Table of Content

28 June 2026, Volume 0 Issue 6

Previous Issue   

BASIC AND MECHANICAL PERFORMANCE RESEARCH

Analysis of natural characteristics of functionally graded carbon nanotube reinforced composite conical-cylindrical shells

ZHANG Yunfeng, WU Zhihua, WANG Wenqi, TIAN Zedong

2026, 0(6):  1-9.  DOI: 10.19936/j.cnki.2096-8000.20260628.001

Asbtract ( 51 )   PDF (6531KB) ( 74 )  

References | Related Articles | Metrics

The free vibration characteristics of functional gradient carbon nanotube reinforced composite conical-cylindrical shells under arbitrary boundary conditions are investigated. The study encompasses both the uniform distribution of carbon nanotubes and four different functionally graded distribution scenarios. The effective material properties of this type of composite are obtained using a generalized mixture rule. Based on Love’s shell theory and Sanders’ shell theory, a theoretical model of the conical shell is established, and a theoretical model of the cylindrical shell is derived through a parameter degradation method. The energy function of the combined shell is presented, and arbitrary boundary conditions at the ends of the shell, as well as continuity conditions at the junctions of the sub-shells, are simulated using artificial spring techniques. The circumferential and axial displacement components of the shell are expressed using Fourier series and Chebyshev polynomials, respectively, and the Rayleigh-Ritz method is employed to formulate the vibration equations of the FG-CNTRC conical-cylindrical shell. Subsequently, the natural frequencies of the combined shell structure are computed and compared with results from previous literature and experimental findings, thereby strongly validating the reliability and effectiveness of the proposed model and methods. Through a parameter sensitivity analysis, the influence of key factors, such as circumferential wave number, thickness-to-radius ratio, radius ratio, half apex angle, and the volume fraction and distribution form of carbon nanotubes, on the inherent vibration characteristics of the FG-CNTRC conical-cylindrical shell is investigated.

Study on the interface properties of Kevlar fiber/graphene oxide hybrid toughened GFRP-Balsa sandwich structure

CAI Yuzhi, SHI Huiyuan, TANG Baijian, XU Ziheng

2026, 0(6):  10-19.  DOI: 10.19936/j.cnki.2096-8000.20260628.002

Asbtract ( 39 )   PDF (18755KB) ( 55 )  

References | Related Articles | Metrics

The study focused on GFRP-Balsa sandwich structures, conducting three-point bending tests on a total of 9 specimens of three types of sandwich beams: non-toughened, Kevlar short fiber toughened, and Kevlar short fiber combined with graphene oxide hybrid toughened. By analyzing the interfacial delamination morphology, crack propagation patterns, and strain energy release rates of the GFRP-Balsa sandwich structures, the toughening mechanisms of different methods were elucidated. Experimental results demonstrated that, compared to non-toughened specimens, the hybrid toughened specimens exhibited a 25.96% increase in critical delamination load and a 92.4% enhancement in average strain energy release rate, indicating that the hybrid toughening method significantly improves the interfacial toughness of GFRP-Balsa sandwich structures. Scanning electron microscopy images and experimental data revealed that the toughening mechanism of Kevlar fibers involves the formation of composite fiber bridging structures, while graphene oxide modifies the resin, enabling it to tightly encapsulate the hybrid fibers, thereby increasing the difficulty of interfacial delamination.

Mechanical properties test and failure mechanism analysis of pultruded carbon fiber reinforced composite

LI Yixuan, REN Hongliang, LIU Weisheng, LI Chengliang, HUANG Huixiu, LI Chuang, LI Yongfeng, ZHANG Hui

2026, 0(6):  20-27.  DOI: 10.19936/j.cnki.2096-8000.20260628.003

Asbtract ( 44 )   PDF (15632KB) ( 91 )  

