SiC/SiC陶瓷基复合材料面内剪切模量测试方法  

In-plane shear mechanical properties of SiC/SiC ceramic matrix composites Study of test methods

作　　者：王海润 郝自清 刘刘 王雅娜 WANG Hairun;HAO Ziqing;LIU Liu;WANG Yana(School of Astronautics,Beijing Institute of Technology,Beijing 100081,China;Division of Ceramic Matrix Composites,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]北京理工大学宇航学院,北京100081 [2]中国航发北京航空材料研究院陶瓷基复合材料研究所,北京100095

出　　处：《航空材料学报》2025年第2期91-101,共11页Journal of Aeronautical Materials

基　　金：稳定支持项目(KZ0C230599)。

摘　　要：陶瓷基复合材料(ceramic matrix composites,CMC)作为一种优异的高温结构材料,在航空发动机领域得到了广泛应用。目前,依据GJB 10311—2021的双切口面内剪切实验方法存在明显局限性:切口位置处的应力集中效应导致标距区平均剪切应力计算结果偏高,使得面内剪切模量测试结果与V形缺口剪切实验偏差可达30%。为此,本工作将数字图像相关方法(DIC)与双切口剪切实验相结合,开发一种面内剪切力学性能测试的新方法。为消除切口处应力集中的影响,提出采用有限元模型修正技术(finite element model updating,FEMU),利用DIC实测标距区内面内平均剪切应变与数值计算应变之间的方差构造目标函数,迭代获得材料的面内剪切模量。为便于工程应用,通过优化试样切口深度,实现单次实验即可获得材料的面内剪切模量和面内剪切强度,并采用SiC/SiC正交层合陶瓷基复合材料进一步验证了该实验方法的可行性和测试结果的可靠性。结果表明:该实验方法可同时准确测定陶瓷基复合材料的面内剪切模量和强度,测试结果与V形缺口实验结果偏差小于5%。相较V形缺口剪切实验,该方法实验工装和试样尺寸更小,更适用于高温面内剪切实验。SiC/SiC复合材料面内剪切应力-应变存在典型的屈服点,且屈服后剪切行为表现出典型的线性应变强化特征。Ceramic matrix composites(CMCs),as outstanding high-temperature structural materials,have found extensive application in aero engines.Consequently,it is crucial to conduct research on high-temperature mechanical property test methods and ascertain these properties to broaden CMC applications in the aerospace sector.The double-in-plane shear test scheme recommended by the national military standard GJB 10311-2021 often results in high calculated average shear stress in the gauge area due to stress concentration at the incision,leading to significant deviations between in-plane shear modulus test results and those of the V-notch shear test.To address this,a novel in-plane shear mechanical property test method has been developed by integrating the digital image correlation method(DIC)with the double-incision shear test.Compared to the V-notch shear test,this method boasts a smaller test fixture and specimen size,making it more suitable for high-temperature in-plane shear testing.To mitigate the impact of stress concentration at the incision,finite element model updating(FEMU)is proposed,constructing an objective function based on the variance between the average in-plane shear strain and numerically calculated strain in the DICmeasured gauge area.This allows for iterative determination of the material’s in-plane shear modulus.For engineering application convenience,the material’s in-plane shear modulus and strength can be obtained by varying the specimen’s incision depth during testing.The feasibility of this test method and the reliability of its results are further validated using SiC/SiC orthogonal laminated ceramic matrix composites.Results indicate that the proposed experimental method can simultaneously determine the in-plane shear modulus and strength of CMCs.The SiC/SiC ceramic matrix composites exhibit typical yield points in their in-plane shear stressstrain behavior,with post-yield shear behavior characterized by linear strain strengthening.

关 键 词：陶瓷基复合材料 双切口剪切实验方法 数字图像相关方法 有限元模型修正 面内剪切模量 

分 类 号：V250.2[一般工业技术—材料科学与工程]