首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6篇
  完全免费   1篇
  力学   7篇
  2014年   1篇
  2010年   2篇
  2009年   1篇
  2007年   3篇
排序方式: 共有7条查询结果,搜索用时 62 毫秒
1
1.
Open celled metal foams fabricated through metal sintering are a new class of material that offers novel mechanical and acoustic properties. Previously, polymer foams have been widely used as a means of absorbing acoustic energy. However, the structural applications of these foams are limited. The metal sintering approach offers a cost- effective means for the mass-production of open-cell foams from a range of materials, including high-temperature steel alloys. In this first part of two-paper series, the mechanical properties of open-celled steel alloy (FeCrAlY) foams were characterized under uniaxial compression and shear loading. Compared to predictions from established models, a significant knockdown in material properties was observed. This knockdown was attributed to the presence of defects throughout the microstructure that result from the unique fabrication process. Further in situ tests were carried out in a SEM (scanning electronic microscope) in order to investigate the effects of defects on the properties of the foams. Typically, the onset of plastic yielding was observed to occur at defect locations within the microstructure. At lower relative densities, ligament bending dominates, with the deformation initializing at defects. At higher relative densities, an additional deformation mechanism associated with membrane elements was observed. In the follow-up of this paper, a finite element model will be constructed to quantify the effects of defects on the mechanical performance of the open-cell foam. The project supported by the US Office of Naval Research (N000140210117), the National Basic Research Program of China (2006CB601202), the National Natural Science Foundation of China (10328203, 10572111, 10632060), and the National 111 Project of China (B06024).  相似文献
2.
撞击载荷下泡沫铝夹层板的动力响应   总被引:1,自引:0,他引:1       下载免费PDF全文
应用泡沫金属子弹撞击加载的方式研究了固支方形夹层板和等质量实体板的动力响应,分别应用激光测速装置和位移传感器测量了泡沫子弹的撞击速度和后面板中心点的位移历史,给出了夹层板的变形与失效模式,研究了子弹冲量、面板厚度、泡沫芯层厚度及芯层密度对夹层板抗撞击性能的影响。结果表明,后面板中心点挠度最大,周边最小,整体变形为穹形,且伴有花瓣形的变形。参数研究表明,通过增加面板厚度或芯层厚度均能有效控制后面板的挠度,改善夹层板的能量吸收能力,结构响应对子弹冲量和芯层密度比较敏感。实验结果对多孔金属夹层结构的优化设计具有一定的参考价值。 更多还原  相似文献
3.
利用大型非线性有限元程序ABAQUS和LS-DYNA,对具有填充材料的金属格栅结构的冲击问题进行数值模拟.研究了不同的填充材料(金属泡沫和陶瓷)分别填充到不同的格栅构型(波纹型、蜂窝型和加强六边形)夹层板后,各类夹层板受到金属泡沫子弹和不锈钢子弹冲击时变形与能量吸收特性,探讨了夹层板上下面层板、支撑格栅及填充材料等各部分的吸能比率.研究结果表明,泡沫填充夹层板在缓冲吸能方面具有优势,陶瓷填充夹层板则在抵抗冲击穿透方面更具有优势,不同构型的夹层板,性能略有不同.  相似文献
4.
The metal sintering approach offers a cost- effective means for the mass-production of open-cell foams from a range of materials, including high-temperature steel alloys, which offer novel mechanical and acoustic properties. In a separate experimental study, the mechanical properties of open-celled steel alloy (FeCrAlY) foams have been characterized under uniaxial compression and shear loading. Compared to predictions from established models, a significant knockdown in material properties was observed. This knockdown was attributed to the presence of defects throughout the microstructure that result from the unique fabrication process. In the present paper, the microstructure of sintered FeCrAlY foams was modeled by using a finite element (FE) model. In particular, microstructural variations were introduced to a base lattice, and the effects on the strength and stiffness calculated. A range of defects identified under scanning electronic microscope (SEM) imaging were considered including broken ligaments, thickness variations, and pore blockages, which are the three primary imperfections observed in sintered foams. The corresponding levels of defect present in the material were subsequently input into the FE model, with the resulting predictions correlating well with experimental data. The project supported by the National Basic Research Program of China (2006CB601202), the National Natural Science Foundation of China (10328203, 10572111, 10632060), the National 111 Project of China (B06024), and the US Office of Naval Research (N000140210117).  相似文献
5.
The exact analytic solution of the pure bending beam of metallic foams is given. The effects of relative density of the material on stresses and deformation are revealed with the Triantafillou and Gibson constitutive law (TG model) taken as the analysis basis. Several examples for individual foams are discussed, showing the importance of compressibility of the cellular materials. One of the objects of this study is to generalize Hill’s solution for incompressible plasticity to the case of compressible plasticity, and a kinematics parameter is brought into the analysis so that the velocity field can be determined. The English text was polished by Yunming Chen.  相似文献
6.
将泡沫填充圆管的能量吸收视为泡沫与圆管两者之和,基于包含偏心率效应的直链塑性铰模型和Reddy等对Alexander模型的改进结果,对圆管的变形模式进行了更改,以此来反映管壁与金属泡沫之间的相互作用效应,导出了金属泡沫填充圆管的静、动态轴向平均压溃力的表达式.通过理论预测与实验的对比,发现理论预测偏低,但与实验曲线的趋势保持一致,比空管与金属泡沫的平均载荷之和略高一些.此外,泡沫填充圆管的平均压溃力随填充泡沫平台应力的增大而呈线性增加,与已有研究结果及实际情况一致,由此表明了模型的合理性.  相似文献
7.
针对通孔金属泡沫中的渗透率预测及现有理论模型的局限性,发展了一种新的全解析渗透率模型.该模型以立方体结构作为代表单元,采用基于追踪流体微团轨迹的分支算法解析求解代表单元内的流动迂曲度.渗透率的表达形式简单且不含任何拟合或经验参数,仅是孔隙率与平均孔径的函数.采用实验测量和文献数据对模型预测进行了验证.结果表明:提出的模型能够在较为宽广的孔隙率(0.55~0.98)和孔密度(5~100 PPI)范围内预测孔通孔金属泡沫的渗透率;采用分支算法得到的流动迂曲度能够较好地描述流体在通孔金属泡沫中的流动特征;采用开孔率修正的解析模型亦能对半开孔泡沫材料的渗透率提供良好预测.  相似文献
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号