References | Related Articles | Metrics

This study investigates the mechanical behavior of pultruded carbon fiber-reinforced thermosetting resin matrix composites(pultruded CFRP) under complex loading conditions. Through a series of mechanical tests combined with digital image correlation(DIC) and scanning electron microscopy(SEM), the failure mechanisms were elucidated. A three-dimensional solid element model incorporating the 3D Hashin failure criterion was employed to predict the strain field and mechanical response of pultruded CFRP under open-hole tension. The results indicate that the material exhibits significant anisotropic failure behavior under different loading directions. Both longitudinal tensile and compressive properties are markedly superior to their transverse counterparts, primarily due to the direction-dependent failure modes in pultruded composites. Under longitudinal tension, failure is dominated by fiber-matrix interfacial debonding, triggering stress redistribution and subsequent fiber brittle fracture, whereas transverse tension failure is governed by matrix-dominated fracture accompanied by interfacial debonding. Under compressive loading, longitudinal failure originates from fiber micro-buckling, while transverse failure is characterized by matrix shear yielding-induced interfacial debonding and localized fiber yielding. Since the fracture and yielding loads of fibers are substantially higher than those of the matrix, the longitudinal mechanical properties significantly outperform the transverse properties. In shear failure mode, the composite exhibits multiple crack propagation features, initiated by horizontal matrix cracks near the notch, which develop into multiple parallel matrix cracks along the fiber direction, ultimately leading to global failure. Additionally, the open-hole tensile strength reaches 1 246.83 MPa, demonstrating a typical fiber-matrix interfacial longitudinal splitting failure induced by hole-edge stress concentration. Numerical simulation of open-hole tension predicted the material’s failure mechanism with a deviation of 11.06%. Finally, a comparative analysis between DIC and conventional strain gauge measurements revealed discrepancies of less than 4% at all stress levels, validating the reliability of the DIC-derived full-field strain maps and stress-strain curves. This study systematically analyzes the failure mechanismsof pultruded CFRP through multiple fundamental mechanical tests, providing a theoretical basis for structural design and failure assessment under complex loading conditions.

Analysis of microstructure and properties of aluminum matrix composites with different contents of SiC+Al₂O₃ prepared by cold spraying

CHENG Qingsi, ZHANG Liheng, XIN Hongmin, ZHOU Jinhua, LI Yihan, LI Guangping

2026, 0(6):  28-37.  DOI: 10.19936/j.cnki.2096-8000.20260628.004

Asbtract ( 25 )   PDF (32580KB) ( 36 )  

References | Related Articles | Metrics

The addition of ceramic phases to aluminum matrix composites is an effective method to enhance their properties. In this study, ceramic particle-reinforced aluminum matrix composites were prepared using cold spray technology, with the ceramic particles being an equal proportion mixture of SiC and Al₂O₃. The total ceramic content was set at 15wt%, 30wt%, and 45wt%, respectively. Subsequently, the cross-sectional morphology, particle content, bonding strength, tensile strength, and hardness of the deposits were analyzed. Microstructural analysis revealed that as the theoretical content of ceramic particles increased, their actual proportion in the deposits rose from 11% to 23%. However, when the theoretical content reached 45wt%, issues such as particle agglomeration and weakened interfacial bonding were observed in the deposits, while the porosity increased from 1.12% to 1.23%. Mechanical tests showed a non-monotonic trend in microhardness(107.6 HV → 106.2 HV → 113.4 HV), while bonding strength and tensile strength improved to 48.38 MPa and 156.81 MPa, respectively. However, the high-content coating demonstrated significantly reduced plastic deformation capacity due to interfacial defects. Tribological tests indicated that the friction coefficient increased from 0.53 to 0.57, while wear loss decreased from 3.24 mg to 2.85 mg, revealing a synergistic wear-resistant effect of SiC and Al₂O₃. The study concludes that the low-content coating(15wt%) offers balanced overall performance, whereas the high-content coating(45wt%), despite its superior hardness and wear resistance, requires optimization of particle dispersion and interfacial bonding to mitigate fracture tendencies.

