一氧化碳和苯乙烯交替共聚物的合成与表征

利用乙酸钯和２，２′－联吡啶组成的催化剂体系催化一氧化碳和苯乙烯交替共聚合成出聚（１－氧代－２－苯基丙撑）（ＳＴＣＯ）。采用ＩＲ、ＮＭＲ、元素分析以及广角Ｘ光散射对该聚合物以表征。该共聚物晶体为单斜晶胞，晶胞参数为ａ＝１５．７×１０－１０ｍ，ｂ＝６．１７×１０－１０ｍ，ｃ＝７．４５×１０－１０ｍ，α＝９０．０°，β＝１０４．３°，γ＝９０．０°；晶胞体积为６９７．２×１０－３０ｍ３；空间点群为Ｐ２１／ｃ。此外，对该共聚物热降解进行了初步研究。     

克服纤维桥连对GIC影响的隔离层法

本文分析了纤维桥连产生的原因和它对Ⅰ型层间断裂韧性G_IC的影响,提出了一种克服纤维桥连的“隔离层”法,从试件铺层设计入手,力图将纤维嵌套的可能性减到最低.有限元计算结果表明,隔离层的引入并没有改变层间裂纹尖端的应力分布和应力集中,试件的弯曲刚度计算表明,当隔离层的铺层角取±10°～±20°时,可以使±θ隔离层带来的试件弯扭耦合效应降到最低.实验结果证明了这种方法的可行性.     

YCOB晶体生长与激光倍频性能研究

坩埚下降法沿＜０１０＞和＜００１＞方向生长了直径达到２５ｍｍ的完整透明的Ｃａ４ＹＯ（ＢＯ３）３ （ＹＣＯＢ）晶体．化学腐蚀结果表明，所生长晶体无孪晶或亚晶界等缺陷，晶体尾部的位错密度 不超过１８００／ｃｍ２测量了ＹＣＯＢ的透射光谱，其截止波长为２００ｎｍ进行了ＹＣＯＢ晶体对 Ｎｄ：ＹＡＧ激光的二次倍频实验．通过与ＫＤＰ晶体对比，计算出ＹＣＯＢ晶体的有效非线性系数 在Ⅰ型相位匹配方向（θ，φ）＝（６６．３°，１４３．５°）和（６５．９°，３６．５°）上分别为１．４５ｐｍ／Ｖ和０．９１ｐｍ／Ｖ； 大于ＫＤＰ和 ＬＢＯ晶体．在脉冲宽度１０ｎｓ的 Ｎｄ：ＹＡＧ激光单脉冲辐射下ＹＣＯＢ晶体出现体 损伤的激光损伤阈值不低于８５ＧＷ／ｃｍ２．     

钴掺杂Sr_4Fe_6O_(13)混合导体氧化物结构及透氧测定

用湿化学法合成了Ｓｒ４ＣｏｘＦｅ６－ｘＯ１３±δ系列混合导体氧化物,对其相结构与透氧性能进行了研究．钴离子的引入导致材料中钙钛矿型杂相的出现,Ｘ＝２．０时材料中还产生了ＣｏＯ杂相,ｘ＝２．６时材料呈现钙钛矿型结构．Ｓｒ４Ｆｅ４Ｃｏ２Ｏ１３±δ的相结构还与焙烧温度及环境气氛中的氧浓度密切相关．随着氧浓度的降低,材料从纯相Ｓｒ４Ｆｅ６Ｏ１３结构（纯氧气气氛下）转变为Ｓｒ４Ｆｅ６Ｏ１３结构、钙钛矿型结构和ＣｏＯ共存（空气气氛下）,直至转变为针镍矿结构、 Ｓｒ４Ｆｅ６Ｏ１３结构和 ＣｏＯ共存． Ｓｒ４Ｆｅ６Ｃｏ１３±δ导体膜在ａｉｒ／Ｈｅ氧浓差梯度下的透氧量为 １．５×１０８ｍｏｌ／ｃｍ２·ｓ（８５０℃）,在６５０～８５０℃范围内透氧活化能为７０ｋＪ／ｍｏｌ．     

