共查询到18条相似文献,搜索用时 93 毫秒
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钛及钛合金由于具有优秀的抗腐蚀性、生物相容性、低密度和高的比强度等特性,而被应用于生物医学方面。然而,与人骨相比,钛合金的弹性模量较高,可达100~110GPa,而人骨的弹性模量只有10~30 GPa。虽然与其它金属材料相比具有与骨较为接近的弹性模量,但仍远远高于骨的弹性模量,这就容易造成钛与人体骨界面上力学性能的不匹配,如直接植入则会带来“应力屏蔽“效应,因此对钛及钛合金进行处理来降低弹性模量和提高活性成为当前研究的热点。目前主要通过两种途径来改善纯钛及其合金的生物活性和生物相容性问题,一种就是通过各种不同工艺在纯钛及其合金表面涂覆羟基磷灰石及生物玻璃涂层,另一种是将生物活性材料HA作为一种活性相混入纯钛及其合金中,形成一种微观复合材料。本文重点介绍了近年来钛基生物复合材料的研究进展。 相似文献
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介绍了镁基复合材料传统的及现代的制备方法、以及各种方法的优缺点和对该材料性能的影响,详细介绍了最新发展的反应性自组织构筑法,指出该方法在制备镁基纳米复合材料上的优势及其对镁基复合材料性能的改善. 相似文献
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环氧树脂是目前应用最为广泛的热固性树脂之一,其固化后会形成不溶、不熔的高度交联的三维网络结构,从而导致树脂及其碳纤维复合材料的降解困难而且难以再加工,造成了严重的资源浪费与环境污染。采用可再生生物质原料制备生物基可降解环氧树脂及其碳纤维复合材料,在缓解能源危机、减轻环境污染和实现资源再利用上具有重要意义。综述了生物基可降解环氧树脂及其可回收碳纤维复合材料的研究进展,主要包括含有热或化学不稳定键的可降解环氧树脂的合成、性能、降解机理及其碳纤维的无损回收,并总结了其优缺点。 相似文献
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小波基特征提取的复合材料损伤检测 总被引:7,自引:0,他引:7
借助小波函数良好的时频带通性,利用B样条小波级数展开提取信号特征,并使之输入到自适应B样条小波神经网络进行学习和识别。最后从损伤检测领域中特征信号模式识别的应用角度,给出了利用上述理论进行复合材料无损检测的实例 相似文献
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目的 近年来,随着消费水平及消费形态的发展,果蔬包装,尤其是鲜切果蔬包装的消费量迅速攀升。相较于传统石油基类包装材料,生物基包装材料拥有环境友好、可持续等特点,是未来果蔬包装材料发展的重要方向。本文拟综述国内外生物基包装材料的研究进展及其在果蔬保鲜中应用,为后续相关领域的研究与应用提供理论参考。方法 首先介绍果蔬的保鲜机制及其包装需求,随后分类论述不同种类生物基材料的特性及制备方式,最后阐述相关生物基材料在果蔬包装中的应用。结论 总结了生物基包装材料在果蔬包装领域的研究进展,并对其未来发展趋势进行展望。 相似文献
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机敏复合材料结构不仅具有复合材料的承载功能,还可通过埋在其中的传感器监测结构的工作状态,本文详细介绍了光纤传感器阵列和声发射传感器阵列两种损伤监测系统的工作有理及应用前景。 相似文献
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The strength of unidirectional composites is often lower in compressionthan in tension, making compressive strength an especially importantdesign criterion. Compressive strength in the fiber direction depends onthe stiffness of the matrix material, which softens over time due toviscoelastic effects, and thus lowers the strength of the composite.This reduction must be accounted for in assessing the long-termdurability of composite structures.The dependence of compressive strength on time and temperature hasbeen investigated for a unidirectional carbon/epoxy composite material.Experimental results for strength versus time are compared withanalytical predictions based on a one-dimensional fiber microbucklingmodel and numerical results from finite element analysis. 相似文献
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Compression Response of Composite Cushioning Materials in Series by Virtual Parameter Methods 下载免费PDF全文
With the assumption that the constitutive relationship of every single cushioning layer is known in advance, this paper presents virtual parameter methods for predicting compressive responses of composite cushioning materials in series (i.e. multi‐layered cushioning materials). In the proposed methods, a derivative term is introduced to transform nonlinear algebraic equations for characterizing compressive behaviours of the composite cushioning materials into explicit differential equations under quasi‐static loadings. Introducing a first or second order derivate term is equivalent to introducing a virtual damping or virtual mass to the cushioning system. It is found that the solutions with the virtual parameter methods will diverge if the order of the introduced derivative term is higher than two, and the virtual parameter (i.e. the coefficient of the introduced derivative) must be larger than zero if first or second order derivative is used. The analytical results indicate that the terms associated with the virtual parameter in the predicted responses are a monotonically decreasing function of the virtual parameter if the latter is nonnegative. To trade off between prediction precision and computation convergence speed, an analytical process is developed for estimating the range of the virtual parameter. Then a scheme for jointly predicting the compressive response and optimizing the virtual parameter is proposed. For comparison, both simulations and quasi‐static compressive tests have been carried out on layered foam and corrugated paperboard structures, which correspond to materials without and with negative stiffness zone in the stress–strain curves, respectively. The results show that the predicted responses obtained using the proposed method match the experimental data very well. Moreover, unlike the Newton–Raphson iteration method, the proposed methods are able to capture the progressive buckling phenomenon for multi‐layered corrugated paperboard subjected to quasi‐static loading condition. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献