Performance evaluation of electromagnetic functional structures after damage

XING Yuming, CAO Huijie, YAO Xuefeng

2026, 0(6):  38-45.  DOI: 10.19936/j.cnki.2096-8000.20260628.005

Asbtract ( 33 )   PDF (11481KB) ( 46 )  

References | Related Articles | Metrics

Electromagnetic functional structures have both load-bearing and wave-absorbing properties, and are often used at the edge to reduce electromagnetic scattering. However, electromagnetic functional structures are susceptible to impact and even shock damage during service, which not only compromises their load-bearing performance but also significantly affects their electromagnetic properties. This study focuses on the electromagnetic functional structures. Electromagnetic simulation models were established for various conditions, including intact, penetrating damage, and skin damage. The radar cross sections under different pitch angles in the X-band were analyzed and comprehensively evaluated. By examining the electromagnetic field and power loss density distribution, the mechanism through which damage influences the radar cross section of the structure was further investigated. The results indicate that the effect of damage on the structure’s wave-absorbing performance exhibits significant frequency and angle dependence. Penetrating damage with a front-end radius of 30 mm resulted in a maximum radar cross section increase of 21.65 dB. The radar cross section of the electromagnetic functional structure increased with the size of the damage, and the adverse effects of damage were more pronounced at lower frequencies. The detrimental impact of front-end skin damage was comparable to that of front-end penetrating damage, while damage at the front end had a far greater deteriorating effect on radar cross section than damage at the middle section. For instance, under damage conditions with a radius of 20 mm, the maximum radar cross section increases caused by front-end penetrating damage and skin damage at 8 GHz were 11.67 dB and 12.00 dB, respectively, whereas the maximum radar cross section increase caused by middle-section damage was below 3.05 dB.

Viscosity analysis and quantitative testing method of phenolic resin prepreg by hot melt method

WANG Runji, ZHANG Zhongzhou, YIN Qichen, LI Yifei, YAO Yuejuan, CHEN Fei, LIUYuhong

2026, 0(6):  46-54.  DOI: 10.19936/j.cnki.2096-8000.20260628.006

Asbtract ( 29 )   PDF (10668KB) ( 39 )  

References | Related Articles | Metrics

The tackiness of prepreg is one of the key indicators in prepreg storage and composite material forming processes. Currently, there is a lack of standardized testing methods for the quantitative characterization of prepreg tackiness. In this study, a rheometer was employed as a tack-testing device to systematically investigate the effects of key process parameters such as temperature, compaction force, debonding rate, and aging on the tackiness of phenolic prepregs. The results demonstrate that the tackiness of phenolic prepregs is a function of temperature and compaction force, forming a maximum tack plateau under the synergistic mechanism of interfacial wetting and cohesion. Aging shifts the tack plateau toward higher temperature regions. Furthermore, through Arrhenius model fitting, the high-temperature tack behavior and resin-dominated debonding phenomenon of the prepreg were analyzed. The findings provide important insights for optimizing process parameters and performance in phenolic prepreg molding.

Study on the in-plane bending failure behavior of composite cross-rib structures

HUANG Bin, WANG Wenqun, ZHANG Fanchen, GAO Jincheng, HU Congli, DING Anxin

2026, 0(6):  55-64.  DOI: 10.19936/j.cnki.2096-8000.20260628.007

Asbtract ( 37 )   PDF (16687KB) ( 51 )  

References | Related Articles | Metrics

To investigate the failure behavior of glass fiber reinforced composite cross-rib structures subjected to in-plane bending loads, a combined experimental and numerical study was conducted. Three-point bending experiments are performed to characterize the progressive failure features of the structural components. Meanwhile, a multiscale numerical model incorporating the Hashin failure criterion and the cohesive zone model(CZM) is implemented in ABAQUS through the user subroutine VUMAT, enabling a systematic investigation of the overall load-carrying behavior and the failure mechanisms of key structural components.Experimental results indicate that the bending failure of the cross-rib structure exhibits a two-stage progressive damage characteristic. In the initial stage, fiber tensile fracture occurs in the central stiffener, accompanied by the initiation and propagation of interfacial debonding within the cross-rib components. The second stage is characterized by the global failure of the longitudinal rib. Numerical simulations successfully reproduce the overall trend of the load-displacement response and the key failure inflection points, showing strong agreement with experimental observations in terms of failure locations, dominant damage modes, and load-carrying capacity degradation mechanisms. Further numerical analysis reveals that interfacial damage in the L-shaped component of the cross-rib structure first initiates at the interface with the corner insert, subsequently propagates along the ply interfaces, and ultimately leads to the loss of bonding between the lower end of the L-shaped component and the main structure. Through combined experimental-numerical validation, this study provides a theoretical basis for the structural and interfacial optimization design of composite cross-rib structures.