SOCl_2/TiCl_4引发体系的α-蒎烯/苯乙烯阳离子共聚反应研究 Ⅰ.SOCl_2/TiCl_4的共聚合性能研究

通过对ＳＯＣｌ２／ＴｉＣｌ４引发体系的α－蒎烯（Ｍ１）／苯乙烯（Ｍ２）共聚产物进行ＧＰＣ、１ＨＮＭＲ以及微臭氧化－薄层层析法等分析表征，证明该引发体系能在宽广的单体投料比范围内实现有效共聚。在确认仅生成共聚物的反应条件下，采用Ｍａｙｏ－Ｌｅｗｉｓ式积分法测得该体系在－３０℃、［ＳＯＣｌ２］＝２０ｍｍｏｌ／Ｌ、［ＴｉＣｌ４］＝６０ｍｍｏｌ／Ｌ、ＣＨ２Ｃｌ２溶剂中的竞聚率分别为苯乙烯ｒ２＝２．３１±０．１５；α－蒎烯ｒ１＝０．５２±０．０６。     

数控钢管推动测长系统的研制

本文简要地介绍了“数控钢管推动测长系统”的用途，组成及其工作原理，“数控钢管推动测长系统”主要用于成品钢管的精确测长，在推动过程中实现动态测量，并为喷印作定位对齐准备。本系统由机械推动，数字控制及精密测量三部分组成，主要性能指标为：（１）钢管测长范围：３．９０～１２．７０ｍ（钢管管径Φ１１４～５０８ｎｍ）（２）测长精度：±２．０ｍｍ，（３）测量周期：２０～４５秒／次（连续可调）（４）年稳定性：±２     

用SEM研究表面处理对炭纤维增强复合材料剪切断裂的影响

利用扫描电子显微镜（ＳＥＭ）,对炭纤维表面处理前后,炭纤维增强复合材料（ＣＦＲＰ）的剪切断面的观察,并分析了不同表面处理方法对ＣＦＲＰ的界面性质的影响。结果表明,经气液双效法处理后,ＣＦＲＰ得到高的层间剪切强度（ＩＬＳＳ）,同时表现出二剪和三剪的断裂模式。     

COIL用高反膜总积分散射的测量方案探讨

根据ＣＯＩＬ用反射镜和工作条件，提出了改进的Ｃｏｂｌｅｎｔｚ半球测量０°和４５°入射情况下ＴＩＳ散射的方案，与其它测量方法作了比较．     

废硫化胶粉增韧BMC的实验研究

本文以废硫化胶粉（ＲＰ）作为活性填料来改性不饱和聚酯团状模塑料（ＢＭＣ），系统研究了配方、工艺等因素的影响，以及ＲＰ的增韧作用。结果表明，增韧效果与ＲＰ的预处理工艺、种类、填充量、粒径有关。当单体／ＲＰ＝５０／５０，ＲＰ粒径为０．２８ｍｍ，填充量为２０ｐｈｒ时，ＢＭＣ的冲击强度从５．２ｋＪ／ｍ２提高到１１．４ｋＪ／ｍ２，固化收缩率从０．５％下降至０．１％，而其他物理机械性能基本保持不变。透射电镜、电子探针测试证明，ＲＰ与ＢＭＣ基体在相界面附近能够形成梯度ＩＰＮ，加强了两相界面结合，使冲击强度提高。     

