基于ANN-GA协同寻优的动态拉伸试样尺寸优化方法  

A method of geometry optimization for dynamic tensile specimen based on artificial neural network and genetic algorithm

作　　者：王清华 徐丰 郭伟国[1] WANG Qinghua;XU Feng;GUO Weiguo(School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,Shaanxi,China;School of Astronautics,Northwestern Polytechnical University,Xi’an 710072,Shaanxi,China;Qingdao Research Institute,Northwestern Polytechnical University,Qingdao 266200,Shandong,China)

机构地区：[1]西北工业大学航空学院,陕西西安710072 [2]西北工业大学航天学院,陕西西安710072 [3]西北工业大学青岛研究院,山东青岛266200

出　　处：《爆炸与冲击》2022年第1期107-119,共13页Explosion and Shock Waves

基　　金：国家自然科学基金(11702224,11872051)。

摘　　要：材料动态拉伸力学性能测试中,动态拉伸试样的几何尺寸对测试结果的准确性与有效性有着较大影响。为对动态拉伸试样的结构进行优化设计,以使其在动态拉伸过程中更好地满足一维应力与变形均匀等基本假设。首先,建立了量化的试样测量准确度指标,即应力平衡达到时间、变形均匀度、非轴向应力相对水平、过渡段相对变形。然后,对试样结构参数进行正交试验设计,通过数值模拟的方法得到了关于试样尺寸与测量准确度指标的正交试验数据库,并对正交试验数据库进行多目标正交试验矩阵分析,得到了试样结构参数对各测量准确度指标影响的主次顺序和规律。最后,以正交试验数据库为训练集,采用人工神经网络(artificial neural network,ANN)协同遗传算法(genetic algorithm,GA)的全局寻优方法对试样的结构尺寸进行优化设计,得到了试样的最优结构尺寸,并对最优尺寸的有效性进行了验证。结果表明,优化后的试样结构在材料动态拉伸力学性能测试精度上的表现明显得以提升。因此,采用ANN-GA协同优化的方法对动态拉伸试样的结构进行优化具有可行性和有效性。The split Hopkinson tensile bar is one of the most commonly used apparatuses to test the dynamic tensile mechanical properties of materials at the high strain rates from 10^(2) s^(−1) to 10^(3) s^(−1),in which the specimens with a dog-bone shape are usually used.The dimensions of the specimen used are critical to ensure the basic assumptions during dynamic tensile process,such as one-dimensional stress state and uniform deformation of the specimen etc.And whether these assumptions can be satisfied would affect the measurement accuracy of the dynamic tensile properties directly.So,it is urgent to study the influence of the specimen structural parameters on the stress and deformation states of the specimen during the dynamic tensile tests.At the same time,developing and establishing an effective method which can realize the global optimization of specimen structural parameters in the entire parameter space is crucial.In order to actualize the above research objectives,indicators which can quantify the measurement accuracy of the dynamic tensile tests were firstly proposed,namely the time required to reach the stress equilibrium,the deformation uniformity,the relative level of the non-axial stress,and the relative deformation of the transition zones.Orthogonal tests with 6 factors and 5 levels were then designed for the important structural parameters of the dog-bone shaped sheet tensile specimens.According to the rules of the orthogonal test design,25 dynamic tensile specimens with different structural dimensions were obtained.The commercial finite element software ABAQUS/Explicit was used to establish a finite element model of the split Hopkinson tensile bar,and dynamic tensile test simulations were performed on the dynamic tensile specimens obtained from the orthogonal test design.An orthogonal test dataset with the specimen structural parameters as the input and the measurement accuracy indicators as the output was then constructed.Multi-objective orthogonal test matrix analysis was carried out on the orthog

关 键 词：霍普金森杆 尺寸效应 试样设计 机器学习 遗传算法 

分 类 号：O383[理学—流体力学] TB302.3[理学—力学]