Browse Topic: Polymers

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Study on Shaking Table Model Test of Seismic Dynamic Response of Loess Multi-Arch Tunnels2026-99-1584To be published on 09/11/2026
Taking the Nieye Multi-Arch Tunnel in Zhuoni County as the engineering background, this study systematically explores the seismic dynamic response characteristics of loess multi-arch tunnels through shaking table model tests. The test results show that: (1) The strain distribution of the surrounding rock is significantly different. Under a peak acceleration of 0.6 g, the maximum strain in the tunnel portal section is concentrated on the right side, which is related to the incident direction of seismic waves and the stress concentration at the bottom of the central wall; the maximum strain in the tunnel body section is located on the left side, affected by the propagation characteristics of seismic waves, burial depth, and unsymmetrical pressure. (2) The acceleration amplification factors in the Z and ZX directions show nonlinear changes. Under bidirectional excitation, the Wenchuan wave-ZX combination exhibits the strongest response. The variation trend of acceleration at the soil-rock interface varies with wave types, and the slope damage undergoes three stages: elastic stage, elastoplastic stage, and plastic damage stage. (3) The ratio ω of tunnel burial depth to central wall thickness is positively correlated with the strains at key positions. For the seismic design of loess multi-arch tunnels, special attention should be paid to sensitive areas such as the bottom of the central wall and the left side of the tunnel body. It is suggested to improve the structural seismic performance by optimizing the lining reinforcement and adapting to regional seismic wave types. The research conclusions provide a reference for the seismic design of such tunnels under complex geological conditions.
Han, Tao, Cao, Xiaoping, Zhang, Shulin, Yang, Zibin
Effect of Space Radiation on the Properties of Methyl Phenyl Vinyl Silicone Rubber (MPVQ) Compound2026-99-1424To be published on 09/11/2026
In this study, the influence of space radiation on the properties of methyl phenyl vinyl silicone rubber (MPVQ) compounds is systematically investigated. The results reveal that with increasing radiation dose, the appearance of MPVQ compounds changes from white to pale yellow and then to grayish-yellow, while their hardness continuously increases. Both the tensile strength and tear strength of the samples exhibit the S-shaped variation curves with radiation dose. At a radiation dose of 1 × 10^6 Gy (Si), the tensile strength, elongation at break, and tear strength decrease by 20%, 89%, and 69%, respectively. When the radiation dose exceeds 1 × 10^6 Gy (Si), both the tensile strength and tear strength rebound moderately. However, further increases in the dose cause both properties to decline again. By contrast, the elongation at break decreases consistently throughout the dose range. Besides, the samples are non-flammable in the presence of open flames. According to these experimental results, the MPVQ products can meet the 15-year service lifetime requirement for the static spacecraft, although their elasticity and load-bearing capacity could be substantially diminished, leading to increased brittleness and susceptibility to fracture under stress. However, some physical or chemical modification of the MPVQ materials is definitely needed for their further application in the dynamic mechanism for the long-life spacecraft that are directly exposed to the space environment. In our opinion, the results shown in this work could provide some necessary guidance for the further development of the related materials in the related field.
Wang, Peng, Chen, Yacan, Li, Jiaxin, Wang, Nan, Zhao, Tianqi, Liu, Hanliang, Huang, Zhipeng, Huo, Xiubing, Sun, Wei
Application of Textile Materials in the Design of Safety Protection Products2026-99-04168/28/2026
The research focuses on textile material utilization for safety protection product design to meet rising public safety needs and expanding dangerous operational environments. The research begins by identifying essential performance criteria for safety textiles because these materials serve as core carriers due to their excellent plasticity and functional capabilities and comfort properties. The research examines leading protective materials through a comparative analysis which shows their individual benefits and weaknesses. The study implements an experimental method to evaluate a new aramid fabric composite against flame-resistant cotton fabric through standardized tests which assess protective capabilities and comfort levels and product longevity. The experimental results show that the composite aramid fabric surpasses flame-retardant cotton in all tested parameters including flame resistance and tear strength and durability while providing better thermal comfort. The study establishes a solid quantitative basis for selecting and enhancing textile materials in safety protection product development which enables the industry to create sustainable high-performance protective solutions with multiple functions.
Huang, Jiaqi, Li, He, Peng, Tianxiao
Preparation of 3D Porous Carbon Foam Materials and Research on Their Microwave Absorption Performance2026-99-04108/28/2026
Carbon materials, as typical dielectric loss media, possess the characteristics of low density, stable chemical properties, wide sources, and diverse existing forms, and have been attracting much attention in the microwave absorption field. Based on carbon materials, the rational design and construction of microscopic morphology and microscopic structure is an effective way to improve their microwave absorption performance. Up to now, unique microstructures such as hollow, core-shell, and porous have been widely used in the design of microwave absorption materials, and their performance improvement has also been reliably confirmed. This paper mainly focuses on the research of the preparation and microwave absorption performance of porous carbon foams (CF-x). Firstly, it achieves the fabrication of porous carbon foams by the one-step pyrolysis using readily available glucose and NH4Cl, avoiding the need for polymer templates or magnetic element incorporation. In addition, this paper focuses on investigating the effect of the dosage of NH4Cl on the pore structure and dielectric properties of CF-x, and it reveals the advantages of the foam structure in terms of enhancing microwave absorption performance.
Wang, Fengyuan, Wei, Qi
Dynamic Response and Energy Absorption of a Novel Arc-Shaped Hourglass Re-Entrant Honeycomb under Impact Loading2026-99-04178/28/2026
This study introduces an arc-shaped hourglass re-entrant auxetic honeycomb (AHRH) and examines its impact-induced dynamic response and energy-absorption behavior via finite-element simulations. The conventional re-entrant honeycomb (RH) is adopted as the baseline, and side-by-side simulations are performed at impact speeds of 10, 20, and 30 m/s. The mechanical response of both lattices is assessed through force-displacement characteristics, absorbed-energy histories, and representative deformation modes. Results indicate that the AHRH significantly reduces the initial peak force, prolongs the plateau stage, and exhibits a distinct dual-plateau feature, thereby achieving the desirable crashworthiness mode of “low initial peak-extended plateau-high densification”. Compared with the RH, the AHRH achieves increases of approximately 42.9%-59.7% in total energy absorption and 42.8%-56.1% in specific energy absorption while maintaining nearly identical mass. The enhanced performance arises from the arc-edge geometry, which alleviates local stress concentrations, promotes progressive buckling, and generates multiple plastic hinges. These mechanisms lead to smoother load transfer, avoidance of excessively high initial impact loads, and more efficient crash energy management. Overall, the proposed AHRH structure demonstrates superior energy absorption capacity and deformation stability compared with the conventional RH, providing new insights and practical references for the lightweight design and optimization of advanced protective and crashworthy structures.
Jiang, Zhide, Chen, Long, Yu, Ping
Composite Materials Handbook Volume 5 - Revision BR-4608/27/2026
The fifth volume of this six-volume compendium publishes technical guidance and properties on ceramic matrix composite material systems. The selected guidance on technical topics related to this class of composites includes material selection, processing, characterization, testing, data reduction, design, analysis, quality control, application, case histories, and lessons learned of typical ceramic matrix composite materials. Volume 5, which covers ceramic matrix composites, supersedes MIL-HDBK-17-5 of June 17, 2002. The Composite Materials Handbook, referred to by industry groups as CMH-17, is an engineering reference tool that contains over 1,000 records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites. CMH-17 provides information and guidance necessary to design and fabricate end items from composite materials. It includes properties of composite materials that meet specific data requirements as well as guidelines for design, analysis, material selection, manufacturing, quality control, and repair. The primary purpose of the handbook is to standardize engineering methodologies related to testing, data reduction, and reporting of property data for current and emerging composite materials. It is used by engineers worldwide in designing and fabricating products made from composite materials.
