Multifunctional nanocomposite coating for wind turbine blades

In this study, multifunctional carbon nanofiber (CNF) paper-based nanocomposite coating was developed for wind turbine blades. The importance of vibration damping in relation to structural stability, dynamic response, position control, and durability of wind turbine blades cannot be underestimated. The vibration damping properties of the nanocomposite blades were significantly improved and the damping ratio of the nanocomposite increased by 300% compared to the baseline composite. In addition, the CNF paper-based composite exhibited good impact-friction resistance, with a wear rate as low as 1.78×10^?4mm³/Nm. The nanocomposite also shows the potential to improve the blockage of water from entering the nanocomposite, being a superhydrophobic material, with a contact angle higher than 160.0°, which could improve the longevity of a wind turbine blade. Overall, multifunctional nanocomposite coating material shows great promise for usage with wind turbine blades, owing to its excellent damping properties, great friction resistance, and superhydrophobicity.     

兆瓦级风力发电机叶片用环氧树脂

针对兆瓦级风机叶片用纤维/环氧复合材料的特殊要求,开展了适用于真空辅助灌注(VARTM)工艺的环氧基体树脂的国产化研究。采用国产环氧树脂与实验室自制的稀释剂制备环氧树脂与胺类固化剂配合使用,通过示差扫描量热分析,IR光谱,力学性能,耐热性、粘度及吸水性测试等研究了环氧树脂与固化剂配比对其工艺和固化物性能的影响,获得了初始粘度低、粘度对温度不敏感、操作时间长的环氧基体树脂,其树脂浇注体的拉伸性能、弯曲性能均优于国外环氧树脂固化体系,可满足兆瓦级风机叶片用高性能复合材料的使用需求。     

风力发电机叶片用环氧树脂复配体系的研究

采用CYD-128(E1)、双酚F环氧树脂(E2)、己二醇二缩水甘油醚(E3)为主要原材料配制可用于真空灌注的环氧树脂体系,通过粘度和拉伸、弯曲性能测试及示差扫描量热分析研究了树脂体系的流变特性,固化物力学性能和耐热性。结果表明,E1,E2,E3的质量比为65∶15∶20,固化剂为CYDHD-501,固化条件为70℃/6 h时,体系初始粘度较低,工艺性好,固化后力学性能、热性能优异,能够满足1.5 MW风电叶片用环氧树脂指标要求。     

风力涡轮机叶片作为水泥生产用替代原燃材料

据《Global Cement Magazine》2021 年第2期报道,2020年12月8日,北美Veolia公司与通用电气可再生能源公司签署协议,在美国回收其陆上风力涡轮机叶片.这份回收合同是该国风力涡轮机行业的第一份此类合同,将把叶片用作水泥生产的原燃材料.     

PPGHYBON 2026玻璃纤维获风电叶片设计商aerodyn公司认证

PPG工业公司(纽约证交所代号:P PG)近期正式宣布其HYBON2026玻璃纤维无捻粗纱产品获得行业龙头企业--aerodyn的认证,证明HYBON2026玻纤可以作为原材料应用于其指定的玻纤织物中,并与环氧树脂匹配,用来生产1.5兆瓦、2.0兆瓦和2.5兆瓦级aerodyn叶片。aerodyn是全球领先的独立工程公司,专注于风力发电机与叶片的研发。     

世界风能及其叶片材料发展概况与趋势

简述了世界风能及其风力发电叶片和材料的发展概况和趋势，提出了我国的差距和未来发展的建议。     

Thermo-mechanical simulation of ultrahigh temperature ceramic composites as alternative materials for gas turbine stator blades

The efficiency of the Bryton cycle strongly depends on the maximum temperature of the cycle. However, restrictions on metallurgical problems deprive engineers from the benefit of high temperatures. Ultrahigh temperature ceramics can be considered in such cases, instead of traditional materials like M152 superalloy. In this study, SiC reinforced HfB₂ and ZrB₂ ultrahigh temperature ceramics were proposed as gas turbine stator blades. The heat transfer and stress-strain equations were solved numerically by the finite element method to obtain temperature and stress distributions. The results showed that the maximum thermal stress occurs in vicinity of the cooling ducts where the temperature gradient is maximum. The maximum displacements of 1.2 mm (for HfB₂–SiC) and 1.14 mm (for ZrB₂–SiC) occur in the upper wall. It can be noticed that the ZrB₂–SiC made blade showed lower maximum stress and displacement than those for the HfB₂–SiC made one, as a result of lower expansion coefficient of ZrB₂–SiC system. The addition of SiC to monolithic HfB₂ and ZrB₂ ceramics decreases their thermal conductivity and following that, the temperature uniformity in blades reduces. Although the thermal stresses and the probability of failure in these stator blades enhance, the ZrB₂–SiC material presented the best performance among the other investigated samples. Both Coulomb-Mohr and Von Mises failure analyses were employed. It was understood that both blades made of HfB₂–SiC and ZrB₂–SiC composites simply withstand the applied stresses with the safety factors of about 1.5.     

