防弹用纤维复合材料最佳树脂含量研究

本文针对7. 62mm钢芯弹侵彻高强玻璃纤维复合板时的侵彻机理,研究树脂含量对纤维复合材料力学性能和抗弹性能影响规律,确定了合适的树脂含量,显著地提高了纤维复合板抗弹性能。     

高强玻璃纤维复合材料抗弹近似计算

本文采用试验的方法,建立了高强玻璃纤维复合材料防弹性能近似公式。利用SEA（单位面密度能量吸收）作为评价抗弹能力的指标,它对于复合材料防弹研究以及纤维复合板初步设计有重要的参考意义。     

Vectran纤维复合材料抗破坏性能的研究

为了解Vectran纤维复合材料抗破坏性能,本文测试了Vectran织物及其有机硅涂层织物的拉伸、撕裂、冲击和磨损性能,并分析了涂层对其力学性能的影响。试验得出,Vectran织物轻质高强,其拉伸破坏形式为纱线的断裂和滑移;经涂层工艺加工后,织物中纱线被固定,拉伸破坏主要表现为纤维的直接断裂;涂层使Vectran织物的撕裂强力大大降低,主要是由于涂层使织物的撕裂三角区大大减小,受力纱线根数减小;涂层织物的抗冲击性能远远低于未涂层织物;Vectran纤维的耐磨性能较好,经受砂轮磨损后基本不产生磨屑。     

纬编双轴向多层衬纱织物增强复合材料的弯曲性能研究

本文主要对高性能纤维的纬编双轴向多层衬纱织物增强复合材料的弯曲性能进行研究分析.本文所用的增强纤维为玻璃纤维和高强聚乙烯纤维两种,增强织物包括玻璃纤维织物、高强聚乙烯纤维织物及玻璃纤维/聚乙烯纤维层间混合织物三种,基体为乙烯基酯树脂,文中着重对几种复合材料的弯曲性能进行测试和分析比较.分析结果表明,该类复合材料有很好的弯曲性能,含有玻璃纤维的横向弯曲破坏有其特点,玻璃纤维为脆性破坏,而聚乙烯纤维表现为屈曲破坏.     

高强织物防穿刺作用特征与机制分析

高强织物广泛应用于防刺领域。为了研究高强织物防穿刺作用特征与机制,自行设计了可调重量与高度的自由落体式实验装置,选用单刃刀、三棱刀、锥对芳纶与超高分子量聚乙烯纤维织物进行刺入实验,考察了冲击能量、刀具截面形状、刺入角度对穿刺作用的影响,研究了织物纤维种类、结构、叠层密度与织物防穿刺作用的关系,分析了刀具对高强织物穿刺作用的机制。结果表明,穿刺效果主要由能量的大小决定,受其速度、质量的组成比例影响较小;刀具的截面形状决定其穿刺织物时的剪切破坏与排挤破坏的组成形式;防刺材料的结构是影响其防穿刺性能的关键因素,同种材料不同结构织物抗排挤能力越强。织物对锥和单刃刀的防穿刺能力越强。对三棱刀的防穿刺能力变化不明显。     

聚丙烯纤维和膨胀剂对高强轻质混凝土收缩和抗开裂性能的影响

试验配制了等强的普通混凝土和高强轻质混凝土,为改善高强轻质混凝土的收缩和抗开裂性能,向其中分别单掺、双掺了膨胀剂和聚乙烯纤维.通过自由收缩试验和约束收缩试验研究了聚丙烯纤维和膨胀剂对高强轻质混凝土收缩和抗开裂性能的影响.试验结果表明,聚丙烯纤维和膨胀剂均可以改善高强轻质混凝土的收缩和抗开裂性能;按照本试验的掺量进行双掺,制成的高强轻质混凝土的收缩和抗开裂性能均优于普通混凝土.     

混杂纤维增强高强混凝土性能研究

为研究钢纤维、聚乙烯醇纤维混杂比例对高强混凝土性能的影响,通过合理设计坍落度试验、力学强度试验、收缩试验、抗裂试验、抗氯离子侵蚀试验,对比评价了纤维混杂比例对高强混凝土工作性、抗折强度、收缩性、抗裂性能以及氯离子渗透系数的影响。结果表明,钢纤维和聚乙烯醇纤维降低了新拌混合物的工作性。与单掺纤维相比,混杂纤维对高强混凝土力学性能改善效果不明显,但可明显改善混凝土抗裂性能,开裂面积抑制率最大为95.8%,同时能使高强混凝土收缩率和氯离子分别降低27.7%和66.5%,明显提高高强混凝土的耐久性能。通过扫描电镜试验分析探讨了纤维增强混凝土的作用机理,结果表明混杂纤维对基体内部结构的改善实现了对混凝土宏观性能的提升,最终推荐采用0.75%(体积分数)钢纤维和0.25%(体积分数)聚乙烯醇纤维。     