磷酸盐陶瓷Ca_(1-x)Ba_xZr_4(PO_4)_6的制备及其零膨胀组成的耐热冲击性研究

Ｃａ１－ｘＢａｘＺｒ４（ＰＯ４）６（０≤ｘ ≤１,简称ＣＢＺＰ）是由具有相反热膨胀异向性的 ＣａＺｒ４（ＰＯ４）６和ＢａＺｒ４（ＰＯ４）６互溶形成的二元固溶体型ＮＺＰ族陶瓷,其热膨胀系数具有可裁剪性．本研究的主要目的是通过调整组成,制备具有较好耐热冲击性的零膨胀材料．为此,首次用共沉淀法合成了单相的 ＣＢＺＰ系列粉体。分别添加 ３％ＺｎＯ和 ４％ＭｇＯ为烧结助剂,制成Ｔ ＣＢＺＰ系列陶瓷材料,用热机械分析（ＴＭＡ）压缩法测定了试样在２０～１０００℃的平均线膨胀系数ａ２０／１０００,以及加热（２０～１０００℃）和冷却（１０００～４００℃）过程的热膨胀曲线．实验结果表明,添加 ＺｎＯ和 ＭｇＯ时的近零膨胀材料分别为Ｃａ０．８５Ｂａ０．１５Ｚｒ４（ＰＯ４）６（ｘ＝０．１５）和ＣａＺｒ４（ＰＯ４）６（ｘ＝０）,α２０／１０００依次为 ０．６×１０－６／°Ｃ和一０．８×１０－６／°Ｃ,但热膨胀曲线上却由于微裂纹的产生而呈现出较大的滞后环,耐热冲击性不理想．可见,对ＣＢＺＰ系列而言,调整组成虽然能实现零膨胀,但很难消除热膨胀异向性,提高其耐热冲击性的有效途径可能是适当抑制晶粒生长以避免产生过多的微裂纹．     

Edge Delamination and Residual Properties of Drilled Carbon Fiber Composites with and without Short-Aramid-Fiber Interleaf

Edge delamination is frequently observed in carbon fiber reinforced plastic (CFRP) laminates after machining, due to the low fracture toughness of the resin interfaces between carbon fiber plies. In this study, the effects of incorporating tough aramid fibers into the brittle CFRP system are quantified by measuring the residual properties of bolted CFRP. By adding short-aramid-fiber interleaves in CFRP laminates, the residual tensile strength have been substantially increased by 14 % for twill-weave laminates and 45 % for unidirectional laminates respectively. Moreover, tensile failure was observed as the major mode of toughened laminates, in contrast to shear failure of plain laminates. The qualitative FEM results agreed well with the experimental results that edge delamination would cause relatively higher shear stress and therefore alter the failure mode from tensile failure to shear failure.     

Feasibility on fiber orientation detection of unidirectional CFRP composite laminates using one-sided pitch–catch ultrasonic technique

It is important to assess fiber orientation, material properties and part defect because strength and stiffness of composites depend on fiber orientation of CFRP (carbon fiber reinforced plastics). A one-sided pitch–catch setup was used in the detection and evaluation of ultrasonic wave behavior and fiber orientation in the unidirectional CFRP composite laminates. Two Rayleigh wave transducers were joined head-to-head and used in the pitch–catch mode on the surface of the composites. The pitch–catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composite. Especially, one-sided ultrasonic measurement was made with using a Rayleigh wave transducers and the Rayleigh ultrasonic waves were extensively characterized in the CFRP composite laminates. Also, a conventional scanner was used in an immersion tank for extracting fiber orientation information in the unidirectional laminate. Therefore, it is thought that the proposed method is useful to evaluate integrity of CFRP laminates.     

碳纤维无纺布对CFRP层板层间的增韧作用及机制

为了揭示短纤维无纺布对碳纤维增强树脂基复合材料(CFRP)层板层间韧性的影响规律,测试了不同面密度(1.95、3.90、7.80和15.60 mg/cm2)和不同纤维平均长度(0.8 mm和4.3 mm)的碳纤维无纺布增韧的CFRP层板I型层间断裂韧性。实验结果表明:对于不同短纤维增韧的CFRP层板,平均长度为0.8mm的短纤维增韧效果优于平均长度为4.3mm的短纤维,并且面密度为7.8mg/cm2、厚度约为150μm、平均长度为0.8mm的碳纤维无纺布显著提高了CFRP层板的层间断裂韧性,与未改性的CFRP层板相比,其能量释放率最大可提高99%。光学显微镜观察结果表明环氧基体中长度为0.8mm的短纤维具有三维交织结构,该结构可以有效地阻止裂纹的扩展;SEM观察结果表明短纤维从环氧基体中的脱粘和拔出以及短纤维周围环氧基体的塑性变形是CFRP层板的主要增韧机制。研究结论为层板短纤维增韧技术的应用奠定了基础。     

