The application of carbon fiber reinforced composite mold greatly reduces the cure-induced distortion f composite parts, because the mismatch of thermal expansion coefficients between mold–part can be decreased. The self-heating technology of the composite mold is essential to achieving a high-quality and high-efficiency curing process. However, the existing self-heating methods are difficult to avoid introducing a large number of heating elements and cables, which lead to mold structure failure and a shortened life after repeated thermal cycles. In this paper, a multi-zoned selfheating technology of composite mold based on an electrically anisotropic laminate structure is proposed. By inserting an isolation layer into the carbon fiber laminate, an unidirectional conductive laminate structure is formed, and several stripshaped heating areas that can be independently temperature-controlled are achieved by feeding located electrical current. Finally, the multi-zoned temperature control of the mold temperature field without introducing any heating elements and cables is achieved. Compared with the traditional self-heating tool, the in-plane temperature uniformity of this work is improved by 92.1%, and the spring-in of the cured C-shaped part is reduced by 27.0%. The multi-zoned self-heating composite mold has matched thermal expansion coefficients and can achieve precise temperature control of parts, which provides a new solution for the high-quality and efficient curing process.

Continuous fibre reinforced thermoplastic plastics (CoFRTP) exhibit the advantages of fast manufacturing, high fracture toughness and high recyclability, which are promising materials for aerospace and automotive industries. Thermoforming process is one of the most promising way for CoFRTP forming since the advantages of high efficiency and low cost. However, due to the amount of forming parameters involved in this process and the complex coupling of factors such as large nonlinearity deformation and multi phase transformation of materials, defects like wrinkles, fiber cracking and excessive dimensional deformation are prone to be induced, which generate great challenges to the mechanical properties of components and the assembly property. In order to overcome the disadvantages of low efficiency and high cost of traditional trial and error methods and improve the efficiency of thermoforming process design, this paper focuses on the review of thermoforming process and numerical methods. This paper includes four parts: the application and manufacturing of CoFRTP, the analysis and research status of thermoforming process, the simulation method of thermoforming process as well as the conclusion and the outlook of thermoforming technology. This study will provide theoretical guidance for highly efficient and high quality forming of CoFRTP, and promote the corresponding structural design and engineering application as well.

Significant progress has been achieved in the research field of characterization models and methodologies for uniaxial and multiaxial fatigue properties of laminated composite structures. In this paper, the damage curve models, residual stiffness models, residual strength models, fatigue modulus models and S –N curve models for fatigue damage evolution were reviewed, aiming at analyzing and predicting fatigue property of fiber reinforced composite laminates. Furthermore, the fatigue failure criteria and fatigue life predicting models and methodologies were summarized and analyzed. Meanwhile, the deficiency in fatigue research of composite materials was elaborated. The research shows that the theoretical models of fatigue damage evolution and life prediction are mostly macroscopic phenomenological models, and rarely involve micro-damage forms and mechanisms. Although the finite element method for life prediction of multidirectional laminates has wide applicability, it is not enough to simulate the real damage path and course of composite materials. Based on this analysis, the key future research direction of fatigue damage and life of composites was prospected.

