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颗粒增强镁基复合材料微区应力场的仿真模拟*
李晓军 柴东朗 郗雨林 曹利强
(西安交通大学金属材料强度国家重点实验室,陕西 西安,710049) 摘 要 本文采用借助有限元软件 FEPG 仿真模拟了 SiC 颗粒增强镁基复合材料中实际形状的增强体周围的微区应力场. 结果表 明,不同形状的增强体颗粒附近的微区应力场差异很大,个别颗粒会在低应力下失效.当增强体的体积分数较少时,每个增强体 的微区应力场受其它增强体影响不大,近似给出单个增强体的形状就可以仿真模拟出增强体附近的微区应力场.利用粉末冶金法 制备了颗粒增强镁基复合材料,观察其拉伸断口,并利用有限元方法进行仿真模拟,据此进行了增强体颗粒的失效分析. 关键词 镁基复合材料 有限元 仿真模拟
Analog Simulation of Local Stress Field on Magnesium Matrix Composites Reinforced with Particles
Li Xiaojun , Chai Donglang
(State Key Laboratory for Mechanical Behavior of Materials in Xi'an Jiaotong University, Xi'an, 710049, China)
Correspondent: Li Xiaojun, Candidate for master's degree, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, P.R. China, Tel: 029-2674487,E-mail:cdl@mail.xjtu.edu.cn ABSTRACT The local stress field of actual particles in magnesium matrix composites reinforced with SiC particles was simulated by using the finite element software FEPG. The result suggests that the local stress fields of particles with different shapes have great difference and some particles will fail under lower stress. If the volume fraction of particles is less, other particles have little influence on the local stress field of a certain particle. Therefore, the local stress field of a particle can be simulated with given shape. Magnesium matrix composites reinforced with SiC particles were prepared by powder metallurgy. Fracture analysis was performed and was compared with the particle failure analysis carried out by finite element method. KEY WORDS magnesium matrix composite, finite element method, analog simulation
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前言
颗粒增强镁基复合材料具有比同类普通合金更高 的比刚度,比强度,热稳定性,耐磨性以及低的热膨 胀系数,生产成本低,成为新材料研发的一个热点 [1-5].然而,作为一种多组分的材料,其性能不稳 定,材料失效也比普通材料复杂得多,不能通过简单 的力学计算得到,国内外的许多学者采用有限元方法 对此进行了研究[6-8].但目前的研究大多是基于某种 理想化的模型,尚未见到有人模拟真实颗粒周围的应 力场并据此进行失效分析.本文采用有限元方法仿真 模拟了 SiC 颗粒增强镁基复合材料中实际形状的增强 体周围的应力场,并和实验结果进行了对比.
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建立有限元计算的几何模型
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模型图
市售的碳化硅颗粒是具有尖角及棱角的磨料级 角状碳化硅,这种常用的碳化硅颗粒实际上并非为等

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