CMH17, CMH-17
Design of a Biomimetic Spherical-End Tool Based on Gastropod-Shell Surface Microstructures and an Investigation of its Polishing Performance2026-99-10018/7/2026
To improve stress-distribution uniformity and reduce wear during polishing, a biomimetic flexible polishing tool was developed by incorporating microstructured surface features inspired by the gastropod shell. A biomimetic flexible polishing tool was first geometrically modeled, and then the tool–workpiece contact was analyzed in the elastic polishing regime using Preston’s material removal equation to elucidate stress transmission and contact deformation mechanisms. An Abaqus finite-element model of the elastic tool–workpiece contact was subsequently established to compute tool and workpiece stress fields and contact-area fraction during polishing. The biomimetic tools were fabricated by curing silicone rubber mixed with carbon nanotubes. Polishing validation was performed on a small CNC platform using quartz glass under the parameters α=15°, ap=2mm, and w=30r/s. Results indicate that the biomimetic tool incorporating gastropod-shell microstructures increases the machining contact area by up to 48.60% relative to a conventional tool, and after t=30 min of polishing the surface roughness Ra decreased from 1.019μm to 76nm. These outcomes demonstrate that the biomimetic microstructured flexible tool effectively improves contact stress uniformity and enhances surface- processing accuracy for quartz glass.
Song, Jintao, Hui, Jizhuang, Guo, Lei, Xu, Chen, Hei, Zhengqiang, Zhong, Taiyang, Wang, Jiawei, Liu, Jin
The Superman of PolymersTBMG-555478/1/2026
What if there were a fabric that, like Superman, could take a bullet and self-heal? Such a super-dynamic, action-powered polymer might actually help protect real-life flyers in space.
Application of a Novel Noise-Reduction Material to Reduce Squeak Noise in Automotive Instrument Panels2026-01-50657/31/2026
In recent years, driven by increasing consumer demands for vehicle aesthetics and perceived quality, automotive instrument panels (IPs) have extensively adopted materials with poor friction compatibility, such as chrome-plated strips and synthetic leather. Concurrently, the engineering requirement for tighter matching gaps between components has significantly escalated the risk of friction noise. Traditional mitigation strategies—such as material substitution, increasing gap clearances, or applying physical isolation—are often difficult to implement due to design constraints, rendering the IP a critical high-risk zone for abnormal noise. This paper proposes a methodology to mitigate squeak noise between polycarbonate/acrylonitrile butadiene styrene (PC/ABS) and its mating counterparts by modifying the viscoelastic characteristics of the PC/ABS base material through the addition of a specialized polymer. Furthermore, a neural network model was established to objectively determine the noise compatibility of these materials. Evaluations of the material compatibility before and after modification demonstrate that adding a specific proportion of the special polymer to PC/ABS significantly improves its friction compatibility with materials such as polyvinyl chloride (PVC) skin. The efficacy of this solution was confirmed through application and verification in a mass-production vehicle.
Liu, Zubin, Cao, Chunyu, Hou, Hangsheng
Research on a Multilayer Membrane Electrothermal Microdriver Based on MEMS Process2026-99-01657/31/2026
Based on the principle of the bimetallic effect of the electrothermal microdrive, polymer SU-eight glue is used as the functional material, nickel metal is used as the structural material, and copper metal is used as the sacrificial layer to make the electric heating microdrive. We process and manufacture them based on specific MEMS processes such as lithography, mask plating, and magnetron sputtering, and perform basic characterization, observation, and electrical signal analysis on the samples. The results show that the overall electrothermal micro-driver device is complete, the electrode and resistance wire structure is complete, and the I-V signal is normal.
Xue, Yunhao, Tan, Xiaolan, Jiang, Xin
Test and Simulation Analysis of Edgewise Compressive Performance of Marine Composite Sandwich Structures with Delamination Defects2026-99-02007/31/2026
In this paper, PTFE membranes were used to preform delamination defects, and VARI technology was employed to prepare marine composite sandwich structures with such defects. The cohesive zone model was used to emulate the interfacial bonding characteristics, thereby establishing a simulation analysis model to assess the edgewise compressive behavior of marine composite sandwich structures with delamination discontinuities. By combining experimental data with simulation results, the edgewise compressive resistance of marine composite sandwich structures was evaluated. Additionally, various parameters including the size, depth, quantity, and geometry of the delamination defects were studied to investigate their effects on the edgewise compressive performance of the marine laminated structures. The research results indicate that as the number of delamination defects increases, the edgewise compressive strength of the sandwich structure gradually decreases. Particularly, when the diameter of the layering defect is less than 30 millimeters, the influence of the defect on the edgewise compressive strength of the sandwich structure can be negligible. Conversely, when the diameter of the defect exceeds 30 millimeters, the rate of decrease in edgewise compressive strength increases significantly with the increase in the diameter of the defect, thereby greatly exacerbating the adverse effects of the delamination defects and ultimately resulting in a 10.77% reduction in the edgewise compressive strength. Furthermore, it was observed that the delamination defects located at the interface between the two panels and the core material on both sides of the sandwich structure do not affect each other, and to a certain extent, improve the compressive stability of the specimen. The degree of edgewise compressive strength reduction caused by elliptical delamination defects with the same area and long axis length is less than that of corresponding circular delamination defects, indicating that using circular delamination defects in the analysis of composite material structures with delamination defects is safer.
Zhang, Yao, Xu, Mingcai, Bian, Tianya, Zhou, Songqiang, Ji, Bing, Cheng, Jiahuan, Zhuang, Ya, Li, Xiang
Tailored Thermo-Mechanical Behaviour of CNT/Epoxy Nanocomposites via Solvent-Assisted Dispersion2026-99-01897/31/2026
Carbon nanotube (CNT) reinforced epoxy nanocomposites were prepared using a solvent-assisted dispersion method and characterized to evaluate their structural, mechanical, and thermal behaviour. X-ray diffraction (XRD) confirmed the presence of CNTs in the polymer matrix through the characteristic (002) reflection, while scanning electron microscopy (SEM) revealed that CNTs were found to be uniformly embedded within the epoxy matrix, showing limited agglomeration and strong interfacial bonding. Fourier-transform infrared spectroscopy (FTIR) supported these observations by revealing absorption bands associated with C=C stretching, C–O–C ether linkages, and O–H vibrations, indicating chemical interactions between CNTs and the epoxy network. Mechanical testing showed that CNT concentrations of 0.25–0.50 wt.% provided the most effective reinforcement, with notable and measurable improvements in tensile and compressive strength as well as modulus. At higher CNT loadings, however, agglomeration led to reduced tensile performance, despite compressive strength remaining comparatively stable. Thermal conductivity increased steadily with CNT addition, from 0.2143 W/m.K for neat epoxy to 0.2435 W/m.K at 0.75–1.00 wt.%, with the most pronounced improvements observed above 0.25 wt.% due to the formation of more efficient conductive pathways. Overall, these findings suggest that low-to-intermediate CNT loadings achieve a practical and useful balance between strength and thermal conductivity while avoiding the drawbacks of excessive filler content. Effective dispersion of nanotubes is a critical factor that governs the mechanical and thermal behaviour of the composites. These results indicate that CNT/epoxy nanocomposites produced under optimized conditions can serve as lightweight, mechanically reliable, and thermally stable materials, making them attractive candidates for advanced applications in aerospace, automotive, and energy-related sectors where both structural performance and efficient thermal management are required.