Carbon fiber reinforced polymer matrix composites (CFRP) are widely used in various fields because of their excellent properties such as high specific modulus, high specific strength and fatigue resistance. However, due Carbon fiber reinforced polymer matrix composites (CFRP) are widely used in various fields because of their excellent properties such as high specific modulus, high specific strength and fatigue resistance. However, due to its complex use environment, it is easy to cause damage in the process of service and form a safety hazard. For this reason, scholars at home and abroad have studied the mechanical properties of CFRP laminates. The research progress of mechanical properties simulation of CFRP laminates is systematically reviewed from the four perspectives of impact damage, delamination damage, high and low temperature and damp-heat aging and multi-field coupled damage. The research status of CFRP laminate damage mechanism simulation based on advanced numerical analysis methods such as virtual crack closure technology (VCCT), cohesion zone model (CZM) and progressive damage constitutive model (PDM) is described in detail. By comparing different finite element simulation methods, the advantages and existing problems are pointed out, and the future research direction of the mechanical properties simulation of CFRP laminates is prospected. to its complex use environment, it is easy to cause damage in the process of service and form a safety hazard. For this reason, scholars at home and abroad have studied the mechanical properties of CFRP laminates. The research progress of mechanical properties simulation of CFRP laminates is systematically reviewed from the four perspectives of impact damage, delamination damage, high and low temperature and damp-heat aging and multi-field coupled damage. The research status of CFRP laminate damage mechanism simulation based on advanced numerical analysis methods such as virtual crack closure technology (VCCT), cohesion zone model (CZM) and progressive damage constitutive model (PDM) is described in detail. By comparing different finite element simulation methods, the advantages and existing problems are pointed out, and the future research direction of the mechanical properties simulation of CFRP laminates is prospected.

Random fiber network materials are ubiquitous in biological and artificial materials and extensively utilized in filtration and absorption, thermal insulation and shock absorption, chemical catalysis, tissue engineering, flexible electronics and aerospace because of their low density, high porosity, large specific surface area, strong deformation ability, excellent specific performances and controllable structures. However, when compared to traditional homogeneous continuous materials, the intricate microstructure of random fiber networks poses significant challenges in studying their mechanical properties. This article provides an extensive review of the research progress made on random fiber networks from two focal points: microstructure characterization and evaluation of mechanical performance. It summarizes the key accomplishments and unresolved issues, encompassing experimental testing, establishment of constitutive relationships, and numerical simulations pertaining to these materials. Additionally, the contribution emphasizes the emerging trends in the research of mechanical performance for random fiber networks.

The mechanical degradation after thermal-oxidative ageing is crucial to the safety and durability design of 3D woven composites. The high-speed camera and micro-CT were employed to characterize the impact compression deformation evolution and internal damage distributions, respectively. A two-step “matrix shrinkage” method was used to study the impact compression behavior of 3D interlocked woven composites before and after ageing to reveal the degradation mechanism after thermo-oxidative ageing. The interface cracks generated on the surface of aged composites continued to increase and widen with the increase of ageing time. The impact properties of aged composites gradually decreased with increasing ageing time, and the compression modulus decreased by 16.6% after 32 days. The combined effects of thermo-oxidative degradation of resin and interface damage in aged composites hinder the transfer of stress waves from resin to yarn, leading to yarn fracture earlier and more severe damage. Meanwhile, the aged interface damage affects the expansion path of shear cracks causing wider and more severe shear bands, which severely degrades the impact properties of aged composites, but does not change the impact 45° shear damage mode. The results provide a theoretical basis for impact engineering fabrication of composites for long-term service under thermal oxygen environments.

C-shaped part is one of the common parts in aviation composite structures. The cure-induced deformation when manufacturing will seriously affect the assembly of aviation structures. In this paper, a method of reducing curing deformation by applying prestressing is proposed for C-shaped part structure, and a numerical analysis model for predicting curing deformation of C-shaped part structure is established. To verify this model, three kinds of C-shaped parts of different layup sequence is manufactured at varying to prestress levels. The experimental results and numerical results have a good agreement, showing the accuracy and validity of this finite element model. It has been shown by the results that once the proper prestress is loaded, the deformation of these three layup sequence parts could reduced over 90%.

