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31.
32.
充气压力容器在超高速撞击下的典型损伤包括穿孔及其边缘的裂纹失稳破坏,会导致气体泄漏或爆炸,内压对容器前壁损伤的影响仍不明确。以不同内压的球形铝合金充气压力容器为研究对象,开展了球形铝合金弹丸超高速撞击实验和数值模拟计算,分析了内充气体压强对前壁穿孔形貌特征、穿孔直径、孔边环向应力等的影响规律和影响机理,讨论了气体冲击波的传播行为及影响前壁穿孔边缘裂纹失稳破坏的机制。结果表明:前壁穿孔边缘内翻边形貌与内压相关,内压越高,弯折程度越轻;穿孔直径与内充气体压强正相关,但气体对孔径的影响远小于容器壁厚及撞击速度的影响;穿孔边缘使裂纹失稳破坏的环向拉应力不仅受到后壁反射冲击波的影响,也与容器壁内应力波的传播有关,与内压成正比。 相似文献
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34.
The flow structure in a flat plate integrated collector storage device, with recirculation of the storage water, is studied experimentally and theoretically. To facilitate flow visualization, an experimental device was constructed by transparent material (Plexiglas). Flow velocities and fluctuations are measured, using a LDV system. A three-dimensional CFD-model was developed using the FLUENT code. The standard k–ω model is selected as the most appropriate. The model is validated, with good agreement, against experimental measurements. Furthermore, copper tubes, in the form of embedded heat exchanger, are placed inside the device and another similar 3D model was developed. The model was used to examine the behavior of the system, when the service water enters the heat exchanger, thus being indirectly heated by the stored hot water. It is shown that the outlet temperature of the service water is enough higher, when recirculation occurs. 相似文献
35.
Zhang Shu-hui Liang Guo-zheng Zhang Wei Zeng Jin-fang 《Mechanics of Composite Materials》2006,42(6):507-512
The surface of aramid fibers was modified with a polymer coating — a surface treatment reagent containing epoxy resin. The
resulting fibers were examined by using NOL tests, hydroburst tests, and the scanning electron microscopy. The modified fibers
had a rougher surface than the untreated ones. The interlaminar shear strength of an aramid-fiber-reinforced epoxy composite
was highest when the concentration of polymer coating system was 5%. The translation of fiber strength in an aramid/epoxy
composite vessel was improved by 8%. The mechanism of the surface treatment of fibers in improving the mechanical properties
of aramid/epoxy composites is discussed.
Russian translation publeshed in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 6, pp. 729–738, November–December, 2006. 相似文献
36.
A zero-curvature criterion is proposed to determine the practical collapse load. Six tests have been carried out on spherical pressure vessels with cylindrical nozzle. Results of these tests and other experimental data quoted from different references are discussed in order to compare the new criterion with various previously proposed criteria. It is concluded that: (1) the zero-curvature point is a characteristic point of the experimental curve and that the new criterion is an objective criterion without any artificial coefficient. (2) the deviation of the collapse load estimated by the new criterion is smaller than that estimated by other criteria.Supported by the Chinese National Foundation of Natural Science. 相似文献
37.
朱锡雄 《宁波大学学报(理工版)》1988,(1)
本文结合我国核动力反应堆的实例,首先介绍了设计规范中采用的断裂分析图的评定方法,然后着重讨论一种新的断裂力学的评定方法。结合对容器材料断裂韧性的实验测定,给出了计算结果,绘制了全寿期的安全运行工况图,并对两种方法的结果作了比较讨论。 相似文献
38.
本文利用解析方法,建立了球形容器角变形的一些几何关系式与局部应力的分析表达式;求得了一个简明而且实用的应力集中系数公式,表明应力集中不仅依赖于角变形量,而且随径厚比的平方根的增加而增加。 相似文献
39.
在外杜瓦系统上设置了爆破片装置,借助大型有限元分析程序ANSYS,对爆破片和托架进行了分析,所得结果与实验结果良好吻合,为同类装置的过压泄放提供了有益的参考。 相似文献
40.
Chao Deng Fengfu Li May Griffith Marc Ruel Erik J Suuronen 《Macromolecular Symposia》2010,297(1):138-146
Summary: Vascular diseases are the leading cause of morbidity and mortality in the western world. Autologous vessels remain the standard for coronary grafting and peripheral bypass surgery; however, their availability in patients can be limited. Therapeutic angiogenesis using growth factors, genes, or progenitor cells has been given considerable scientific attention over the last decade, but has not yet provided a definitive clinical benefit. Biomaterials could be developed to protect protein, DNA and cells against hostile conditions. Chitosan, a natural polymer of glucosamine and N-acetyl glucosamine, has been widely studied in tissue engineering due to its biocompatibility, biodegradability, and muco-adhesive and antimicrobial properties. Notably, the application of chitosan has been gaining attention in the vascular field due to its structural similarity to glycosaminoglycans, which are components of a tissue's extracellular matrix. In this review, chitosan-based materials, and their use in tissue engineered blood vessels, and as protein, gene and cell vectors for angiogenic therapy are discussed. 相似文献