摘要
基于预测水泥及其水化物体积性能的简化物理模型Wittmann模型,结合分子动力学研究方法,构建水化硅酸钙(C-S-H)凝胶模型用来模拟纳米压痕实验.在弛豫阶段使用高温淬火方法将模型转变为无定形态,并测定模型高温淬火前后的径向分布函数,确定了无定形态下的水化硅酸钙(C-S-H)压痕模型,计算得出荷载深度曲线(P-h曲线).考虑到高温淬火对模型内粒子热力学运动的影响以及带来的位错效应,分别采用OliverPharr方法与Cheng-Cheng方法对荷载深度曲线的卸载段进行分析处理.其中Oliver-Pharr方法计算得到硬度H为0.92 GPa,折合模量Er为29.56 GPa;Cheng-Cheng方法计算得到折合模量Er为(34.92±7.57) GPa.与文献结果及标准试块实验结果进行对照,探究两种计算方法的合理性及适用范围,并提出研究展望.
Based on the Wittmann model, which is a simplified physical model to predict the volume performance of cement and its hydration, and combined with the molecular dynamics method, a calcium silicate hydrate(C-S-H) gel model was constructed to simulate the nano indentation test. In the relaxation stage, the model was transformed into an amorphous form by high-temperature quenching method, and the radial distribution function before and after high-temperature quenching was measured to determine the indentation model of calcium silicate hydrate(C-S-H) of amorphous form, leading to the attainment of the load depth curve(P-h curve). In consideration of the dislocation effect caused by high temperature quenching which has an influence on the thermodynamic motion of particles in the model, the unloading section of the load depth curve was analyzed and treated by both the Oliver-Pharr method and the Cheng-Cheng method. The hardness H calculated by Oliver-Pharr method was 0.92 GPa and the reduced modulus Er was 29.56 GPa. The reduced modulus Er calculated by Cheng-Cheng method is(34.92±7.57) GPa. The rationality and application range of the two calculation methods were explored by comparing the results with those in the literature as well as from the experiments on standard blocks. Finally some research prospects were given.
作者
张子星
杨海霞
邵婷悦
ZHANG Zixing;YANG Haixia;SHAO Tingyue(College of Mechanics and Meterials,Hohai University,Nanjing 211100,Jiangsu,China)
出处
《力学季刊》
CAS
CSCD
北大核心
2021年第4期731-742,共12页
Chinese Quarterly of Mechanics
基金
国家自然科学基金(U1965207)。
