三维缝合复合材料性能研究

介绍三维缝合复合材料的制造方法及工艺参数对性能的影响，研究层间断裂韧性和冲击损伤容限。     

复合材料缝合技术的研究进展

为更好了解复合材料缝合技术的研究现状,简述了缝合方式、缝合参数和近年来缝合复合材料力学性能的研究近况,以及国内外缝合设备的发展和应用。总结了缝合技术对复合材料力学性能的影响,证明缝合在材料的厚度方向引入连续纤维,可增强复合材料的层间断裂韧性,提高冲击损伤容限;分析了缝合系统和机器人相结合的发展现状,可在现有设备的基础上,不断创新新型设备,推动实现复合材料缝合技术的高效化、智能化;最后提出缝合技术目前发展存在的挑战及机遇,并指出复合材料缝合技术在航空航天、新能源、汽车等领域的发展前景。     

缝合参数对经编双轴向织物增强复合材料树脂流动性能的影响

简介VARTM工艺以及缝合复合材料。通过改变几种缝合工艺参数如针距、行距、缝合线的线密度、缝合方向等,观察以上参数的变化对经编双轴向织物增强复合材料充模过程中树脂流动性能的影响,并分析了缝合参数变化影响树脂流动的原因。     

缝合复合材料的研究进展及其在海洋领域的应用

随着海洋资源的大力开发,复合材料在海洋领域的应用得到了迅速发展。传统的层合复合材料的层间性能较弱,缝合工艺可有效地改善其层间性能。针对海洋环境的特点,综述了海洋环境下缝合复合材料的研究现状,分析了海洋环境和缝合工艺对缝合复合材料的层间性能、抗冲击性能以及面内性能等的影响及其作用机制。概述了缝合复合材料在船舶、船舶配件、海上风力发电机和海底汽油田平台设备等领域的潜在应用。最后,总结了缝合复合材料在海洋环境中进一步应用亟待解决的问题,展望了未来海洋环境中缝合复合材料的发展趋势和应用前景。     

缝合技术在复合材料上的应用及发展

缝合复合材料以其优良的层间断裂韧性和冲击损伤容限而越来越受到各国研究者的关注。主要介绍缝合技术在复合材料上应用的发展状况,综述了缝合方式、缝线轨迹和缝合工艺参数及其对复合材料力学性能的影响。     

三维编织复合材料T型梁的低温场弯曲性能

为研究三维编织复合材料T型梁低温环境下的弯曲力学性能,以指导耐低温抗弯曲三维编织复合材料结构设计,采用真空辅助树脂传递模塑成型工艺制备不同筋高高度三维编织复合材料T型梁,自制低温环境箱,与MTS 810.23型材料测试系统相结合测试三维编织复合材料T型梁在不同低温下的弯曲力学性能。结果表明:随测试温度的降低,三维编织复合材料T型梁载荷增加,位移增大,能量吸收增加;随筋高高度的增加,三维编织复合材料T型梁载荷增加,位移减小,能量吸收增加,抗弯刚度增强;三维编织复合材料T型梁由较高温度下不同程度的屈服断裂转变为低温下的脆性断裂,随着筋高高度增加,失效模式由弯曲失效转变为剪切失效。     

缝合对复合材料力学性能的影响

本文对锁式缝合、链式缝合、无缝合三种碳纤维复合材料进行了拉伸、弯曲、短梁剪强度研究,并分析了其破坏模式。结果表明,较无缝合复合材料,锁式缝合、链式缝合两种缝合复合材料拉伸及弯曲强度下降,短梁剪强度上升。     

经编多轴向复合材料拉伸性能的研究

文章介绍了以经编多轴向织物为增强材料的复合材料。对织物、树脂浇铸体以及层合板分别进行了拉伸实验，分析了织物和树脂单体本身所具有的性能，以及两者加工成复合材料后所具有的性能。并通过对单体和复合材料的性能对比，验证了复合材料独特优良性能。     

间隔织物面层组织对其增强板材性能的影响

设计织造平纹、方平、2/2斜纹和1/3斜纹4种不同面层组织的间隔织物,并在间隔织物的空间结构中填充聚氨酯泡沫,再用环氧树脂对其表面进行复合,加工制成机织间隔织物复合材料板材.对加工出来的4种间隔织物的复合板材进行压缩和弯曲试验,探讨4种不同的面层组织对间隔织物复合材料板材性能的影响.     

