板锥网壳结构的设计与施工

板锥网壳结构是一种受力性能合理,技术经济效益良好的新型空间结构形式。本文对板锥网壳结构的设计与构造、施工与安装进行探讨,着重研究了复合材料层合板的设计计算,提出了种适用于板锥网壳结构的新型节点形式。     

航空航天轻质复合材料壳体结构研究进展

轻质复合材料壳体结构具有轻质、高强及可设计性等优点,被广泛地应用在航空航天结构中.轻质复合材料壳体结构包含网格壳体结构、加筋壳体结构和夹芯壳体结构.本文首先针对这几种轻质复合材料壳体结构从制备方法到力学性能表征方面进行概述,制备方法主要包括纤维缠绕工艺、模压工艺和嵌锁组装工艺等,力学性能方面包含失效模式、动力学性能和阻...     

夹层复合材料在潜艇声隐身结构中的应用及其相关技术研究

本文对复合材料在潜艇声隐身结构中的应用情况进行了分析,对其材料、结构形式、作用效果等方面进行了详细阐述,提出了夹层吸声复合材料作为水下声隐身结构的发展趋势。然后利用数值计算的方法,对夹层复合材料的声学性能进行了分析,得到了夹层复合材料各层材料参数,如厚度、声特性阻抗和损耗等对声学性能的影响规律。最后,评估了典型局部结构壳板应用夹层复合材料后的力学性能和声隐身性能。结果表明,潜艇非耐压结构的壳板采用夹层复合材料可以满足结构的力学要求,与钢结构相比声隐身能力大大提高。     

爆炸荷载作用下复合材料加筋板的动力响应

为了减轻抗爆结构质量,采用玻璃纤维增强聚合物基复合材料（SMC）与碳纤维增强聚合物基复合材料（CFRP）预浸料,通过数值模拟和等效计算理论,对传统加筋抗爆板结构进行轻质高强设计。利用LS-DYNA有限元数值模拟软件进行分析,发现在爆炸荷载作用下加筋板的运动以弹性运动为主,该种复合材料具有较好的抗爆性能。对复合材料加筋板结构进行参数化分析,发现在爆炸荷载作用下横筋对加筋板结构最大位移值影响最大,纵筋和面板对加筋板的影响依次减小。结合刚度折算方法,建立了爆炸荷载作用下正交异性加筋板结构动力响应分析理论。利用该理论计算得到板结构在爆炸荷载作用下的最大位移,与数值模拟对比发现两者结果较为接近,为加筋抗爆板的设计提供了一种简化有效的计算方法。     

J型加筋壁板结构轴压试验及承载能力数值预测

设计了复合材料J型加筋板轴压试验件形式和加载方式,试验研究了其承载能力和破坏形式,讨论了轴压下复合材料加筋板件承载能力预测的有限元建模和分析方法,数值分析了加筋板屈曲和后屈曲模式,结果表明如果不考虑损伤累积对结构承载能力的影响,预测值将明显偏高;而通过引入逐步破坏准则,考虑了基体破坏、纤维基体剪切失效以及纤维断裂等损伤累积对结构承载能力的影响,可以提高数值预测精度。     

黏弹性复合材料阻尼板的振动特性

为深入探索黏弹性复合材料阻尼板的振动特性,基于复合材料力学理论、一阶剪切变形理论、分段位移模型以及哈密尔顿原理,推导了黏弹性复合材料阻尼板结构复数形式的振动微分方程。采用纳维法得到满足位移边界条件的理论解,通过有限元建模仿真对理论解进行验证。基于验证过的理论模型,进一步从理论上探索了黏弹性复合材料阻尼板振动特性随结构参数的变化规律。     

空心光纤在复合材料断裂位置测量中的研究

损伤监测与断裂修复是复合材料研究的难题之一。利用空心光纤注胶来实现复合材料的自诊断、自修复是一种行之有效的方法。由此对空心光纤的传光机理做了详细的研究和分析,并介绍了利用空心光纤对复合材料断裂位置进行测量的原理、方法及实验研究。首先给出了空心光纤的性能,其次介绍了利用测量光纤衰减特性的剪断方法来进行复合材料断裂位置的研究,最后介绍了Y型耦合器在断裂位置研究中的实用性,并以一个系统的实验原理图作为整个研究的小结。     