Gul, Aysenur, Kamali, Ali Reza
Structural Design and Simulation Study of Carbon Fiber Electronic Enclosures for Vehicles2026-99-01607/31/2026
Carbon Fiber Reinforced Polymer (CFRP), as an advanced lightweight structural material, exhibits significant application potential in the protection of electronic devices under extreme vehicle-mounted conditions due to its excellent specific strength and specific stiffness, superior energy absorption capacity, and unique damping and vibration reduction properties. This study closely integrates the characteristics of the complex and variable service environment in vehicles and adheres to the principle of equivalent stiffness matching to conduct innovative design explorations for electronic enclosures made of CFRP. To comprehensively evaluate the dynamic strength performance of CFRP vehicle-mounted enclosures under vibration and impact conditions, in-depth and detailed analyses were conducted using ANSYS software to simulate the power spectral density curves of random vibrations and the loading of post-peak sawtooth waveforms. The results indicate that the carbon fiber enclosure not only achieves remarkable weight reduction but also fully meets the requirements of environmental adaptability standards for automotive equipment. This achievement provides theoretical support and technical guidance for the engineering application of CFRP in the field of vehicle-mounted electronic devices and holds significant engineering application value for promoting the lightweight development of transportation equipment.
Zhang, Shuhui, Ma, Qihua
The Protective Mechanism of Polyurea/Aramid Fiber Reinforced Steel Pipes against Implosion-Induced Multi-Physical Field Loads2026-99-01357/31/2026
This paper studies the protective performance of polyurea-coated steel pipes and aramid fiber-wound steel pipes under the multi-physical field load of internal explosion by combining experiments with numerical simulation. The experimental results show that applying aramid fiber winding has a limited effect on improving the anti-explosion performance of steel pipes, while polyurea-coated steel pipes exhibit better anti-explosion performance under the coupled load of shock waves and fragments. Simulation analysis reveals the protective mechanism of composite structures in terms of energy absorption and stress distribution, providing a theoretical basis for the optimal design of blast-resistant vessels.
Tian, Xiangpeng, Wang, Tao, Bian, Xiaobing, Huang, Guangyan
A High-Efficiency Drilling Equipment for Manufacturing Aviation Materials2026-99-01627/31/2026
This device belongs to the field of aviation materials technology and discloses a high-efficiency drilling equipment for manufacturing aviation materials, which includes a bottom plate. The top of the bottom plate is provided with a clamping structure and a positioning structure. The clamping structure includes a second moving plate, a third sliding groove, a second bi-directional screw, a fourth screw block, a clamping plate, and a rubber block. This device can hold materials through a clamping structure and effectively and quickly locate and drill holes through a positioning structure. By rotating the first threaded rod, it can drive the first screw block to move the U-shaped column. During the movement of the U-shaped column, it will drive the second threaded rod to move together. By rotating the second threaded rod, it will drive the second screw block to adjust the height of the connecting plate for drilling holes. By rotating the third threaded rod, it will drive the first moving plate to move, which will facilitate the multi-directional movement of the drill bit, improve the efficiency of drilling, avoid multiple position changes, and be beneficial for practical applications and operations.
Li, Zuxian, Li, Ling
Study on Formulation Design of Solvent-Free In-Situ Curing Liquid Rubber for Vacuum Sealing Materials2026-99-02037/31/2026
This study adopts a solvent-free in-situ molding process, using liquid ethylene-propylene-diene monomer (LEPDM) as the base rubber to prepare vacuum sealing materials. The effects of the blending ratio of EPDM/LEPDM on mechanical properties, processing characteristics, physical-mechanical properties, compression characteristics, and vacuum condensable volatiles were investigated. The influence of lamellar intercalated structural fillers on gas permeability was also examined. The results indicate that the addition of LEPDM significantly reduces the Mooney viscosity, improves filler dispersion, and achieves good processability. When the LEPDM blending amount exceeds 20 phr, significant changes occur in mechanical properties, compression modulus, and compression set, which are related to phase transformation. Vacuum pretreatment and vacuum condensable volatile test results show that the traditional plasticizer DOP exhibits high total mass loss (TML) and collected volatile condensable materials (CVCM). However, when LEPDM is partially used to replace EPDM at a blending ratio of 20 phr, TML ≤ 1% and CVCM ≤ 0.1% can be achieved. With the increase in organically modified montmorillonite (OMMT) content, the gas permeability coefficient first decreases and then increases. When the OMMT content is 15 phr, the material exhibits good gas barrier properties
Han, Xiao, Shi, Lei, Chen, Zongwen, Zhang, Zhaoyang, Cheng, Wei
Screen-Printed Flexible Sensor for Conveyor Belt Fault Monitoring2026-99-01957/31/2026
Conveyor belt fault detection is critical for ensuring the safety and efficiency of industrial material transportation. In this study, a screen-printed flexible strain sensor based on a thermoplastic polyurethane (TPU) substrate and graphene conductive ink was fabricated. The sensor exhibited excellent flexibility, mechanical robustness, and stable electromechanical performance. Comprehensive evaluations were conducted, including microstructural analysis, strain sensitivity, hysteresis, dynamic response, and long-term cycling stability. The results demonstrated that a two-layer graphene configuration achieved an optimal balance between sensitivity and structural stability, showing high gauge factor, fast response, and reliable cyclic performance. Furthermore, the sensor was applied to conveyor belt fault monitoring. Experiments validated its ability to detect both halting faults and foreign object intrusions, with distinctive resistance signal features enabling not only fault occurrence detection but also identification of fault location, type, and severity. These findings highlight the potential of the proposed flexible sensor system as a promising solution for intelligent conveyor belt monitoring in harsh industrial environments.
Zhang, Bo, Ai, Shigeng, Zhang, Xiaobo, Sun, Wanting, Li, Pengfei
A Simple Method for Synthesizing Wear-Resistant Superhydrophobic Anti-Icing Coating2026-99-01297/31/2026
This research demonstrates a facile method for fabricating an anti-icing coating through spray deposition on a metallic substrate. A dual-layer structure was designed to enhance icephobic properties: a primer layer incorporating fluorocarbon resin, butyl acetate, and rod-shaped micrometer-sized metal oxides to establish a secondary roughness morphology, followed by a topcoat composed of butyl acetate and nano-scaled superhydrophobic particles. Evaluation of the coating performance revealed a maximum water contact angle of 171.9°, indicating exceptional hydrophobicity. Furthermore, the coating exhibited notable abrasion resistance and anti-icing capabilities against overlaying ice.
