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Robb M. Kulin Fengchun Jiang Kenneth S. Vecchio 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(6):39-44
Whether due to a sporting accident, high-speed impact, fall, or other catastrophic event, the majority of clinical bone fractures
occur under dynamic loading conditions. However, although extensive research has been performed on the quasi-static fracture
and mechanical behavior of bone to date, few high-quality studies on the fracture behavior of bone at high strain rates have
been performed. Therefore, many questions remain regarding the material behavior, including not only the loading-rate-dependent
response of bone, but also how this response varies with age. In this study, tests were performed on equine femoral bone taken
post-mortem from donors 6 months to 28 years of age. Quasi-static and dynamic tests were performed to determine the fracture
toughness and compressive mechanical behavior as a function of age at varying loading rates. Fracture paths were then analyzed
using scanning confocal and scanning-electron microscopy techniques to assess the role of various microstructural features
on toughening mechanisms. 相似文献
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D. V. Zaytsev N. V. Selezneva S. S. Grigoriev P. E. Panfilov 《Protection of Metals and Physical Chemistry of Surfaces》2013,49(5):517-520
The influence of liquid on the mechanical properties of human dentin under uniaxial compression is studied in this work. It has been shown that the storage of samples for 24 h in water, acetone, and glycerin does not lead to a change in the microstructure or to qualitative changes in the mechanical behavior of dentin, which continues to be highly elastic; capable of considerable plastic deformation; and a strong, hard tissue. 相似文献
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Elastic modulus and hardness of cortical and trabecular bovine bone measured by nanoindentation 总被引:1,自引:0,他引:1
《中国有色金属学会会刊》2006,16(B02):744-748
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本实验选取与人体骨组织生物力学性能相接近的牛长骨为研究对象,用不同种类的砂轮进行磨削,研究骨组织磨削特性。实验结果表明:长骨骨干不同方向的磨削力不同,截面磨削力最大,侧面磨削力次之,表面磨削力最小;骨组织磨削力随磨削深度和工件速度的增大而增大,随砂轮速度的增大而减小;采用金刚石砂轮磨削骨组织的磨削力比采用氧化铝砂轮磨削时的磨削力要小得多;骨组织的磨削力比在3~5之间。通过对骨组织磨削特性的研究,为磨削技术在骨外科手术中的应用提供一定的参考。 相似文献
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针对精冲成形齿形件时的齿顶塌角问题,首先分析了齿形零件的几何特征及精冲成形特点,并分析了这些特征与齿形零件精冲时齿顶塌角的关系;将精冲变形区分为2个核心变形区和2个变形影响区,对核心变形区Ⅰ精冲塌角的形成过程进行了分析。然后,通过有限元模拟软件Deform-3D,找出齿顶塌角处材料在成形过程中的流动规律。结果表明:齿顶处A面轮廓附近的材料沿齿顶径向运动,一部分材料流向齿顶外侧;齿廓B、C侧附近的材料沿其轮廓线所指向的齿顶方向流动。再次,全面分析了影响精冲齿顶塌角大小的各种因素,找出压边力和反顶力对塌角大小的影响规律,得出反顶力比压边力对控制塌角的效果更显著。最后,提出了在齿形零件精冲成形过程中减小或消除齿顶塌角的具体措施对策。 相似文献
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《中国铸造》2019,(6)
Foamed zinc was prepared by infiltration casting process. The mechanical properties and corrosion resistance of the samples were studied, and the feasibility of the foamed zinc as a bone implant material was discussed. All the compression stress-strain curves of open-cell zinc foams with various cell size(1-4 mm) and porosity(55%-67%) show three stages: elastic stage, plastic stage, and densification stage. The compression strength increases with decreasing density. The smooth stress-strain response indicates a progressively deformation of open-cell zinc foam. In addition, the cell wall or edge bending and fracture are the dominated mechanisms for failure of open cell zinc foam. The immersion test for determining the corrosion rate of open cell zinc foam was conducted in simulated body fluid. It was found that zinc foam with a small cell size and high porosity showed a higher corrosion rate. In addition, open-cell zinc foams can effectively induce Ca-P deposition in immersion tests, showing good bioactivity. Therefore, the open cell zinc foam prepared in this experiment has a good potential application as a human bone substitute material. 相似文献
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利用微合金化法设计了引线框架用Cu-Fe-P合金的成分(Cu-2.5Fe-0.12Zn-0.03P-0.05Mg-0.05Cr-0.05RE),采用金相显微镜(OM)和高分辨电子显微镜(HRTEM)研究了合金的微观组织,测定了合金的抗拉强度、伸长率及电导率等性能.试验结果表明,在其他试验条件相同的情况下,冷轧后的合金板材经550 ℃×4 h时效后处于过时效状态,球形的析出相γ-Fe粗化,尺寸在50~100 nm的范围,合金的强度为482 MPa,显微硬度HV为161,电导率为39.7 MS/m;经450 ℃×4 h时效后处于欠时效状态,呈球形的γ-Fe相尺寸在20 nm以下,抗拉强度为417 MPa,显微硬度HV为139,电导率是30.4 MS/m;经550 ℃×2 h 450 ℃×2 h时效后处于峰值时效状态,球形的γ-Fe相尺寸在20~50 nm的范围,此时合金的抗拉强度为510 MPa,显微硬度HV为168,导电率为40.6 MS/m. 相似文献
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利用显微硬度、TEM、HREM等测试方法对Al-Er-Zr合金的时效析出过程及析出相Al3(Er1-xZrx)的粗化行为进行研究。结果表明:二元合金Al-0.04Er在375℃时效5 min后出现硬度峰(约为40.3HV),随后迅速下降出现过时效;添加Zr能够显著提高其热稳定性,三元Al-Er-Zr合金中过时效现象显著滞后于Al-Er二元合金。在三元合金Al-Er-Zr中,随着Zr含量的增加,合金在长时间时效后,由于Er、Zr的协同析出而出现第二个更高的时效峰值,约为53.5HV,明显高于Al-Er二元合金的硬度。Al3(Er1-xZrx)粒子在高温粗化过程中逐渐长大,其平均直径d与退火时间t的关系符合LSW理论中的关系式。 相似文献
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Cleaning and polishing of teeth is carried out to improve the aesthetic looks and also to minimise food particles sticking to the surface of the tooth. Any procedure done on the tooth tends to change the gloss or shine of the tooth. Currently, there is no instrument available to measure or quantify the change in the gloss under clinical conditions on the surface of a complex shape such as a live tooth. This paper describes the application of a portable glossmeter that can be used by the end user of oral hygiene products to evaluate the efficacy of the product under the household or clinical conditions. Also, the patient himself can evaluate results of any procedure carried out by the dental surgeon. It should be noted that other industrial applications with complex shapes requiring evaluation of a surface finish are also likely to find this technique of value. 相似文献
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Cu-Zr-Te合金的时效特性研究 总被引:1,自引:0,他引:1
在Cu-Zr-Cr合金中采用Te元素代替合金中的Cr元素,从而避免了Cr6 可能产生的危害。分别对两种状态的Cu-Zr-Te合金进行时效工艺的研究,并采用扫描电镜(SEM)和能谱(EDM)分析了析出相的形貌和成分,以及时效工艺对合金材料的电性能及力学性能的影响。固溶 冷变形处理后的合金材料,在500℃下保温60min时效处理能使合金的综合性能优异。 相似文献