复合材料褶皱夹芯结构研究进展

复合材料褶皱夹芯结构是通过二维材料折叠而成的三维周期性空间结构,作为一种新型的夹芯结构,具有轻质、高比强度、高比刚度、芯子空间贯通及多功能潜力等优势。本文结合飞行器结构轻量化和多功能化要求,对近年来复合材料褶皱夹芯结构的主要研究成果与特点进行了总结和分析。阐述了复合材料褶皱夹芯结构的构型优化方案及制备工艺,重点归纳了复合材料褶皱夹芯结构的力学性能及多功能的研究现状,包括结构的准静态力学性能、抗冲击性能及隔声、热防护、隐身性能等。基于国内外研究现状,对未来复合材料褶皱夹芯结构的重点研究方向进行了展望。      

碳纤维复合材料抽油杆研究进展

碳纤维复合材料抽油杆是近几年兴起的一种新型柔性抽油杆,具有轻质、高强度、耐高温、耐腐蚀、耐疲劳及结构功能一体化等优异性能,成为解决传统抽油杆失效问题很有发展前途的重要方法之一。主要综述了3种不同树脂基体的碳纤维复合材料抽油杆,包括:环氧树脂基、乙烯基酯树脂基、酚醛树脂基的制备及应用。由于传统的抽油杆很难满足高腐蚀油井、深井以及超深井的开采要求,对碳纤维复合材料抽油杆的发展方向进行了展望。     

钢材与复合材料多形式加筋平板透声性能消声水池实测分析

以复合材料声呐导流罩加筋板结构多目标综合优化为工程背景,开展消声水池模型插入损失测试,横向对比分析钢制桁架筋材与四种复合材料筋材加筋板近场透声特性,综合讨论了筋材材质、筋材结构形式以及入射角度对加筋板近场透声性能的影响。测试及分析结果表明:桁架式加筋板近场透声性能优异且稳定;细矮型筋材可提高加筋板整体透声性能。研究结果为声呐导流罩复合材料加筋板结构的优化设计提供了参考。     

防热复合材料发展与展望

以烧蚀型防热复合材料、 非(微)烧蚀型防热复合材料、 高温高效隔热复合材料以及高温透波复合材料为重点, 简要总结了国内外防热复合材料发展现状, 介绍了我国重点领域的突破与进展, 并展望了未来防热复合材料的发展趋势。      

Enhancing the Deformation of Shape Memory Sandwich Panels

Abstract: Composite sandwich panels fabricated using a thermosetting shape memory polymer matrix material and a corresponding thermoset shape memory polymer foam core offer the potential to demonstrate large, recoverable, deformations in otherwise stiff structures, under flexural loading. However, as with flexure of thin, fibre‐reinforced shape memory matrix laminates, deflection is limited by fibre compression buckling because of the reduced shape memory matrix stiffness at elevated temperature. A hybrid matrix concept has been developed for sandwich panels loaded in flexure in a single direction. This concept uses a non‐shape memory resin as the matrix for a fraction of the plies on the surface of the facesheet loaded in compression. It is predicted that, at the elevated temperatures required for the generation of deformation in the shape memory structural sandwich panel, the shape memory matrix and foam moduli will be substantially reduced, while the modulus of the non‐shape memory resin will not. Thus, at elevated temperature this effectively leads to a shift of the neutral axis towards the non‐shape memory surface, keeping the low stiffness shape memory matrix material in tension and extending the range of deformation prior to onset of fibre buckling. The experiments performed demonstrate that this hybrid matrix approach enables a three‐fold increase in mid‐span deformation prior to buckling of fibres in the compression surface plies. Furthermore, the force measured to attain the deformed geometry, at elevated temperature, only increases approximately 10–15%, while the magnitude of the force required remains very low. Thus, the hybrid matrix approach functions as predicted and enables the development of sandwich panel structural elements which can undergo large, recoverable deformations.     