Li, Dongyang, Xu, Zelong, Wu, Jiang, Tong, Wei, Wang, Weiqing, Cong, Rimei, Qian, Jiawei, Qu, Shaohui
Study on the Properties of Waterborne Polyurethane Laminating Adhesives2026-99-02117/31/2026
This paper designs and synthesizes a series of high-performance waterborne polyurethane (WPU) laminating adhesives using polyester, polyether polyols and isophorone diisocyanate as the main raw materials. It focuses on exploring the effects of polyol types and R value (the ratio of polyol to isocyanate) on the properties of the adhesives, including emulsion viscosity, solid content, water absorption rate of the adhesive film, mechanical properties, and bonding performance on different substrates. The results show that WPU2 with polycarbonate diol (PCDL) as the polyol has the best water resistance and the highest tensile strength; WPU1 with polytetrahydrofuran (PTMG) as the polyol has the optimal elongation at break and exhibits outstanding bonding performance on the polar substrate PET; the regulation of R value can optimize the bonding performance of the adhesive on the non-polar substrate BOPP. This type of WPU laminating adhesive features low VOC emissions, no benzene-based solvents, excellent flexibility, and good resistance to high and low temperatures. It not only meets the environmental protection and safety requirements in packaging fields such as food and medicine, but also shows potential application value in high-end fields like aerospace interior compounding and lightweight transportation structure bonding. Its performance is highly compatible with the strict requirements for materials in the modern aerospace and transportation industries. The adjustable strong adhesiveness, compliance with strict emission standards, and adaptability to various substrates make it an ideal choice for a new generation of composite manufacturing, especially suitable for industrial fields pursuing reliability, sustainability and high performance.
Wang, Chengming, Yu, Jiacheng, Wang, Huixia, Huang, Yiqiang, Ren, Xiue
Development and Technical Verification of A Lunar Dust Environment Simulation Mechanism2026-99-01757/31/2026
Lunar dust consists of extremely fine particles and exhibits electrostatic charging properties and electrostatic adhesion. These characteristics cause lunar dust to be highly susceptible to mobilization during lander touchdowns, rover traversals, and human activities, forming widely distributed dust clouds. Lunar dust contamination not only abrades spacecraft and equipment to impair their performance but also poses a threat to astronauts’ safety. To verify the impact of the lunar dust environment on exploration equipment components, a simulation mechanism adaptable to the thermal vacuum test environment was designed. This mechanism is integrated into the lunar environment simulation system and uses a vacuum stepper motor to drive a ratchet mechanism, enabling precise vibrational injection of simulated lunar dust. It mainly consists of a pretreatment mechanism, a particle sedimentation mechanism, a shielding mechanism, and an ultraviolet (UV) irradiation system. Considering the vacuum operating environment, alternating high and low temperature conditions, as well as the strict requirements for the mechanism’s compact size and high reliability, this paper analyzes in detail a series of problems encountered during the development of the mechanism and their corresponding solutions. Stainless steel and polytetrafluoroethylene (PTFE) were selected as the main materials for the mechanism. Meanwhile, active temperature control measures were adopted to actively regulate the temperature of components such as the motor. Ultimately, the mechanism can withstand alternating high and low temperatures ranging from -150°C to 150°C and a vacuum environment of 5 × 10^–6 Pa. Under this environment, the mechanism can achieve vibration frequency adjustment within the range of 1-5 Hz, and realize the sedimentation of simulated lunar dust particles with a particle size of less than 200 μm over an area of 150 mm × 150 mm. After sedimentation, the simulated lunar dust particles can be charged through the photoelectric effect.
Xu, Menglong, Lv, Shizeng, Li, Guohua, Gong, Jie
Study on Particle Dispersion Mechanism of Ribbon-Type Composite Impeller Based on CFD-DEM2026-99-08187/30/2026
For the solid-liquid mixing of hydroxy-terminated polybutadiene, which is a high-viscosity fluid with a viscosity of 3.5 Pa · s, and micron-sized silicon dioxide particles, this study employs the CFD-DEM numerical simulation method to analyze the solid-liquid mixing process of the ribbon-type composite impeller (RTC impeller). The stirring performance of the RTC impeller is investigated from perspectives including fluid flow field distribution and particle dispersion mechanism. The research results show that the main circulating flow generated by the RTC impeller generally exhibits a roughly symmetric distribution characteristic, and the flow pattern of the main circulating flow on both sides of the central structure is relatively balanced; however, there is a certain difference in the flow trend of the secondary circulating flow pattern on both sides of the central structure. The main circulating flow provides basic flow power for the secondary circulating flow, while the secondary circulating flow adjusts the local energy distribution through vortex motion. These two flows act synergistically to achieve an efficient solid-liquid mixing process.
Li, Ruizheng, Zhang, Yan, Sun, Zhenxing, Wu, Qiong
Surface Modification of SiCw Optimises Impact Resistance of Dual-Polymer Composites2026-99-08627/30/2026
Addressing the performance degradation bottleneck of conventional impact-resistant materials under complex operating conditions, and the limitation of existing research focusing primarily on enhancing single properties while neglecting material equilibrium, this study employs silicon carbide whiskers (SiCw) as the reinforcing phase. Through surface modification techniques, SiCw/celluloid and SiCw/polyimide dual-polymer composite systems were constructed and systematically investigated. Surface modification of SiCw was achieved using titanate and silane coupling agents. Through mechanical testing and X-ray photoelectron spectroscopy (XPS) characterisation, the effects of SiCw loading and modification treatments on composite mechanical properties and interfacial bonding were analysed. Results indicate that SiCw introduction significantly enhances the tensile, flexural, and impact strength of the polymer matrix, with optimal addition ratios identified: 6% for the celluloid system and 1.0% for the polyimide system. Surface modification further optimises toughening effects by reducing surface oxide layers and impurities on SiCw particles while strengthening interfacial bonding. This study provides practical guidance for the system design of high-performance impact-resistant composites. The resulting materials hold broad application prospects in sectors demanding high structural impact resistance, such as aerospace and transportation.
Xue, Kaiming, Hu, Haobang
Influence of Modified Fly Ash Content on the Properties of Resin-Based Friction Materials2026-99-16577/24/2026
In this study, five resin-based brake pad samples with modified fly ash contents of 0%, 4%, 8%, 12%, and 16% were prepared to investigate the influence of fly ash content on the comprehensive performance of the friction materials. The tribological properties of all samples were evaluated under temperature conditions ranging from 100 °C to 350 °C, and their overall performance was assessed using five evaluation indices. Based on the AHP-MOORA algorithm, sample F12 exhibited the highest comprehensive weighted score of 0.11, followed by samples F0 and F8 with scores of 0.10 and 0.09, respectively, indicating a slight decline. In contrast, the comprehensive weighted scores of F4 and F16 were relatively low, at 0.05 and −0.01, respectively. Among the five composites, F12 demonstrated the best overall performance, with F0 and F8 ranking next, while F4 and F16 performed poorly. These results suggest that, within a certain range, increasing the fly ash content can enhance the comprehensive properties of the material. However, excessive addition of fly ash may lead to the detachment of harder particles during wear, thereby increasing wear thickness and wear rate.