环氧树脂固化剂对高强玻璃纤维复合防弹板的力学性能影响分析

为高强玻璃纤维复合防弹板的环氧树脂固化剂进行研究。重点研究了三种不同固化剂的种类、用量及环氧树脂分子量对纤维复合板力学性能的影响。研究表明不同牌号、不同分子量的环氧树脂，对纤维复合板力学性能有一定影响。综合考虑选用间苯二胺作为高强玻璃纤维复合防弹板的固化剂。     

高强度耐烧蚀材料工艺性能研究

本文通过添加改性剂提高了酚醛树脂的韧性,对短切高强纤维、定长高强纤维、高强纤维织物、碳布、功能夹层等不同增强方案进行了试验探索.考核了不同材料体系的弯曲性能,进行材料工艺性能研究,模拟静力试验考核不同材料体系试验件的综合强度,实现了产品的工程化应用.     

一种抗蠕变超高相对分子质量聚乙烯纤维混杂织物及其制备方法

本发明涉及一种抗蠕变超高相对分子质量聚乙烯纤维混杂织物及其制备方法。该混杂织物是由超高相对分子质量聚乙烯纤维、碳纤维等其它有机或无机纤维通过混纺或单纺混编而成,本发明利用纤维的混杂效应,综合各种纤维各自的优点,制备成一种可应用于结构件复合材料的抗蠕变超高相对分子质量聚乙烯纤维混杂织物,改善了单一超高相对分子质量聚乙烯纤维的抗蠕变性能及其与基体材料的粘结性能,该织物可应用于需长时间承受载荷的结构件复合材料。     

The effect of sizing on composite properties for materials used in the shuttle filament wound case

An epoxy resin and a sized carbon fiber have been used to produce a light-weight filament wound case for the Space Shuttle. The sizing facilitates fiber handling during winding but may affect the amount of resin absorbed by the fiber during impregnation and the final mechanical properties of the composite. Naval Ordnance Lab rings were wound to study the effect of the sizing content on the resin absorption by the fiber bundles, the final tensile properties of the composite, and the type of failure observed at burst. The resin content of the rings studied was between 20 to 40 percent, and the sizing content, 0 to 1.6 percent by weight. Results showed that the sizing content was a critical parameter which determined the amount of resin absorbed by the fibers. The final tensile strength was dependent on the amount of sizing present. The tensile strength decreased by as much, as 60 percent when a low resin and high sizing content were present. The type of failure at burst was a function of resin content rather than size content.     

High-strength superparamagnetic composite fibers

The polymer composites of magnetic nanoparticles can be possibly used in a bulk form by preserving all the novel characteristics of magnetic nanoparticles such as superparamagnetic behavior. By introducing magnetic properties of Fe₃O₄ nanoparticles into polymer fibers, novel magnetic properties combine with the advantages of composite fibers such as light-weight and ease-of-use. Using dry-jet-wet fiber spinning technology, we have successfully fabricated iron oxide/polyacrylonitrile (Fe₃O₄/PAN) composite fibers with 10 wt% nanoparticle in the polymer matrix. Composite fiber with a diameter as small as 15 μm can achieve tensile strength and tensile modulus values as high as 630 MPa and 16 GPa, respectively. Superparamagnetic properties of Fe₃O₄ nanoparticles were preserved in the composite fibers with saturation magnetization at 80 emu/g and coercivity of 165 G.     

A positron annihilation spectroscopy study of carbon-epoxy composites

Many positron annihilation spectroscopy (PAS) studies have been carried out during the last several years for characterizing various polymeric materials. In this work, the PAS technique is used to investigate some positron annihilation characteristics of the combination of carbon fibers with epoxy polymers to form carbon-epoxy composites. These composites are receiving wide and increasing application in industrial markets where light-weight materials with high strength and excellent fatigue characteristics are required. We have found that PAS is capable of detecting different concentrations of carbon fiber in these composites and a relationship is shown to exist between fiber fractions found by PAS and apparent volume and weight fractions found by density measurements. Positron annihilation centers have also been found that we believe were created at the carbon-epoxy interface when the composite was prepared. Characterization of this interface is important for the development of composites with improved mechanical properties.     

复合造孔剂对刚玉-钙长石-莫来石系轻质浇注料性能的影响

本文以聚苯乙烯小球和炭黑作为复合燃烬添加物,研究复合造孔剂对刚玉-钙长石-莫来石系轻质浇注料性能的影响,并确定了聚苯乙烯小球和炭黑复合的最佳掺量.采用XRD分析了轻质浇注料的物相组成.结果表明:轻质浇注料的主要矿物相是刚玉、钙长石、莫来石和少量玻璃相,随着聚苯乙烯小球和炭黑加入量的变化,轻质浇注料的力学性能得到明显改善...     