Novel test method for accurate characterization of intralaminar fracture toughness in CFRP laminates

A novel initial crack insertion method, “intralaminar film insertion method”, was proposed to investigate the fracture toughness of unidirectional carbon fiber reinforced plastic (CFRP) laminates when the crack propagates inside the ply and not in the interlayer resin-rich area. Here, a release film was inserted inside a single lamina during the resin impregnation process of prepreg manufacturing. Mode I intralaminar fracture toughness tests were carried out for conventional CFRP laminates and interlayer toughened CFRP laminates. For comparison, two conventional methods were used to introduce initial cracks. One is the “interlaminar film method”, where a release film is inserted between two prepreg plies during the lay-up process. The other is the “machined slit method”, where a slit notch is machined in parallel to the layer of CFRP laminates. It was demonstrated that the proposed “intralaminar film method” can correctly evaluate the intralaminar fracture toughness of both conventional CFRP laminate and interlayer toughened CFRP laminate from the initial value to the propagation value. For this range, it was also found that the intralaminar fracture toughness of interlayer toughened CFRP laminate was the same as that of conventional CFRP laminate. Thus, the intralaminar fracture toughness was not influenced by interlayer toughening.     

Reinforcement effects of MWCNT and VGCF in bulk composites and interlayer of CFRP laminates

The reinforcement effects of two nanofillers, i.e., multi-walled carbon nanotube (MWCNT) and vapor grown carbon fiber (VGCF), which are used at the interface of conventional CFRP laminates, and in epoxy bulk composites, have been investigated. When using the two nanofillers at the interface between two conventional CFRP sublaminates, the Mode-I interlaminar tensile strength and fracture toughness of CFRP laminates are improved significantly. The performance of VGCF is better than that of MWCNT in this case. For epoxy bulk composites, the two nanofillers play a similar role of good reinforcement in Young’s modulus and tensile strength. However, the Mode-I fracture toughness of epoxy/MWCNT is much better than that of epoxy/VGCF.     

碳纤维增强环氧树脂复合材料层合板结构及间隙尺寸对铆接性能的影响

通过对不同纺织结构的碳纤维增强树脂基复合材料（CFRP）层合板与铝合金（AlMg3）异质材料连接结构进行单剪切拉伸研究,分析间隙尺寸对不同纺织结构CFRP层合板与AlMg3连接结构性能的影响。试验结果表明,当CFRP层合板铺层数目相同时,对于纺织结构不同、间隙配合尺寸相同的CFRP-AlMg3单铆钉单剪切连接结构,编织结构碳纤维增强树脂基复合材料（WO-CFRP）层合板所受挤压应力比非编织结构碳纤维增强复合材料（UD-CFRP）层合板所受挤压应力大25%左右;对于纺织结构相同、间隙配合尺寸不同的CFRP-AlMg3单铆钉单剪切连接结构,其各自铆钉所受剪切应力和连接CFRP层合板所受挤压应力相差不大。同时对相同间隙尺寸、不同纺织结构的CFRP-AlMg3单铆钉单剪切连接结构各个阶段挤压应力分析得知：其他条件一定,各个阶段中WO-CFRP的挤压应力比UD-CFRP的挤压应力高20%左右。最后研究间隙尺寸对CFRP-AlMg3单铆钉单剪切连接结构性能的影响,发现铆钉与孔壁间隙尺寸对位移为铆钉直径大小的4%时的CFRP层合板受到的挤压应力影响较大,铆钉与孔壁间隙大小增加0.1 mm,位移为铆钉直径大小的4%时的CFRP层合板受到的挤压应力降低约17%,而对CFRP层合板的初始损伤应力和破坏应力几乎没有影响,对铆钉所受剪切作用力和AlMg3板材所受挤压应力也几乎没有影响。     