Mechanical characterization and damage assessment of thick adhesives for wind turbine blades using acoustic emission and digital image correlation techniques

Adhesives play a key role in the structural integrity of the Wind Turbine Blades as they are one of the main load carrying materials. A deep knowledge of the adhesives' mechanical behaviour in terms of failure mechanisms and damage processes enhances the attempt to optimize the blade design. Therefore, a comprehensive experimental programme was performed in order to determine the static mechanical properties of the adhesives. Ultimate tensile strength, ultimate compression strength, ultimate shear strength and the elastic properties of the adhesive specimens were determined through tensile and compression tests on dogbone specimens and single-lap bonded joints. The Acoustic Emission (AE) technique was used to relate the acoustic activity in the specimens to their damage state. More specifically, a frequency-based methodology, analysing the AE data, was used for the identification of the different damage mechanisms into the material during the loading. In addition, Digital Image Correlation technique, as a full-field technique, was used to measure displacements and deformations.     

Time-temperature-transformation (TTT) cure diagrams: Relationships between Tg,cure temperature,and time for DGEBA/DETA systems

Isothermal curing of a bisphenol A diglycidyl ether-based epoxy-resin-based, using an aliphatic polyamine, has been performed at temperatures between 20 and 60°C. Samples were cured isothermally at various intervals of time, and analyzed by differential scanning calorimetry (DSC). The glass transition temperature (T_g) and the conversion ratio cure determined by residual enthalpy analysis is used as an isothermal cure-controlled reaction. A time-temperature-transformation (TTT) isothermal cure diagram was carried out to include the time to vitrification and iso-T_g curves. © 1996 John Wiley & Sons, Inc.     

MMA基混凝土修补材料的变形、强度及耐久性

MMA基混凝土修补材料是由甲基丙烯酸甲酯(MMA)和引发剂、增塑剂等合成的高分子聚合物,粘度小且可以通过聚合度的控制进行调整,适宜于细裂纹的修复与修补。研究表明,改性MMA基修补材料收缩接近为0;拉伸强度为46MPa,抗弯强度为90MPa,与砂浆的粘结强度为3 25～9 85MPa;紫外光照射一个月,修补材料的强度可以保持99%;经高温热震和低温热震循环300次后,修补材料的拉伸强度减小为21 56MPa和17 1MPa,弯曲强度减小为40 4MPa和32 5MPa,但仍然远远大于水泥混凝土的强度。     

3D printing ceramic cores for investment casting of turbine blades,using LCD screen printers: The mixture design and characterisation

The primary objective of this study is to demonstrate the possibility of developing silica, alumina, and zircon-based photocurable ceramic suspensions that can be used for visible light photopolymerization (> 450 nm) and to optimise the binder formulations for the purpose of LCD-based ceramic 3D printing applications. Reference ceramic components for this work are ceramic cores employed in the investment casting of high-pressure turbine blades and vanes. Arguably, one of the most critical steps in photoinduced ceramic 3D printing is developing suitable ceramic suspensions, having high ceramic loading, low viscosity, and short curing times. Ceramic suspensions with four different novel binder formulations and commercial ceramic powders used in core manufacturing (SiO₂, Al₂O₃ and ZrSiO₄) were investigated to achieve the best trade-off between: (1) their curing performance (cure depth and curing speed), (2) rheological properties of the binder mixtures at the solid loadings of 60 vol.% for SiO₂, 55 vol.% for ZrSiO₄, and 45 vol.% for Al₂O₃; and (3) the green body mechanical properties of the mixtures after printing. The effect of ceramic particles on the selected binders was examined individually, and the correlation between cure depth (C_d), volumetric loading, and curing speed are evaluated. The results show all binders designed in this study provide an adequate cure depth, even at high ceramic loadings. When the curing behaviour of all unloaded binder mixtures from the previous study [1] compared with the 10 vol.% SiO₂ loaded mixtures, the cure depth of all formulated binder mixtures increased 50–55 % and the curing thickness of 60 vol.% SiO₂ loaded suspensions were still slightly higher than their unloaded counterparts. The rheology outcomes indicate that lower viscosity binders always result in lower viscosity of the ceramic loaded inks, even without taking the effect of dispersants into account. Besides, the addition of N-Vinyl-2-Pyrrolidone (NVP) monofunctional monomer to the binder mixtures significantly reduces the viscosity and changes the normally linear relationship of the mix viscosity and its silica loading content. Among the binder formulations loaded with 60 vol.% of SiO₂, the formulation providing the lowest viscosity and highest mechanical property consists of 5 wt.% of NVP, 45 wt.% of HDDA and 50 wt.% of Photocentric 34 resin. Although this binder mixture showed the highest green flexural strength when loaded by 55 vol.% ZrSiO₄, all other mixtures loaded with zircon flour also demonstrated a near-fluid behaviour, below 200 s^?1. In Al₂O₃ loaded mixtures, the HDDA di-functional binder formulations present lowest viscosity and the di- and multifunctional monomer blends (HDDA-Photocentric27) showed the highest mechanical properties when used in a 50/50 ratio. This work summarises the best binder choices for silica, alumina and zircon based ceramic suspensions used in core printing for investment casting applications through LCD screen printing.     