氨化处理对碳纤维表面性能及其复合材料的影响

利用多乙烯多胺溶液作为涂层液,涂覆在碳纤维表面,然后在600℃热处理30 s,水洗后烘干.采用原位红外光谱仪(FT-IR)、原子力显微镜(AFM)、接触角测定仪研究氨化处理前后碳纤维表面组成、形貌以及浸润性的变化.发现碳纤维经过氨化处理之后其表面形成了氨基官能团且氨基官能团以酰胺类形式存在,表面微小凸起减少,与环氧树脂和水的接触角分别降低了22%和32%.用三点短梁法研究碳纤维处理对复合材料层间剪切强度的影响.发现热处理可使复合材料的层间剪切强度提高6.65%;而氨化处理可使复合材料的层间剪切强度提高24%.力学数据表明氨化处理不会影响碳纤维强度.     

基于边界效应模型的玻璃纤维复合材料准脆性断裂性能分析

为解决玻璃纤维复合材料的准脆性断裂问题,基于边界效应模型,引入玻璃纤维复合材料的单层预浸料厚度作为特征复合材料单元建立解析表达式,在三点弯曲条件下测得带有浅表面刮痕试样的峰值载荷,计算得到准脆性断裂参数:抗拉强度和断裂韧性。经正态分布分析后得到断裂参数均值:抗拉强度为169.48 MPa,断裂韧性为20.34 MPa·m^1/2,在具有95%的可靠性范围内几乎覆盖了全部试验离散点。将试样参数拟合在一起,得到断裂载荷与等效面积的线性拟合曲线,结果表明:使用正态分布法和线性拟合法得到的抗拉强度吻合度较高,二者之间的误差仅为4.95%。     

高速剪切均质改善浆膜性能

为了进一步提高浆膜的性能,采用物理性的高速剪切均质加工方法对各种浆液进行处理,研究浆液高速剪切均质后浆膜性能的变化,探讨纯淀粉浆液、纯PVA浆液以及混合浆液经高速剪切均质后的浆膜性能。试验结果表明:高速剪切均质不仅能改善原淀粉的浆膜性能,更能较大幅度地提高混合浆膜的断裂强度、断裂伸长率、耐屈曲次数等物理机械性能,且在研究范围内剪切时间和剪切转速都与浆膜性能改善的程度成正相关。     

Antimicrobial performance of potassium sorbate supported in tapioca starch edible films

The release and antimicrobial activity of potassium sorbate (KS) supported in tapioca starch–glycerol edible films prepared by different gelatinization/drying techniques against Zygosaccharomyces bailii was studied. Antimicrobial release in liquid media of different pHs (3.0–6.0) could be approximated to a pseudo first-order kinetic model and was almost accomplished after 30 min. Filmmaking method involving slow gelatinization and drying rate resulted in the highest fraction of KS released at equilibrium. Rate constant was higher when pH of the receiving media was 4.5 and fast gelatinization/fast drying had been used. The effectiveness of the preservative released for controlling the microbial growth depended on the pH of the receiving media, being higher at pH 3.0. No effect of filmmaking method was observed. In relation to film effectiveness as a barrier to contamination, it was observed that the preservative was available to prevent an external Z. bailii contamination and also to control yeast growth in an acidified (pH 4.5) high water activity (a _w = 0.980) semisolid product.     

A critical review of the specifications and performance of antibody and DNA-based methods for detection and quantification of allergens in foods

Despite the availability of a large number of antibody and DNA based methods for detection and quantification of allergens in food there remain significant difficulties in selecting the optimum technique to employ. Published methods from research groups mostly contain sufficient detail concerning target antigen, calibration procedures and method performance to allow replication by others. However, routine allergen testing by the food industry relies upon commercialised test kits and frequently the suppliers provide disappointingly little specification detail on the grounds that this is proprietary information. In this review we have made a critical assessment of the published literature describing the performance of both commercial and non-commercial test kits for food allergens over the period 2008–2018. Mass spectrometric methods, which have the potential to become reference methods for allergens, are not covered in this review. Available information on the specifications of commercial ELISA and LFD test kits are tabulated for milk, egg and peanut allergens, where possible linking to publications concerning collaborative studies and proficiency testing. For a number of commercial PCR test kits, specifications provided by manufacturers for detection of a small selection of allergen are tabulated. In conclusion we support the views of others of the critical need for allergen reference materials as the way forward to improve the comparability of different testing strategies in foods.