应力不均匀性对混凝土材料动态实验结果的影响
THE EFFECT OF STRESS HETEROGENEOUS ON TEST DATA OF CONCRETE USING SHPB
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摘要: 利用直径75mm 的SHPB(Split Hopkinson Pressure Bar)装置对混凝土做动态冲击实验,然后利用自编程序对数据进行分析。该程序可以直观地显示试件两端面的应力不均匀水平,在实验过程中进行应力均匀性检查,从而调整整形器,改变波形,提高应力的均匀性。由于不能消除这种不均匀性,因此三波法与两波法得到的应力-应变关系不一致,造成实验数据处理结果不确定。该文采用经验和理论相结合的三波校核法得到相对可信的唯一性应力-应变曲线。Abstract: The dynamic response of concrete is investigated using a 75-mm-diameter Split Hopkinson Pressure Bar (SHPB) test. The data of the experiment are analyzed through our developed program. The program can display the stresses on the two end surfaces of the specimen. Thusly we can examine the difference of the stresses, then, adjust the pulse shaper in order to change the shape of the incident wave and reduce the difference. But the difference does exist, causing the different stress-strain curves obtained from two wave method or three wave method. There are a numbers of critical issues pertaining to the method. In this paper, combining theory and experience, we get a comparatively creditable stress-strain curve using Three Waves Checking Method.