【摘要】 在金属切削过程中,切削区域会产生较大的应力、应变及应变率,远高于传统机械测试(包括Split–Hopkinson压杆测试)所能达到的应变率。因此,提出了一种新的方法来辨识金属材料本构参数,该方法基于切削过程高分辨率原位成像和数字图像相关技术(DIC),再结合解析算法优化,最终辨识出材料本构模型最优参数,此方法尤为适用于辨识应变和应变率较大情况下的本构参数。采用原位成像技术对45钢(美标AISI 1045)进行正交车削试验,通过DIC技术分析获得第1剪切变形区的应变和应变率场,然后基于本构方程计算应力场,获得第1剪切变形区剪切平面中的应力积分,并与投射到剪切平面上的测力仪测量获得的切削力的分量相匹配,通过求解序列优化问题,得出最优本构参数。最后,将获得的材料本构参数输入到切削仿真模型中,将仿真结果与试验结果进行对比,验证此方法的可行性和有效性。更多还原

【Abstract】 The cutting process produces large stress, strain and strain rate, which are much higher than those in traditional mechanical tests, including Split-Hopkinson pressure bar test. Therefore, a new method is proposed to identify the constitutive parameters of metal materials. This method is based on high-resolution in-situ imaging and digital image correlation technique(DIC), combined with analytical algorithm optimization, the optimal parameters of materials constitutive model have been identified. It is especially suitable for identifying constitutive parameters in the case of large strain and strain rate. In-situ imaging technique is used to perform orthogonal turning experiments on 45 steel(AISI 1045),and the strain and strain rate fields in the primary shear zone(PSZ) are obtained using DIC technique. Then, the stress field is calculated based on the constitutive equation. Stress integrations in the PSZ shear plane are obtained and matched with the component of the cutting force measured by the dynamometer projected onto the shear plane, and the optimal constitutive parameter is identified by performing the optimization of the solution. Finally, the feasibility and effectiveness of the proposed method are verified by comparing the results of finite element simulation using the identified constitutive parameters with the experimental results.更多还原