A cure-rate model for the shuttle filament-wound case

An epoxy and carbon fiber composite has been used to produce a light-weight rocket case for the Space Shuttle. A kinetic model is developed which can predict the extent of epoxy conversion during the winding and curing of the case. The model accounts for both chemical and physical kinetics. In the model, chemical kinetics occur exclusively up to the time the transition temperature equals the reaction temperature. At this point the resin begins to solidify and the rate of this process limits the rate of epoxy conversion. A comparison of predicted and actual epoxy conversion is presented for isothermal and temperature-programmed cure schedules.     

Mechanical Properties of Natural Fiber Containing Polymer Composites

We have studied the mechanical properties of ethylene vinyl acetate (EVA) and cellulose acetate (CA) composite containing cellulosic natural fibers (Sterculia villosa) and tried to explain with the help of mixing of fiber in the composite. It is observed that the tensile strength (TS) of EVA composite decreases with the addition of fiber. Whereas in a CA composite, TS increases or reinforcement happens with the fiber content. This anomalous trend could be explained with the adhesion of fiber with the polymer matrix in the composite. The composite shows the same increasing trend for flexural strength (FS) up to a certain composition of fiber. With the further addition of fiber, we have found decreasing FS for the EVA composite, but a gradual increase in the CA composite with the fiber content. It is thought that fiber is well distributed in the CA composite and that the fiber-matrix could bear the load resulting in an increase of FS. This consideration can be well explained from the SEM picture that shows fiber forms a domain in the EVA composite or coagulation of fiber, as a result the FS decrease, but there is no such type of coagulation in the CA composite, resulting in increasing TS and FS with the fiber content. Toughness of the composites are also compared. It is believed that the cellulose-containing EVA and CA composites will be environment-friendly. We also suggest that this composite could be used in a low weight application such as gasket materials, toothbrushes, spoon handles, mirror frames, partition panels, etc.     

轻质碳纤维复合材料帆船桅杆的设计与制备

碳纤维复合材料与金属相比,具有重量轻、可设计性强等优点.本文目的是设计并制备轻质碳纤维复合材料桅杆.基于等刚度准则,对具有等壁厚、异型截面的中空碳纤维复合材料桅杆进行设计,并运用数值模拟技术对结构铺层进行优化.采用纤维铺放和缠绕工艺制备出长度为16m的大尺寸碳纤维复合材料帆船桅杆,与铝合金桅杆相比减重43.4%.在设计工况下,桅杆变形试验值与数值模拟结果相近.     

纤维复合材料在装甲防护上的应用

反装甲武器威力的飞速发展,迫使装甲防护材料必须具备轻质高强、优异的防弹性能及耐疲劳等性能.本文首先阐述了在装甲防护上纤维复合材料的优点和防弹机理,其次介绍了国外复合材料在装甲防护上的研究应用现状和新型研制技术,主要包括玻璃纤维、芳纶纤维、UHMWPE纤维以及PBO纤维等复合材料,然后介绍了我国纤维复合材料的研究及应用现状.最后结合我国目前的研制情况,提出了复合材料装甲的研究发展方向.     

高性能纤维增强复合材料应用的研究进展

纤维增强复合材料具有质轻、高比强度和比模量、加工成型性好、耐冲击、耐腐蚀等特性,在轻量化材料领域有着广阔的发展前景,综合对比了玻璃纤维、碳纤维、芳纶及超高相对分子质量聚乙烯纤维等纤维增强复合材料在航空航天、汽车领域、能源工业、环保领域中的应用现状,认为碳纤维增强复合材料在轻量化、高性能化方面具有极大的优势及应用前景。     

Fracture resistance of endodontically treated molars restored with polyethylene fiber and different posts

The purpose of this study was to compare the fracture strength and mode of teeth restored with fiber/titanium post, polyethylene fiber, and adhesive composite. The mesial, distal, and palatal walls of human maxillary molar teeth were removed, so that only the buccal wall remained. Group 1, with caries-free maxillary molars, was used as a positive control group and the remaining groups were restored as follows: group 2, with only adhesive composite; group 3, with polyethylene fiber and adhesive composite; group 4, with fiber post and adhesive composite; group 5, with fiber post, polyethylene fiber, and adhesive composite; group 6, with titanium post and adhesive composite; and group 7, with titanium post, polyethylene fiber, and adhesive composite. A universal testing machine was used for fracture tests. Compressive loads were applied at an angle of 90 degrees on the occlusal surface of the specimens at crosshead speed of 1?mm/min until fracture occurred. Kruskal–Wallis and Mann–Whitney U tests were adopted for statistical analysis. The study shows that, based on the fracture strength, the group of teeth that were restored with glass fiber post, polyethylene fiber, and adhesive composite has the most significant improvement over all the other teeth groups. Based on the fracture mode, the teeth groups restored with only glass fiber post, adhesive composite, polyethylene fiber, and adhesive composite have relatively more restorable fractures observed.