DESIGN AND TECHNIQUE

Analysis on the pressure distribution of the roller on curved surfaces in automated fiber placement

HE Liang, XU Xiaowei, ZHU Panxing, WANG Xiaokai, LIU Jiaqi, XU Yingjie

2026, 0(6):  65-73.  DOI: 10.19936/j.cnki.2096-8000.20260628.008

Asbtract ( 26 )   PDF (18858KB) ( 35 )  

References | Related Articles | Metrics

Automated fiber placement(AFP) is one of the key automated forming technologies for achieving high-quality and cost-effective manufacturing of large-scale composite components. The formation and evolution of typical defects during the automated fiber placement process, as well as the forming quality of composite structures, are influenced by the compaction force of the compaction roller. This study systematically investigates the effects of roller hardness, mold curvature(convex/concave), and placement force on pressure distribution through a combined approach of finite element simulation and pressure-sensitive film experiments, revealing the mechanism of pressure distribution for rollers with different hardness on curved surfaces. The results indicate that increasing the roller hardness reduces the contact area and increases the maximum contact pressure, enlarging the curvature radius of the mold surface improves pressure uniformity, while increasing the placement force significantly enhances distribution homogeneity. Based on the pressure uniformity and geometric constraint, a matching principle between roller length and mold curvature is proposed, providing a theoretical foundation for optimizing fiber placement parameters and suppressing typical defects such as wrinkles.

Carbon fiber winding reinforcement/strengthening composite process for magnesium alloy tubular parts based on chunked design

LI Shuaibing, GUAN Zhiping, SONG Jiawang, WANG Guiying, REN Mingwen

2026, 0(6):  74-87.  DOI: 10.19936/j.cnki.2096-8000.20260628.009

Asbtract ( 25 )   PDF (24481KB) ( 32 )  

References | Related Articles | Metrics

To solve the problem of integrated forming of complex tubular parts in the fields of automobiles, aerospace, etc., the concept of composite forming process for block-type metal tubular parts with carbon fiber winding reinforcement is proposed. That is, the complex tubular parts products are first divided into tubular profile modules of different specifications through topological optimization, then the modules are glued and combined, and finally local reinforcement and connection reinforcement of the tubular parts are realized through carbon fiber winding. Among them, the mapping relationship between the carbon fiber winding process parameters and the local performance and connection performance of the tube is the key problem to be solved. Based on this, experimental studies were carried out on carbon fiber wound magnesium alloy tubes. The main conclusions are as follows: at the same angle, with the increase of the number of layers(2~5 layers), the peak load, total energy absorption, and specific energy absorption increased. When winding 5 layers, the specific energy absorption of axial compression increased by 177% and the peak load increased by 38% compared with the bare pipe. Under the same number of layers, small angles(±30°) enhanced the axial compression and three-point bending properties, while large angles(±90°) improved the transverse compression, indentation, and torsional resistance, providing a basis for the precise regulation of the bearing performance of the pipes. Secondly, the “geodesic-non-geodesic” collaborative fiber winding reinforcement was adopted for the connection structure of the pipe components to solve the problems of fiber slippage and stress concentration. It was found that carbon fiber could significantly improve the bearing capacity and energy absorption characteristics of the connection structure. The research results verified the engineering feasibility of the proposed forming process concept.

Collaborative optimization of lightweight and crashworthiness for TRB-CFRP super-hybrid automotive B-pillar

SHI Fengbao, WU Xiongfang, BU Tong’an, ZHANG Weiliang, ZHAO Qianjuan, CHENGZhangjie

2026, 0(6):  88-96.  DOI: 10.19936/j.cnki.2096-8000.20260628.010

Asbtract ( 27 )   PDF (14229KB) ( 33 )  