Li, Xiaobiao, He, Kang, Zhao, Zhuanzhe, Wu, Bo, Sun, Fei
Experimental Study on The Parameters of the Viscoelastic-Plastic Constitutive Model of a Certain Solid Propellant2026-99-16047/24/2026
The mechanical behavior of a certain solid propellant is not only obviously related to time, temperature, and load loading history, but also is a viscoelastic plastic material under certain conditions. Based on the principle of creep deformation superposition, the strain of the solid propellant material is decomposed into a viscoelastic part and a viscoplastic part, and the nonlinearity of the viscoelastic-plastic constitutive model is manifested by the introduction of nonlinear coefficients. According to the characteristics of the viscoelastic-plastic model of the solid propellant material, the relevant tests were designed. The viscoplastic parameters were determined by using the creep recovery test data of multiple cycles until the failure of the propellant material sample. The viscoelastic parameters of the solid propellant material were obtained by using the data from recovery tests performed under different stress conditions.
Zhang, Jianbin, Sui, Jiuling, Yao, Baotai, Cheng, Dong, Li, Yiming
Towards Realistic Stick-Slip Testing: Efficiently Mapping Material Behavior across a wide Range of Loading Conditions2026-01-07136/20/2026
To minimize noise caused by interior components rubbing against each other, automotive materials are usually tested in advance with the established stick-slip method according to VDA standard 230-206. This procedure is widely used for soft materials, upholstery and plastics. However, it is limited to constant climatic and selected loading conditions. Contrary, in real application, changing climates and dynamic excitations can nevertheless trigger noise issues even in materials rated as suitable in the prior tests. To address this gap, a new test method has been developed that evaluates the stick-slip behavior of material combinations for a wide range of loading and climatic conditions. Conducted in a climate chamber with a standard stick-slip test bench, the procedure applies sinusoidal excitations, dynamic climatic shifts and advanced data analysis. In addition to the usual results the new method also evaluates realistic scenarios such as starting a vehicle in different seasons or sudden jolting movements with high excitation speeds. The result is a detailed map of stick-slip behavior as a function of excitation speed and climate. While requiring a similar level of effort as the traditional test, this approach delivers far greater insight. It enables a more reliable optimization of materials and facilitates targeted material selection for specific applications. In this manner, it can not only contribute to improve product quality but also to achieve quiet interiors and customer satisfaction.
Fritz, Susanne, Strangfeld, Martin
Effect of Backing PU Foam Material Properties on Acoustic Insulation Pad Insertion Loss2026-01-06786/20/2026
The effect of backing polyurethane (PU) foam material properties on the insertion loss of acoustic insulation pads was investigated. First, the material properties affecting the resonant frequency, which mainly determines the insertion loss, were theoretically identified, and practical methods for calculating both the resonant frequency and the insertion loss of the insulation pad were developed. These methods were then applied to evaluate how changes in material properties influence the resonant frequency and insertion loss of the insulation pad. It was found that Young’s modulus, Poisson’s ratio, and thermal characteristic length are the primary material properties that affect these outcomes. The optimal levels of these properties, which are beneficial for interior noise reduction, are derived and presented in this study.
Chae, Ki-Sang, Lee, Moonseok, Kim, Hyunwoo
Bridging Simulation and Reality: Incorporating Seal Contact Detachment Into Stick–Slip Prediction2026-01-07146/20/2026
Noise phenomena in automobiles caused by the stick-slip effect are increasingly among the most frequent reasons for customer complaints and therefore represent a critical vehicle quality attribute. To proactively address such issues, stick-slip testing of contacting material pairs is commonly applied during development. However, the predictive capability of current stick-slip test methods remains limited, particularly when highly flexible materials and realistic, stochastic excitation conditions are involved. The flexibility of sealing systems often allows the actual relative motion at the contact interface to be accommodated through adhesion and elastic deformation, thereby delaying or even preventing sliding. To date, this effect has not been represented by any characteristic parameter in conventional stick-slip testing. Instead, existing evaluations focus exclusively on the analysis of occurring stick-slip oscillations. For the initiation of stick-slip phenomena, however, not only the mean displacement between two stick-slip oscillations during the sliding phase is relevant, but also the relative displacement required to initiate the first slip event of the sealing contact. With the algorithm developed in this work, which reproducibly determines the distance to first slip based on changes in the friction force slope, this methodological gap is now closed. The displacement to first slip depends on numerous influencing factors, including profile geometry, normal load, sliding velocity, excitation profile, and environmental conditions, and was previously inaccessible by both experimental and numerical approaches. In particular, the onset of slip in sealing contacts can now be determined under stochastic excitation of the friction pairing, thereby closely reflecting real operating conditions. As a result, the prevention of noise phenomena can be significantly strengthened at an early stage of vehicle development.
Strangfeld, Martin, Fritz, Susanne, Weber, Jens, Rosell, Anneli
Dynamic Characterisation and Modelling of Electrical Cables under Representative Load Conditions2026-01-06766/20/2026
Electric high voltage (HV) cables are commonly used in automotive applications and very prominently in electrified vehicles. These cables are potential flanking transmission paths for structure-borne sound in a broad frequency range and must therefore be included in the NVH design process. Electrical high voltage cables exhibit non-linear mechanical characteristics, when exposed to significant bending the internal geometry of the cable will change and a curvature dependent bending stiffness will result. The electrical cables envisaged in the current publication feature a helically wound stranded aluminium wire core. This conductive core is covered by, in sequence, a silicone rubber insulation, a braided aluminium wire shield with aluminium foil to minimize electromagnetic interference and a silicone rubber outer sheath. An extensive measurement campaign was carried out to dynamically characterize cable specimen of different lengths and cross sections in terms of multi-degree of freedom transfer stiffnesses from 20 to 2000 Hz. In order to investigate possible temperature dependences this dynamic characterisation was carried out for temperatures ranging from -30 until +60 °C. Moreover, additional measurements on bent cable specimen allowed to assess the dependence of the bending stiffness on the cable curvature. It is shown that suitable results can be obtained by modelling the conductive core using an isotropic multi-layer continuum model and by using corrected material characteristics to account for curvature effects. Temperature effects are shown to be negligible within the tested range.
Nijman, Eugene, Buchegger, Blasius, Böhler, Elmar, Zeller, Bernhard, Rejlek, Jan, Faksa, Lukáš, Lukavsky, David
Improvement of rCF Behaviour through the Introduction of NF2026-37-00396/9/2026
This study investigates the structural improvement of recycled carbon fibre composites through hybridisation with continuous flax fibres to address sustainability concerns and performance limitations. Recycled carbon fibres, while environmentally beneficial, suffer from short, randomized orientations and lower mechanical properties limiting their application beyond decorative uses. This research explores whether incorporating unidirectional flax fibres can enhance rCF behaviour for structural applications. Six hybrid composite layup variants and two plain composites were manufactured using cold compression moulding with Ampro Bio Resin. Each hybrid configuration comprised eight layers, divided into four layers of recycled carbon and four layers of flax fibres oriented at 0°. Complete mechanical characterization was performed following ISO standards for tensile (ISO 527), flexural (ISO 178), and impact (ISO 179) testing. Results demonstrated significant performance improvements in hybrid composites. Among hybrids, layup 2 achieved 212.5 MPa tensile strength whilst layup 3 managed to achieve 20.5 GPa in stiffness. Flexural testing revealed layup 6 achieved the highest flexural modulus of 19.6 GPa among hybrids. Impact resistance improved dramatically with layup 3 demonstrating 186% improvement in energy absorption over recycled carbon fibre. The study confirms that hybridisation creates a positive effect, producing more predictable and durable materials. The complementary behaviour between brittle and ductile materials enhances damage tolerance and structural integrity, establishing a foundation for sustainable engineering materials suitable for automotive applications without compromising reliability.
