used to study the mechanical behavior of the aluminium frame composite sandwich slab. The counterweight was used to simulate the response of the aluminium-framed composite sandwich slab under the wind load,and the mid-span deflection value of the aluminium-framed composite sandwich slab was 4.74 mm under the maximum primary load (2.46 kN/m²), which was 85.87% of the deflection limit of 5.52 mm(l/400)in the normal service limit range. The mid-span deflection formula was derived of the aluminium frame composite sandwich slad by the classical theory of composite sandwich structure, and the theoretical calculated value was slightly larger than the experimental value, with a maximum error of 9.90%, which matched well in general. The 3D model of aluminium-framed composite sandwich slab was established by ANSYS/Multiphysics software and the finite element analysis was carried out to simulate the response of aluminium frame composite sandwich slab under the wind load. The finite element simulation result is slightly smaller than the experimental result, the results of finite element analysis are in good agreement with the experimental data. The 3D model of the composite sandwich panel was used for finite element parametric analysis, with aluminium frame, lattice webs and increased panel thickness, which was found that the mid-span deflection was reduced by 57.43%, 78.05% and 30.16% under the maximum primary loading.

When designing repair plans for composite honeycomb panel structures, the influence of hygrothermal effects on their vibration characteristics is generally not considered. Reasonable repair parameter design can effectively restore the natural frequency of the repaired honeycomb panel. Through finite element simulation and modal testing, the variation law of the natural frequency of carbon fiber epoxy resin/aramid paper honeycomb board repaired by single-sided patching with different repair parameters under the influence of damp heat was comprehensively analyzed. A finite element model of single-sided patch repair of honeycomb panels was established using segmented shear deformation theory and combined with wet heat equivalent theory, and the influence of repair parameters on the natural frequency of repaired honeycomb panels under different wet heat conditions was analyzed. The results indicate that when the number of patch layers is the same as the number of patch layers on the panel to be repaired, the natural frequency of the repaired panel is less affected by hygrothermal conditions, while the effect is greater when there are too few or too many patch layers. When the overlap length of the patch is 0.5~1 times the damage diameter, the natural frequency of the repair board is less affected by hygrothermal, and when the overlap length further increases, it is more significantly affected by hygrothermal. The reduction of natural frequency of repaired honeycomb panels is more significant in wet environments than in thermal environments, and the combined effect of hygrothermal has a greater impact on the natural frequency of composite honeycomb repair panels than single moisture and heat effects.

In response to the issue of beam failure and insufficient energy dissipation in GFRP beam column joints with sleeve connections under cyclic loading, the failure mode and seismic performance of the joints were studied based on experimental study. The improvement of seismic performance of the joints after adding or not add adhesives and influence of different kind of adhesives was analyzed and compared. On the basis of sleeve connection, this paper provides four groups of GFRP beam column joints: non-adhesive, flexible adhesive, rigid adhesive, and mix adhesive, and conducted low cycle repeated loading tests to study the influence of adhesives with different strengths on the seismic performance of the joints. The results showed that the addition of flexible adhesive increased the energy consumption of joints by approximately 97.19%, compared to non-adhesive. While the addition of rigid adhesive increased the energy consumption of joints by approximately 298.86%. Flexible adhesive is more prone to cracking compared to rigid adhesive, and after the adhesive is failed, the joint performance to approach that of a non-adhesive group. The results of rigid adhesive and mix adhesive are similar, indicated that the effect of adhesives with different characteristics on the side of the sleeve is not significantly different. There is no cracks in the rigid adhesive group, and the failure mode is sleeve buckling, with the beam and column intact. It is recommended to add rigid adhesive in the sleeve connection to improve the seismic performance of the joints.

SiC_f/SiC composite materials exhibit characteristics such as lightweight, low density, excellent high-temperature stability, superior mechanical properties, outstanding chemical stability, and high wear resistance, making them ideal for hot-section components in aero-engines. This paper primarily introduces the current development status of SiC fibers, the fabrication processes and properties of SiC_f/SiC composites, and the application progress of SiC_f/SiC composites in aero-engines. It further analyzes the challenges currently faced in the development of SiC_f/SiC composites and proposes key priorities for their future advancement.

In response to the growing demand for automotive lightweighting, thermoplastic composites have demonstrated broad application potential in the automotive industry due to their excellent mechanical properties, low-density characteristics, and favorable processing adaptability. This article reviews the practical applications of thermoplastic composites in automotive structural components, interior trim parts, exterior panels, and load-bearing components. Meanwhile, to address current challenges such as high costs, complex forming processes, and immature recycling technologies, feasible engineering solutions are proposed. With advancements in polymer material modification technologies and intelligent manufacturing, thermoplastic composites will play an increasingly important role in automotive lightweighting, driving the transformation and upgrading of the automotive industry toward green and low-carbon development.