As the main method of forming composite material preform, the sticthing technique has been widely applied in areaspace. There are three different ways of stitching including Tufting, chained stitching and locking-type stitching. Different stitching ways had different effects on the permeability and compressibility of stitched preform. Meanwhile the different stitching parameters such as stitch pitch and stitch spacing also had different effects on the permeability and compressibility of stitched preform. In this article, the effects of three different stitching ways including Tufting, chained stitching and locking-type stitching, as well as different stitch pitch and stitch spacing on the permeability and compressibility of stitched preform were studied and compared by experiments. The test results show that the permeability of stitched preform is greater than that of non stitched fabric, and chained stitching > locking-type stitching > Tufting. The permeability of chained type preform increases significantly with the increase of stitch pitch, the permeability of the Tufting preform decreases with the increase of stitch spacing; The relationship between compressibility of stitched preform is as follows: Tufting > chained stitching > non stitched; The compressibility of chained type preform increases with the increase of stitch density; The compressibility of Tufting preform decreases with the increase of stitch pitch.

Carbon foams always show the poor mechanical properties. For application demand-oriented in the field of aerospace, carbon microspheres/Mg₂B₂O₅w hybrid reinforced carbon foam composites, were prepared by the process of compression molding and carbonization, using modified phenolic resin as carbon source, hollow microspheres as dispersed phase, and magnesium borate whisker (Mg₂B₂O₅w) as reinforcement, respectively, to improve their comprehensive performance. The mechanical properties, electromagnetic shielding effectiveness and oxidation resistance properties of carbon foam composites reinforced by carbon microspheres and different mass fractions of Mg₂B₂O₅w, were investigated by SEM, and universal testing machine, respectively. The results showed that Mg₂B₂O₅w played the role of crack deflection and bending bow, and increased the crack propagation path during compression, leading to Mg₂B₂O₅w and hollow carbon microspheres improving the compressive properties of carbon foam composites synergistically. When the mass fraction of Mg₂B₂O₅w is 2%, the compressive strength of the composites reached 11.8 MPa, 157% higher than that of pure carbon foam. The electromagnetic shielding effectiveness of carbon foam composites in the X-band increased significantly, with the increase of Mg₂B₂O₅w content. Mg₂B₂O₅w dispersed on the surface of the matrix and microsphere phases, that increased the pore structure inside the composite material, prolonged the propagation path of electromagnetic waves, and increased the absorption of electromagnetic waves. When the mass fraction of Mg₂B₂O₅w is 8%, the electromagnetic shielding performance reached 53.8 dB, 68% higher than that of pure carbon foam. Mg₂B₂O₅wpresented excellent antioxidant performance. They dispersed on the surface of the matrix and microsphere phase, preventing the contact of hot oxygen with the matrix and microsphere phase, and thus improving the oxidation resistance. When the mass fraction of Mg₂B₂O₅w is 5%, the mass loss rate of carbon foam composites is 24%, and the high-temperature oxidation resistance is the best, which is 12.1% higher than that of pure carbon foam.

In order to eliminate the adverse effects of low-temperature icing on the surfaces of aerospace vehicles, power transmission cables, wind turbine blades, etc., and to enhance the self-cleaning capability of the absorbing coatings on the surfaces of aerospace vehicles, modified hierarchical SiO₂/PU superhydrophobic coating was produced by compounding nano-silicon dioxide (n-SiO₂) and micron-silicon dioxide (m-SiO₂) fillers modified by silane coupling agent with polyurethane (PU) matrix in a 6∶1 mass ratio. The results show that the better dispersion of m-SiO₂ in the PU matrix improves the stability of the coating and effectively eliminates the cracking of the coating due to the agglomeration of n-SiO₂. The n-SiO2 and m-SiO₂ fillers work together on the surface of the coating to build up a dense hierarchical micro-bulge hydrophobic structure, which can trap more air to increase the air–liquid contact area of water droplets. The water contact angle of the hierarchical modified SiO₂/PU superhydrophobic coating can reach 158.56°±1.08° and has good self-cleaning ability and wear resistance. In addition, the excellent wavetransparent property of the hierarchical modified SiO₂/PU superhydrophobic coating does not adversely affect the performance of the absorbing coating. It is shown that the prepared hierarchical modified SiO₂/PU superhydrophobic coating is an ideal protective coating for wave-absorbing materials.