Hnatyk, Dawid, Chrysanthou, Andreas, De Vuyst, Tom, Ismail, Sikiru
Evaluation of Thermal Behaviour of Ramie Fiber/Delrin Composites for Aircraft Cabin Components2026-26-07546/1/2026
This research investigates the fabrication and evaluation of Delrin (polyoxymethylene, POM) composites reinforcing 5-20 wt.% chopped ramie fiber (RF). The polymer composites were fabricated via the injection moulding technique. Glass transition temperature (Tg), thermal conductivity, Vicat softening temperature (VST), heat deflection temperature (HDT), melt flow index (MFI), and coefficient of linear thermal expansion (CLTE) were the various thermal characteristics of the sustainable composites that were systematically evaluated as per the ASTM standards. The addition of RF drastically altered the Delrin matrix's performance. Among the formulations, the composite with 15 wt.% RF had the best combination of properties: higher VST and HDT values, which provide greater dimensional stability at high temperatures; lower CLTE, resulting in less thermal expansion; comparatively better thermal conductivity; and improved heat dissipation. Eventually, there was a moderate drop in the MFI, indicating more rigid polymer chains that restrict the flowability of the composite, thereby increasing its heat-withstanding capabilities. DSC analysis revealed a slight upward shift in Tg and increased crystallinity, suggesting restricted polymer chain mobility and enhanced load transfer at 20 wt.% RF loadings, agglomeration effects, and weaker interfacial bonding with the matrix led to deterioration in properties. Aircraft cabin components like interior panels, ducting supports, and lightweight non-structural fittings requires dimensional stability, thermal resistance, and mechanical reliability under fluctuating flight conditions.
S, Thirumalvalavan, Senthilkumar, N., Selvarasu, S
Evaluating Volume and Hardness change in Fluorocarbon and Ethylene Propylene Rubber Elastomers: Effects of Fluid Aging2026-26-07586/1/2026
Abstract: This research paper investigates the performance of FKM (Fluorocarbon) seal material when exposed to a 50:50 ethylene glycol-water mixture. The study aims to determine the volume change percentage and Hardness change of FKM elastomers under standardized testing conditions. The experimental approach follows ASTM D471 and ASTM 2240 guidelines, focusing on weight and hardness measurements of the test samples to establish a success criterion. The results provide critical insights into the chemical compatibility and durability of FKM elastomers in Aerospace and industrial applications where ethylene glycol-water mixtures are commonly used. The findings contribute to enhanced material selection and design considerations for sealing applications subjected to glycol-based fluids. Samples of FKM material were immersed in the fluid at controlled temperatures and durations, simulating real-world operational conditions. The primary metric of interest, volume change percentage and Hardness change, were assessed through precision measurement techniques. Weight changes before and after immersion were also recorded to correlate material absorption characteristics with the success criteria. Success thresholds were established based on industry requirements for seal integrity and operational reliability. Preliminary results indicate that FKM exhibits minimal volume expansion and hardness change under specified conditions, aligning with the acceptance criteria. These findings support the suitability of FKM seals for long-term use in coolant systems, with implications for material selection and design in demanding applications. This research contributes to the development of durable sealing solutions, ensuring reliability and safety in systems utilizing ethylene glycol-based coolants. Keywords: FKM, Volume Expansion, ASTM D471
Yarolkar, Makrand, Patil, Sandip, Singh, Tanul
Development of Graphene Filled Polypropylene Nanocomposite for Aerospace Application2026-26-07396/1/2026
Polypropylene, a commodity plastic, is the semi-crystalline thermoplastics widely used in high volume for general purpose application. Polypropylene is the macro molecules of soft and weak backbone, which by reinforcement of fillers in different forms such as fiber, spheroids, nanotubes, flakes, etc., can influence its mechanical, thermal, electrical, creep resistance, and flame resistance properties for use in aerospace applications. Currently, polycarbonate and nylon plastics are used in aerospace applications, however, they are expensive compared with polypropylene. In this thesis, efforts are put to study the effect of reinforcement fillers in the properties of polypropylene composite, primarily the mechanical and flammability properties. The matrix element, polypropylene co polymer and reprocessed polypropylene blended in equal ratio, are coupled with the dispersing phases such as graphene, mica, fumed silica, and polydimethylsiloxane polymer. Effect of graphene as reinforcing filler at different weight % to polypropylene composite’s properties are studied and compared with that of the neat polypropylene. Effect of coupling agent, Aminopropyltriethoxysilane (APTES), on mineral fillers and Polydimethylsiloxane polymer (PDMS) used for crosslinking with the polypropylene matrix is also studied and compared using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) techniques.
Govindaraju, Parthasarathy
Drilling Studies on Sustainable Lightweight Hybrid Polymer Matrix High-Performance Nanocomposites2026-26-07326/1/2026
Worldwide, engineers are exploring the possibility of using polymer composites in their quest for lightweight materials. In this study, injection moulding was used to develop a biodegradable polymer PLA composite containing 20 wt.% vetiver fibers (VFs) and 2 wt.% nano-silica (nSiO2) obtained from pearl millet, which is sustainable. Materials need machining as secondary operation that required joining. Desirability analysis was used to examine and optimize machining (drilling) studies that were designed with Taguchi's design (L9 orthogonal array). Surface roughness (SR) and delamination factor (Fd) were taken as outputs, while spindle speed (SS), feed rate (FR), and drill diameter (DD) were the inputs. Drilling studies were performed on a single vertical machining center (VMC). ANOVA identifies that the FR had the most decisive influence on SR (F=559.24, p=0.001785), followed by DD and SS. FR is the dominant contributor to Fd (F=379, p=0.00263), followed by SS and DD. At low SS and high FR, excessive thrust and heat cause fiber-matrix tearing and poor hole finish. Higher SS softens the PLA matrix, improving surface quality. Fd decreases with increasing SS, whereas it rises with extreme FR and DD due to elevated thrust and matrix cracking. The optimized parameters SS of 3000 rpm, FR of 15 mm/min, and DD of 6 mm achieved a maximum combined desirability of 1. A non-traditional meta-heuristic technique, the frog leaping algorithm (FLA), is adopted to optimize the inputs based on the developed regression model. FLA also provides the identical optimal condition as the desirability function, predicting the outputs SR=2.2195 μm and Fd=1.0383, which are very close.
Senthilkumar, N.
Investigating the Electrochemical Corrosion Behaviour of Bamboo Fiber-Marine Waste Reinforced Polymer Matrix Hybrid Composites for Light Weight Applications2026-26-07336/1/2026
This study investigates the corrosion behaviour of bamboo-crab shell fortified polymer matrix hybrid composites. Three unique hybrid composites were created utilizing the hand layup approach, with epoxy as the matrix material, 15 wt.% bamboo fibers (BFs), and varying quantities (3, 6, and 9 wt. %) of marine resource crab shell (CS). Electrochemical corrosion tests were utilized to evaluate the hybrid sustainable composite's corrosion behaviour. The testing results reveal that epoxy-15 wt.%BF-6 wt.%CS (P2) composite has better corrosion resistance than epoxy-15 wt.%BF-3 wt.%CS (P1) and epoxy-15 wt.%BF-9 wt.%CS (P3). A potentiodynamic polarization test revealed an icorr value roughly five times lower than P1 and three times lower than P3 composites. Furthermore, the Nyquist plot obtained from the EIS study revealed that the P2 composite has a larger capacity loop than the P1 and P3 composites. It also indicates that the P2 composite is more resistant to corrosion than the other two. The more homogenous distribution of CS in P2 composites contributes to their superior corrosion resistance.