加成型医用高透明液体注射硅橡胶的制备与研究

以八甲基环四硅氧烷(D4)或六甲基环三硅氧烷(DMC)、乙烯基双封头剂、乙烯基环体、六甲基二硅氧烷等为原料,四甲基氢氧化铵为催化剂合成了摩尔质量和乙烯基含量不同的乙烯基硅油;以高含氢硅油、含氢双封头剂、D4合成实验所需的含氢硅油;以白炭黑为填料通过密炼等工序制备了医用高透明液体注射硅橡胶。结果表明,若制备高透明度的医用液体硅胶需要比表面积大于300 m2/g的气相白炭黑为填料,用干法比湿法处理白炭黑效果好且符合FDA等医用要求,当铂金质量分数为(2.0~2.5)×10-5,抑制剂质量分数为0.10%~0.16%时,能够满足液体注射成型硅橡胶的加工性能和成型周期性。     

Ceramic shell moulds with zircon filler and colloidal silica binder for investment casting of shrouded low-pressure turbine blades

Zircon (ZrO₂·SiO₂) powder filler and colloidal silica binder were used to prepare the ceramic shell moulds for investment casting of shrouded low-pressure turbine blades (LPTB). Ceramic slurries were prepared by using two types of colloidal silica binders (polymer-free binder A and polymer-containing binder B). The samples prepared from binder B showed lesser self-load sag values than those developed from binder A. Ceramic shell moulds made from an optimized slurry composition (having binder A) yielded aeronautical grade casting of blades at 1500 °C with required dimensional accuracy and average surface roughness (Ra). The blades cast from shell moulds (having binder B) showed dimensional accuracy at 1500 °C as well as at 1525 °C. The Ra values of blades cast at 1500 °C and 1525 °C by using shell system with binder B were observed to be higher than those cast from shell system having binder A.     

A simple,inexpensive, real‐time interferometric cure monitoring system for optically cured polymers

Optically cured polymers play a crucial role in many commercial applications, ranging from UV‐cured inks, coatings, and dental fillings to the optical fabrication of three‐dimensional prototypes by means of stereolithography. However, our understanding of the detailed processes that occur in the curing of these materials is often limited by the practical difficulty of observing the cure process in real time, under “real‐world” conditions. This article reports the simple implementation of a free‐space Mach‐Zehnder interferometer that can be constructed inexpensively from readily available components, and demonstrates its utility in monitoring the UV curing of a typical acrylate photopolymer system in real time. In particular, it is shown that this system can sensitively track the induction period, the light‐induced photopolymerization reaction, and the subsequent dark reaction that continues after the irradiation has been halted. This Interferometric Cure Monitor, or “ICM,” thus provides a valuable addition to other analytical methods, both for improving the quality control of existing commercial processes and for aiding the development of improved photopolymer formulations. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Microstructure evolution and mechanical properties of ceramic shell moulds for investment casting of turbine blades by selective laser sintering

Ceramic shell moulds fabricated by traditional shell-making technology have relatively low strength, and often crack during the casting process due to the low strength. In addition, the traditional shell-making process requires long period and high cost. In this work, qualified mullite ceramic shell moulds with enhanced strength were fabricated by selective laser sintering (SLS) combined with high-temperature sintering process. The effects of SLS process parameters on dimensions were investigated, and process optimization was proposed by orthogonal experiments. The effect of sintering temperature on strength at room temperature and 900?°C were studied. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) analysis suggested that mullitization behavior was influenced by sintering temperature. Furthermore, the content of mullite phase, mullite grain sizes, and mean length-diameter ratio of the mullite grains increased with the sintering temperature. Mechanical testing results showed that the samples sintered at 1610?°C had an excellent compressive strength of 99.01?MPa at room temperature and over 172.02?MPa at 900?°C. These values far exceed those of ceramic shell moulds fabricated by the traditional shell-making process (40.43?MPa).