References | Related Articles | Metrics

In response to the technical bottleneck that lightweight and crashworthiness are difficult to be improved collaboratively for conventional automotive B-pillars, a super-hybrid automotive B-pillar assembly structure composed of an ultra-high-strength steel outer panel with variable cross-sectional thickness and a carbon fiber reinforced polymer(CFRP) inner reinforcing panel was proposed. The outer panel was treated with sandblasting and interface intercalation treatment, and the B-pillar assembly structure was integrally formed by combining it with the CFRP inner panel via the prepreg compression molding process. We carried out a collaborative optimization on the cross-sectional thickness of the outer panel and the ply parameters of the CFRP inner panel via OptiStruct software, and formulated a multi-angle crash test scheme for the B-pillar subsystem to replace the full-vehicle side impact test. Finite element simulations and physical experimental validations were conducted for both static three-point bending and multi-angle crash test conditions. The results show that the new solution achieves a 17.4% weight reduction for the B-pillar assembly structure, with the CFRP inner reinforcing panel contributing a 63.2% weight reduction compared to the original metal inner panel. Meanwhile, the intrusion displacement of the B-pillar subsystem under crashworthiness conditions is reduced by 13.8% to 27.8%, and the occupant survival space in the full-vehicle side impact test is increased 11.1%, representing a significant improvement in crash safety performance. The deviation between finite element simulation results and experimental data is less than 9.9%, which verifies the accuracy and reliability of the proposed method. Thus, the super-hybrid structure provides a feasible technical path for the collaborative optimization of lightweight and crashworthiness for key load-bearing components of automobiles.

Optimization of polyurea insulating materials based on dynamic crosslinking of disulfide bonds

WANG Fan, WANG Yang, JIA Zheng, LU Junjun, LIU Tongbao, QIAN Miaowang, WANG Weihua, ZHANG Jianjun

2026, 0(6):  97-105.  DOI: 10.19936/j.cnki.2096-8000.20260628.011

Asbtract ( 26 )   PDF (9191KB) ( 31 )  

References | Related Articles | Metrics

With the insulation faults caused by bird damage, foreign object short circuits and extreme weather in transmission lines showing an increasing trend year by year, improving the insulation strength of the gap between transmission towers has become an urgent problem to be solved. This paper aims at the problems of insufficient performance of traditional insulating sheaths and difficult insulation protection on the ground potential side. Using bis-(4-hydroxyphenyl) disulfide as a chain extender and by regulating the molecular weight ratio of polypropylene glycol bis(2-aminopropyl ether), polyurea materials with dynamic disulfide bonds are synthesized. The chemical structure, microstructure, hydrophobicity, chemical resistance, thermal properties and breakdown strength of the material were studied byinfrared spectroscopy(FT-IR), contact angle measurement, SEM and differential scanning calorimetry. The results show that an increase in the content of PPG-2000 can significantly improve the hydrophobicity of the material(with a maximum contact angle of 97.1°) and reduce the water absorption rate(as low as 3.32%). In addition, the breakdown strength is 20.03 kV/mm when the molar ratio is 1.5∶0.5. Further gap simulation tests show that a 4.5 mm thick coating can increase the breakdown voltage of the tower gap by 4.8%. This research provides a new type of polyurea material design and experimental basis for insulation strengthening on the ground potential side of transmission lines, which has important engineering application value.

Removable salt-assisted construction of graphene/carbon nanotube networks and their performance in polyetheretherketone composites

SHEN Zhengpeng, MEI Qilin, DING Guomin, WANG Yao, GAO Linqin

2026, 0(6):  106-118.  DOI: 10.19936/j.cnki.2096-8000.20260628.012

Asbtract ( 26 )   PDF (22436KB) ( 34 )  

References | Related Articles | Metrics

The intrinsic high conductivity of graphene(Gr) and the mechanical enhancement effect of carbon nanotubes(CNT) on the matrix provide an effective pathway for developing structural-functional integrated polyetheretherketone(PEEK) composites targeting antistatic, sensing, and electromagnetic absorption applications. By hybridizing these one-dimensional and two-dimensional nanocarbon materials to leverage their synergistic effects, the mechanical properties of the composites are enhanced and the construction of conductive networks is optimized. Utilizing NH₄⁺ bridging, graphene oxide(GO) and acidified carbon nanotubes(aCNT) were uniformly coated onto PEEK powder surfaces via electrostatic adsorption. The coating status and salt removability were investigated through SEM, FTIR, and TG analyses. The graphene-carbon nanotube/PEEK(Gr-CNT/PEEK) composite(the ratio of Gr and CNT is 5∶5), prepared through thermal treatment, chemical reduction, and compression molding, exhibited a low percolation threshold(0.8wt%) and high electrical conductivity(5.64×10^-3 S/cm), surpassing the PEEK matrix by 12 orders of magnitude. At 2wt% filler content, the conductivity reached 7×10^-3 S/cm, while at 0.3wt%, the tensile strength increased to 110 MPa, representing a 10% improvement over pure resin. Furthermore, by adjusting the hybrid carbon filler ratio, the composites demonstrated distinct sensing behaviors during cyclic stretching. When the ratio of Gr and CNT is5∶5, the composite exhibited relatively stable ΔR/R₀ with a high gauge factor(G_F).