Evaluation of thermo-viscoelastic property of CFRP laminate based on a homogenization theory

The thermo-viscoelastic constitutive equation of unidirectional carbon fiber reinforced plastic (CFRP) is evaluated using a numerical approach based on the finite element method (FEM) and homogenization theory. The constitutive equation of the CFRP is considered in the Laplace-transformed domain, and it is discussed on the basis of the correspondence principle, which is satisfied by each of the Laplace-transformed elastic moduli. Homogenization theory is employed to estimate the ‘homogenized elastic moduli’ of the composite composed of matrix resin and carbon fibers. Using the approximation of a generalized Maxwell model, the relaxation moduli of CFRP are obtained by numerical computation using the FEM. From the relaxation modulus of epoxy resin and elastic moduli of carbon fiber, thermo-viscoelastic properties of CFRP laminates at several temperatures can be estimated using the FEM with homogenization theory. The effectiveness of the present study is verified by comparing the experimental results and numerical calculations for the relaxation moduli of the CFRP laminates.     

Prediction of initiation of transverse cracks in cross-ply CFRP laminates under fatigue loading by fatigue properties of unidirectional CFRP in 90° direction

A fatigue life to the initiation of transverse cracks in cross-ply carbon fiber-reinforced plastic (CFRP) laminates has been predicted using properties of the fatigue strength of unidirectional CFRP in the 90° direction. In the experiments, unidirectional [90]₁₂ laminates were used to obtain a plot of maximum stress versus number of cycles to breaking, and two types of cross-ply laminates of [0/90₄]_S and [0/90₆]_S were used to evaluate the initiation and multiplication of transverse cracks under fatigue loading. Transverse cracks were studied by optical microscopy and soft X-ray photography. Analytical and experimental results showed good agreement, and the fatigue life for transverse crack initiation in cross-ply laminates was predicted successfully from the fatigue strength properties of the unidirectional CFRP in the 90° direction. The prediction results showed a conservative fatigue life than the experimental results.     

Strength evaluation of unidirectional carbon fiber-reinforced plastic laminates based on tension–compression biaxial stress tests

Biaxial stress tests of carbon fiber-reinforced plastic (CFRP) laminates were performed to investigate failure criteria under biaxial loads. Specimens of unidirectional CFRP laminates were subjected to a tensile load in the longitudinal fiber direction and a compressive load in the transverse fiber direction. An exclusive jig was used to perform biaxial stress tests with a commonly used single-axis testing machine. Measurements were obtained by controlling the displacement ratio between compressive and tensile displacements. The critical tensile and compressive stresses were then calculated using a constitutive equation. The critical longitudinal tensile stress markedly dropped with increasing the compressive load. The failure criteria of the biaxial stress tests were expressed as the ellipse, of which the major and minor axes were the longitudinal tensile/transverse compressive strengths or fracture strains, respectively. Scanning electron microscope observations suggest that fiber/matrix interfacial debonding due to the compressive load could decrease the critical longitudinal tensile stress.     

A comparative study of failure features in aerospace grade unidirectional and bidirectional woven CFRP composite laminates under four‐point bend fatigue loads

Damage mechanisms in unidirectional (UD) and bi‐directional (BD) woven carbon fiber reinforced polymer (CFRP) laminates subjected to four point flexure, both in static and fatigue loadings, were studied. The damage progression in composites was monitored by observing the slopes of the load vs. deflection data that represent the stiffness of the given specimen geometry over a number of cycles. It was observed that the unidirectional composites exhibit gradual loss in stiffness whereas the bidirectional woven composites show a relatively quicker loss during stage II of fatigue damage progression. Both, the static and the fatigue failures in unidirectional carbon fiber reinforced polymer composites originates due to generation of cracks on compression face while in bidirectional woven composites the damage ensues from both the compression and the tensile faces. These observations are supported by a detailed fractographic analysis.