A study of continuous filament reinforced aluminum matrix composites

Some principal results of the research work on metal matrix composites at Beijing Institute of Aeronautical Materials, concerning CVD-produced continuous B and SiC filaments reinforced aluminum and its alloys, are summarized. The processing, fiber degradation, interface, mechanical properties and fracture behavior of the composites are discussed.Abbreviations CVD chemical vapor deposition - MMCs metal matrix composites - ROM rule of mixtures     

Structural composites for multifunctional applications: Current challenges and future trends

This review paper summarizes the current state-of-art and challenges for the future developments of fiber-reinforced composites for structural applications with multifunctional capabilities. After a brief analysis of the reasons of the successful incorporation of fiber-reinforced composites in many different industrial sectors, the review analyzes three critical factors that will define the future of composites. The first one is the application of novel fiber-deposition and preforming techniques together with innovative liquid moulding strategies. The second is the combination of these techniques by optimization tools based on novel multiscale modeling approaches, so fiber-reinforced composites with optimized properties can be designed and manufactured for each application. In addition, the third is the enhancement of composite applications by the incorporation of multifunctional capabilities. Among them, electrical conductivity, energy storage (structural supercapacitors and batteries) and energy harvesting (piezoelectric and solar energy) seem to be the most promising ones.     

高分子复合隐身材料的研究进展

在简要介绍高分子复合材料分类的基础上,重点综述了不同高分子复合隐身材料的合成与制备方法及特点,并评述了高分子复合隐身材料在吸波隐身技术上的应用进展,展望了其发展趋势。     

先进复合材料:过去、现在和将来

本文简要回顾了先进复合材料的发展历史。重点评述了聚合物基、金属基、陶瓷基和碳/碳复合材料的最新进展和现状。并对各类先进复合材料的未来进行了展望。     

Hybrid effective medium approximations for random elastic composites

Several popular effective medium approximations for elastic constants of random composites are reformulated in terms of a pair of canonical functions and their transform variables. This choice of reformulation enables easier comparisons of the results of all these methods with rigorous bounds. Furthermore, insight into the various methods gained by taking this point of view suggests a number of new effective medium approximations that, in some cases, are natural variants and/or combinations (i.e., hybrids) of the existing ones, and in other cases are new ones based in part on the bounds themselves. Numerical comparisons are given for several standard inclusion models — including spherical, needle, and penny-shaped inclusions — as well as the penetrable sphere model. Of the various alternatives considered, a new method called the split-step differential (SSD) scheme is one of the more useful ones, as it simplifies the differential scheme by replacing half of this scheme’s integration routines with a simple update formula for the bulk modulus.     

Shape control of NITINOL-reinforced composite beams

The shape of composite beams is controlled by sets of flat strips of a shape memory nickel–titanium alloy (NITINOL). The strips are embedded in the composite fabric of these beams inside sleeves, which are placed on the neutral axes. Prior to their insertion inside the beams, the NITINOL strips are thermally trained to provide and memorize controlled transverse deflections. Proper activation of the shape memory effect of the appropriate strips is utilized to produce controlled shapes of the NITINOL-reinforced beams.

A mathematical model is developed to describe the behavior of this class of SMART composites. The model describes the interaction between the elastic characteristics of the composite beams and the thermally induced shape memory effect of the NITINOL strips. The effect of various activation strategies of the NITINOL strips on the shape of the composite beams is determined.

The theoretical predictions of the model are validated experimentally using a fiberglass composite beam made of 8 plies of unidirectional BASF 5216 prepregs, which are 9.75 cm wide and 21.20 cm long. The beams are provided with four NITINOL-55 strips, which are 1.2 mm thick and 1.25 cm wide. The time response characteristics of the beam are monitored and compared with the corresponding theoretical characteristics. Close agreement is obtained between the theoretical predictions and the experimental results. The obtained results suggest the potential of the NITINOL strips in controlling the shape of composite beams without compromising their structural stiffness.