Research on the synergistic effect of catalysts and internal release agents in fiber-reinforced polyurethane pultrusion process

FU Luoping, ZHAI Baoli, ZHANG Lin, XU Yingte, JIANG Jun, WANG Endong

2026, 0(6):  119-125.  DOI: 10.19936/j.cnki.2096-8000.20260628.013

Asbtract ( 29 )   PDF (3349KB) ( 57 )  

References | Related Articles | Metrics

Fiber-reinforced pultrusion processes have established a pivotal position in composite manufacturing due to their high efficiency and precision. Polyurethane(PU) pultrusion, characterized by rapid forming speed and minimal process odor, has emerged as an ideal matrix material for pultrusion technologies. In the PU pultrusion process, the regulation of the catalytic system is critical for production efficiency, process window, and product performance. This study systematically investigates the inhibitory effect of internal mold release agents(IMRAs) on the catalytic activity of amine- and metal-based catalysts in fiber-reinforced PU pultrusion systems. The research reveals that both acidic and alkaline IMRAs suppress catalyst activity, significantly prolonging the gel time at room temperature, whereas the inhibitory effect weakens at high temperatures. Through optimized selection of catalyst and IMRA typesand dosages—using TCAT-S054 catalyst at 0.3wt% and G-161A(4.0wt%~4.5wt%) or INT-1948(3.5wt%~4.0wt%) as IMRAs—the developed system was applied to pultrusion of photovoltaic(PV) frame profiles. The process achieved a pultrusion speed of 1.0 m/min, with the profiles exhibiting smooth surfaces and paint adhesion reaching Grade 0, meeting the highest industry standards.

ENGINEERING APPLICATION

Curing deformation prediction and process parameters optimization of stiffened composite panel in autoclave molding

LI Xueqin, ZHAI Quansheng, CHEN Zhigang, YE Hongjun

2026, 0(6):  126-136.  DOI: 10.19936/j.cnki.2096-8000.20260628.014

Asbtract ( 37 )   PDF (15722KB) ( 67 )  

References | Related Articles | Metrics

A finite element method was used to establish a multi-physics curing deformation simulation model for stiffened composite panel formed by autoclave pressing. The temperature and curing degree during the process were introduced as initial conditions into the simulation model. A material constitutive model was defined to enable the calculation of curing deformation. The model was validated using an L-type part, with an error of 1.24% for curing degree and -11.4% for curing deformation. The optimization design of process parameters had been achieved by combination of multi-objective genetic algorithm and a surrogate model for the curing deformation simulation of stiffened composite panel. The ensemble of finite element simulation and optimization algorithms for stiffened composite panel structures can improve curing uniformity and reduce curing deformation, so as to help us to improve molding quality and increase efficiency of process optimization.

Mechanical model and application of adhesive repair for broken holes in aircraft composite skin

LIANG Yun, WANG Heng, YANG Chaojun

2026, 0(6):  137-145.  DOI: 10.19936/j.cnki.2096-8000.20260628.015

Asbtract ( 22 )   PDF (5350KB) ( 50 )  

References | Related Articles | Metrics

In order to quickly design repair plans for aircraft composite material perforation damage, a general mechanical analysis model for composite material lap joints under complex loads was established. The additional bending moment and shear force caused by axial tension in the skin perforation repair model were solved, and the distribution curves of shear stress and peel stress in the joint overlap section were obtained, which are close to the results of finite element analysis. This model provides strong support for the rapid design and joint analysis of maintenance plans. The model results indicate that using the same panel as the original structure for patching or appropriately increasing the overlap length and adhesive layer thickness can achieve better repair strength.