Senthilkumar, N., Srinivasan, D, G, Perumal, Balakrishnan, Deepanraj
Surface Protection Strategies for Dome Shaped Structures against Cavitation Erosion2026-26-07446/1/2026
Submarine-launched missiles with domed nose cones are highly vulnerable to cavitation erosion as they travel at high speed through an underwater launch tube and then into the air from the sea surface. The collapse of vapour cavities crystallizes intense damage on the vehicle surfaces so that the vehicle structure and aerodynamic performance are threatened. In this work, we show the full 3D numerical and analytical analysis of surface protection concepts for the reduction of cavitation damage on such an axisymmetric dome-shaped body. A computational methodology was developed by importing a complex computer-aided design (CAD) model of a dome and the connecting tubular structure into a high-fidelity simulation environment. The geometry was simplified by omitting non-essential details to facilitate the generation of quality mesh for CFD analysis. Simulations have been carried out to analyze the flow field and pressure distribution under two critical stages, at two angles of attack of 0° and 12° and different launch depths. This investigation focuses on a passive mitigation technique that bonds an optimised rubber padding to the dome's exterior surface. The impact forces from collapsing cavitation bubbles are thought to be absorbed and dissipated by the rubber due to its viscoelastic nature, leading to a reduction of the impulsive stress on the substrate. The results show that the controlled introduction of such a compliant material dramatically changes the surface response to cavitation implosions. The suggested rubber padding is demonstrated to be an efficient and practicable means of protecting the surface; thus, the risk of cavitation erosion is diminished considerably, and the service life and reliability of the underwater projectile vehicle can be improved.
Velayudhan, Gautham, P S, Premkumar, S, Suhail Ahmed, P, Krishnakumar, Vasantharaj, C
Electrical Harnessing in Satellite Launch Vehicles of ISRO – Methods for Sustainable, Safe and Reliable Systems2026-26-07796/1/2026
The electrical harness system of satellite launch vehicles functions as the backbone of spacecraft avionics; inter connecting subsystems through complex networks of wires and connectors. An electrical harness is a group of wires bunched together and terminated in connectors. The common insulations used for launch vehicle applications include PTFE, Polyimide, ETFE and TKT. The connectors used are of aerospace grade and connectors tailored for space applications. With over 5000 connectors and 200 km of cables constituting nearly 20% of vehicle mass, the design, fabrication, and sustainability of these systems are critical. The insulations of connectors inserts or the wires are critical for the durability of harness elements. Nevertheless, these insulations are non-expendable and pose disposal challenges and some releases toxic gases when burned or due to vacuum outgassing phenomenon. Also, the cadmium plating which is often used for the environmental resistance of connector shells presents additional risks to the working humans due to its carcinogenic nature and shows tendency to bloom out during storage. This paper presents the methodologies and innovations implemented to develop safe, reliable, and environmentally sustainable harness systems for current and future launch vehicles. Key advancements include the adoption of lean manufacturing practices for waste reduction, the replacement of hazardous cadmium-plated connector shells with stainless-steel alternatives, and the induction of TKT-insulated wires to prevent arc tracking and ensure human-rating compatibility. Additionally, lightweight composite connectors and micro-miniature interconnects are being qualified to support mass optimization in reusable launch vehicles. Through these strategic measures, the study demonstrates how the integration of sustainable materials, safety-oriented design, and process optimization can enhance the performance, safety, and environmental footprint of launch vehicle electrical harness systems.
K S, Nithish, TR, Binny, D S, Praveen Kumar
Assessment of Injection Gate Location Effects on Mechanical Performance of Short Fiber Reinforced Plastic Components Using Digimat2026-26-07466/1/2026
The mechanical performance of short fiber-reinforced plastic (SFRP) components is highly sensitive to fiber orientation, which is significantly influenced by the injection gate location during the molding process. Traditionally, gate placement decisions are driven by warpage minimization strategies, often overlooking mechanical performance under diverse load cases. This research introduces an automated workflow within Digimat-MS that integrates injection gate optimization into the early design phase, leveraging Integrated Computational Materials Engineering (ICME) principles. The proposed methodology enables engineers to upload either Marc, Abaqus or Ansys input decks, select a component of interest, assign material cards, and define gate scenarios. A Design of Experiments (DOE) is then executed locally or remotely, allowing Digimat to evaluate multiple gate configurations. The system aggregates results and identifies optimal gate locations based on the initiation of failure under quasi-static loading conditions, thereby reducing reliance on trial-and-error and expert intuition. This approach not only streamlines the simulation process but also ensures that gate placement decisions are informed by comprehensive mechanical assessments across multiple load cases. The integration of Digimat’s ICME capabilities enhances simulation accuracy, leading to improved reliability and performance of SFRP components.
Kauthale, Tanmay, Madhavan, Vinay, Soni, Ganesh
Retrofit Vibration Mitigation of Launch Vehicle Structures Using Thin Viscoelastic Coatings: Acoustic and Modal Study2026-26-07366/1/2026
Acoustic-induced vibrations pose a significant risk to launch vehicle hardware and payload reliability during critical phases such as lift-off and transonic phase. Reducing such vibrations is especially challenging when the hardware has already been fabricated, limiting the possibility of structural redesign. This study demonstrates a practical post-fabrication solution using a thin viscoelastic polymer coating applied externally to fully assembled hardware. Comprehensive evaluations were conducted using both acoustic testing and Experimental Modal Analysis (EMA) before and after coating application. During acoustic test, a substantial decrease in structure response from 150Hz to 2000Hz, with a reduction of approximately 50% in the grms values was observed for the coated structure demonstrating significant vibration mitigation over a wide frequency range. In contrast, EMA measurements using impact excitation revealed that the response transfer functions did not show a significant reduction within the band considered and modal properties remained largely unchanged upto 200 Hz, indicating that the coating did not significantly alter the structural properties. The apparent enigma calls for a detailed study. A brief overview on the results and the plausible reasons are detailed in the paper. Out of the probable causes, the observed vibration reduction can be primarily attributed to the operational damping and mass addition effects of the PC10 coating. These findings highlight an effective and practical approach for mitigating acoustic-induced vibrations in aerospace structures, with direct application to launch vehicle stages and other aerospace hardware where post-fabrication solutions are critically needed.
Avirah, Nohin K, Panda, Ajay Kumar, Shaikh, Altafhusen
Improvement of Mechanical Properties of Synthetic Fiber Reinforced Composites through Addition of Graphene Oxide2026-26-07536/1/2026
Unmanned Aerial Vehicles (UAVs) demand structural materials that are lightweight, strong, impact-resistant, and durable in diverse environments. The synthetic fiber reinforced polymer composites have varying mechanical performance depending on the fiber matrix interfacial properties. This research analyzes the influence of Graphene Oxide (GO) nano fillers on mechanical properties of composites. Firstly, the epoxy resin was modified by incorporating different weight percentage of Graphene Oxide. This resin was used to make an composite laminate using different materials (Carbon, Glass and combination of these fibers). Then the composites were put through the tensile, compression, flexural tests. The synthetic fiber reinforced polymer composites have a significant improvement in mechanical properties due to the addition of Graphene Oxide.
