基于内聚力失效微观单胞模型的树脂砂拉伸性能的数值研究  

Numerical Study on Tensile Behavior of Resin Sand Based on Micro-Scale Unit Cell Model Involving Cohesive Failure Mechanism

作　　者：冀运东[1,2] 郑凯东 王遥 钟飞升 曹东风 JI Yun-dong;ZHENG Kai-dong;WANG Yao;ZHONG Fei-sheng;CAO Dong-feng(School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China;State Key Laboratory of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei, China;Zhangwu Lianxin Foundry Material Co., Ltd., Fuxin 123200, Liaoning, China)

机构地区：[1]武汉理工大学材料科学与工程学院,湖北武汉430070 [2]武汉理工大学材料复合新技术国家重点实验室,湖北武汉430070 [3]彰武县联信铸造硅砂有限公司,辽宁阜新123200

出　　处：《铸造》2019年第4期364-371,共8页Foundry

基　　金：中国博士后科学基金(2018M632933);航空自然科学基金(20152365002)

摘　　要：原砂粒度及分布、树脂膜厚度和空隙分布构成树脂砂微细观结构特征决定着树脂砂宏观力学行为。针对原砂/树脂间弱界面脱粘与树脂基体失效这两种失效模式,构建了基于断裂力学微细观单胞模型,研究了树脂砂微观结构的失效/断裂演化机制,以及3类微观结构(即:树脂包覆层厚度,砂粒直径和粒径级配)对于树脂砂宏观力学行为的影响。计算结果表明,所构建的数值模型能够考虑裂纹尖端的应力集中以及砂粒弧面的几何效应,具备描述在拉伸载荷下树脂砂界面损伤/界面裂纹扩展以及树脂包覆层的内聚失效行为的能力,为树脂砂失效断裂机理的研究提供了一种更加直接有效的工具;微细观结构对树脂砂拉伸力学性能影响研究表明,树脂包覆层厚度、砂粒直径和粒径级配对树脂砂的拉伸强度、比强度、拉伸刚度以及极限拉伸变形量有着不同程度的影响。The micro-structure characteristics of resin sand, such as sand grain size, size distribution, resin film thickness and void distribution, determines the macroscopic mechanical behavior of resin sand. In order to describe the two failure modes, i.e., interface debonding between sand and resin as well as resin matrix failure, a micro-scale unit cell model based on fracture mechanism was proposed. The micro-scale structure failure,damage evolution and the effect of 3 kinds of micro-structure(thickness of resin film, sand grain size, and size distribution) on macro-scale behavior of resin sand were studied. The calculation results showed that the proposed model could be used to describe the stress concentration of crack tip and the geometric effect of sand particles with cambered surface, and had the ability to capture interface debonding and resin matrix failure, which would provide a more effective tool for the research of micro-scale failure mechanisms further.The study on the effect of microstructure on the tensile mechanical properties of resin sand, showed that the thickness of resin film, sand grain size and size distribution had impact of different degrees on tensile strength,specific strength, tensile stiffness and ultimate tensile deformation of the resin sand.

关 键 词：树脂砂 微细观结构 单胞模型 断裂机理 

分 类 号：TG221[金属学及工艺—铸造]