作者：刘晓坤, 蔡力勋, 陈辉

作者单位：西南交通大学力学与工程学院 应用力学与结构安全四川省重点实验室, 四川 成都 610031

关键词：压入设备;应力应变关系;加载曲率;有限元仿真

摘要：

采用自主研发的便携式压入设备,对材料平滑表面进行单调压入试验获得载荷深度曲线,进而获得材料的单轴应力应变关系曲线。在等向强化、各向同性、单调加载条件下,基于能量原理和有限元分析提出应用双锥无卸载的压入载荷深度曲线预测具有Hollomon律的材料应力应变关系半解析新公式。在有限元验证方面,根据不同材料的Hollomon律应力应变作为有限元本构关系条件获得的载荷深度分析结果与压入载荷深度关系吻合较好。在试验方面,通过压入载荷深度曲线得到加载曲率,然后利用半解析新公式得到的材料单轴应力应变关系与单轴拉伸试验结果进行比较,结果表明新方法获取的材料应力应变关系和单轴拉伸试验结果有较好的一致性。

A new conical indentation method for obtaining stress-strain relation of materials

LIU Xiaokun, CAI Lixun, CHEN Hui

Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China

Abstract: A self-developed portable indentation device is to conduct monotonic indentation test on the smooth surfaces of materials to obtain load-displacement curves and then uniaxial stress-strain curves. Under hardening, isotropic and monotonic loading conditions, a semi-analytical formulawith Hollomon's law by which the stress-strain relation of materials is predicted through the dipyramidal offload indentation load-depth curve is proposed according to the effective energy theory and finite element analysis (FEA). In FEA verification, the analytical load-depth results are gained by using the Hollomon's law of different materials as the constitutive relation of the finite element. In test, loading curvature is acquired from the indentation load-depth curve, and by comparison it is observed that the uniaxial stress-strain relation obtained through the new formula is identical with the results of the uniaxial tension experiment.

Keywords: indentation device;stress-strain relation;loading curvature;FEA

2016, 42(4): 5-8,14  收稿日期: 2015-12-03;收到修改稿日期: 2016-01-09

基金项目: 国家自然科学基金(11472228)

作者简介: 刘晓坤(1991-),男,河南商丘市人,硕士研究生,专业方向为材料力学行为与测试技术。

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