Manoharan, Dinesh, Langford, Peter, M.K., Padmanabhan, R, Prithviraj, Rajkumar, Subbiah, Karthikeyan, Ravikumar, Veeramuthu, Balasubramaniyan, Gunaseelan, John, T, Thangaraj
Mitigating Cracking in COP Optics through Annealing and Step-Torquing2026-26-07646/1/2026
Polymeric optical materials such as Cyclo Olefin Polymer (COP) are adopted in aerospace lighting systems due to their excellent optical clarity, dimensional stability, moldability and weight saving advantages over glass. However, their relatively low toughness and the presence of residual molding stress make them prone to crack initiation during mechanical fastening. During its installation, crack formation was consistently observed around self-tapping screw interfaces, raising concerns over reliability, maintainability, and compliance with durability requirements. A structured Design of Experiments (DOE) was performed to identify root causes and evaluate potential mitigation methods. The investigation revealed that residual stresses in the COP material, combined with localized stress concentrations during screw tightening, were the primary drivers of crack initiation. Two complementary process improvements were identified and validated as part of mitigation plan: (i) annealing of the optics prior to assembly to relieve internal stress, and (ii) using step-torquing method to fasten the screws, to gradually distribute applied loads and reduce localized stress peaks. Post-assembly observation over three days confirmed a significant reduction in crack initiation. The combined annealing and step-torquing approach demonstrated a substantial reduction in crack generation probability, providing a practical and repeatable process for enhancing the robustness of polymeric optic assemblies. This work contributes a generalizable methodology for mitigating assembly-induced failures in advanced polymer materials and supports broader adoption of lightweight, high-performance optics in aerospace applications.
S, Nikhil, Singh, Abhimanyu Kumar, Katageri, Praveen, SP, Pradeep, Chandra, Praveen
Advanced Silicone Materials for Harsh Aerospace EnvironmentsTBMG-553046/1/2026
Advanced Silicone Materials for Harsh Aerospace Environments26AERP06_016/1/2026
Aerospace and defense systems demand materials capable of maintaining performance under extreme environmental and operational stressors, including wide thermal cycling ranges, exposure to hydrocarbon fuels, vacuum conditions, and repeated mechanical strain. Silicone-based materials have become essential in these environments because they can retain elasticity, stability, and functionality where many traditional materials fail. Silicones are widely used as coatings, adhesives, sealants, and elastomers in aircraft and spacecraft applications. Their chemical structure enables resistance to both high and low temperatures, while also providing durability against solvents and fuels such as jet fuel. In contrast, many conventional elastomers degrade under prolonged thermal exposure or become brittle at cryogenic temperatures.
Researchers Turn Recovered Car Battery Acid and Plastic Waste Into Clean HydrogenTBMG-552586/1/2026
Researchers have developed a solar-powered reactor to break down hard-to-recycle forms of plastic waste – such as drinks bottles, nylon textiles and polyurethane foams – using acid recovered from old car batteries, and converting it into clean hydrogen fuel and valuable industrial chemicals.
Polymer vs. Metal Seals: A Comparison In Critical Space SystemsTBMG-553016/1/2026
Using Digital Twins to Teach Robots to Lunar CrawlTBMG-552856/1/2026
The future of Moon exploration may be rolling around a non-descript office on the CU Boulder campus. Here, a robot about as wide as a large pizza scoots forward on three wheels. It uses an arm with a claw at one end to pick up a plastic block from the floor, then set it back down.
Polyamide AerogelsTBMG-552896/1/2026
Sometimes referred to as “solid smoke,” aerogels are the world’s lightest solid materials, composed of approximately 85 percent air by volume. Polyamide aerogels open up a whole new world of applications due to their unique properties: translucent like silica aerogels; thermoplastic; ultra-low density; superior mechanical properties; low-temperature operating range; and highly flexible (as compared to NASA Glenn’s polyimide aerogels). Polyamide aerogels are further novel because of their tunable glass transition temperatures, meaning that crystallinity, and hence strength, can be controlled via operating temperature. Addressing the key drawbacks of aerogel technology (hydroscopicity, fragility, cost), NASA Glenn’s suite of organic aerogels are cost-competitive with both existing silica aerogels and, with scale-up, high-end foamed polymer insulation.
Fabrication of Ultrathin Polyimide Optical Filter Films2026-99-17115/22/2026
Polyimides are a class of polymers with imide rings in their main chains. They are renowned for their exceptional mechanical properties, high-temperature resistance, low-temperature endurance, and resistance to chemical solvents, which allow for long-term use under harsh medical operating conditions. Consequently, research on polyimide films has garnered widespread attention. In this study, a two-step method was employed to simplify and optimize the preparation process of polyimide. Initially, a polyamic acid (PAA) solution was prepared, and PAA films were fabricated using a spin coater. Subsequently, the films were imidized to obtain polyimide (PI) films. The impact of various parameters, such as spinning speed, layer number, and temperature, on the film-forming properties of polyimide was investigated using the method of controlling variables. The findings indicate that by setting the spin coater parameters to 700 revolutions per minute (r/min) for 90 seconds, followed by a transition to a high speed of 2200 r/min for 210 seconds for spinning the PAA solution, and then subjecting the film to a temperature gradient of 100°C for 1 hour, 150°C for 1 hour, 200°C for 2 hours, and 300°C for 2 hours for imidization, a complete and mechanically robust polyimide film can be produced. The average light transmittance of the film across a wavelength range of 400-2500 nm is 90.46%.
Huang, Jiehao, Xu, Zihui, Zhao, Kaihong, Lin, Qiting, Hu, Wenzhong, Wang, Liying
Impregnation of Dry Fabric and Ply Lay-UpARP5319 (Current)5/20/2026
This SAE Aerospace Recommended Practice (ARP) describes and gives general guidelines on use and applicability of standard methods for impregnating dry fabric and lay-up of the impregnated plies. The methods of impregnating dry fabric and ply lay-up described in this document have specific application and are not interchangeable. The methods should only be used when specified in an approved repair procedure or with the agreement of the Original Equipment Manufacturer (OEM) or regulatory authority.
AMS CACRC Commercial Aircraft Composite Repair Committee
Heat Application for Thermosetting Resin CuringARP5144A (Current)5/20/2026
This SAE Aerospace Recommended Practice (ARP) describes standard methods of heat application to cure thermosetting resins for commercial aircraft composite repairs. The methods described in this document shall only be used when specified in an approved repair document or with the agreement of the Original Equipment Manufacturer (OEM) or regulatory authority.
AMS CACRC Commercial Aircraft Composite Repair Committee
Unidirectional Carbon Fiber Tape Epoxy Repair Prepreg, Vacuum Curing Part 5 - Material Specification for Unidirectional Carbon Fiber Tape Epoxy Prepreg for Repair and Film Adhesive for Repair, 120 to 145 °C (250 to 290 °F) CuringAMS6885/5 (Current)5/7/2026
AMS6885/5 is the Material Specification (MS) which defines the requirements of a unidirectional carbon fiber tape epoxy repair prepreg capable of curing under vacuum for repair of carbon fiber reinforced epoxy structures. It also defines the requirements of an epoxy film adhesive to be applied in a co-bonding process with the prepreg for solid laminate and sandwich bonding.
AMS CACRC Commercial Aircraft Composite Repair Committee
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