Study on degradation and closed-loop recycling of wind power composite based on alcohol-alkali catalytic system

YAO Yalin, XIAO Hongqing, YAN Chongchong, SHA Qiqi, SU Zhiqiang

2026, 0(6):  146-153.  DOI: 10.19936/j.cnki.2096-8000.20260628.016

Asbtract ( 25 )   PDF (8440KB) ( 35 )  

References | Related Articles | Metrics

Epoxy resin-based composites are widely used in the wind energy industry. Due to the stable three-dimensional network structure formed after the crosslinking of epoxy resin, the recycling and utilization of a large number of discarded wind turbine blade composites have become a challenge. Against this backdrop, this study developed a catalyst system using an alcohol solution of potassium hydroxide, which enables the complete degradation of acid-anhydride-cured epoxy resin under mild reaction conditions of 100 ℃ for 8 hours. This method was applied to the degradation and recycling of pultruded plates. During the reaction, the ester bonds in the polymer were selectively cleaved, with the epoxy resin-based portion transformed into bisphenol A glycidyl ether, and the methyltetrahydrophthalic anhydride curing agent converted into carboxylate salts. Meanwhile, the glass fiber/carbon fiber was completely recovered. The degradation product, bisphenol A glycidyl ether, was used as an active component and reused in the pultruded plate resin formulation, maintaining high strength and modulus. The carboxylate salts were post-treated to convert into high-purity methyltetrahydrophthalic anhydride, which was reused as a curing agent in the pultruded epoxy resin formulation, and the mechanical properties of the pultruded plates reached the same level as commercially available products.

Air-coupled Lamb wave detection method of engine casing/composite bonding

GAO Xiaojin, LIU Tao, LI Zhaotong, LI Chen, LIU Geliang, MEI Hui

2026, 0(6):  154-158.  DOI: 10.19936/j.cnki.2096-8000.20260628.017

Asbtract ( 28 )   PDF (5290KB) ( 35 )  

References | Related Articles | Metrics

Based on the characteristics of the bonding structure of metal shell/ceramic matrix composite material for solid rocket engine nozzle, the applicability of liquid coupled ultrasonic reflection method, ultrasonic penetration method, and ultrasonic phase method for detecting bonding quality was analyzed, and it was found that they are all difficult to detect. A method of air-coupled Lamb waves at one side was proposed, and the proposed testing method was used to test the bonding specimens of 304L stainless steel and C_f/SiC composite materials containing artificial debonding defects. The detection results and analysis indicate that the proposed method does not use liquid coupling agents, but directly uses air as the coupling agent, and the probe was arranged on the outside of the product, which was suitable for the detection of solid rocket motor nozzles after loading; the method of using soundproof panel was proposed to solve the problem of difficult distinction between Lamb waves and straight through waves, successfully achieving the separation of Lamb wave detection signals at the debonding point; all artificial debonding defects were detected in the solid rocket motor nozzle specimens, with a detection sensitivity of 5 mm×2.5 mm. The dimensional errors in the length and width directions of the defects were not greater than 2 mm, and the error in the defect area was not greater than 15%, achieving ultrasonic testing of the bonding quality of the engine casing/composite material.

REVIEW

Research advances in high performance epoxy resin adhesives

ZHAO Yan, MU Xuesong, CHEN Wengang

2026, 0(6):  159-168.  DOI: 10.19936/j.cnki.2096-8000.20260628.018

Asbtract ( 38 )   PDF (994KB) ( 56 )  

References | Related Articles | Metrics

With the development of modern industrial technology, the requirements for material performance are continuously increasing. The aviation manufacturing sector urgently needs to continuously optimize the comprehensive performance of epoxy adhesives under complex working conditions, to overcome the key technologies of bonding and sealing in aircraft honeycomb sandwich structures, thereby promoting the collaborative innovation of lightweight and reliability in China’s aviation industry. This paper reviews the practical applications and research progress of epoxy resin adhesives, emphasizing the influencing factors of the thermal resistance performance of epoxy adhesives and the technical methods to improve their thermal resistance, as well as providing a detailed explanation of the toughening mechanism of epoxy resins.