线性增加冲击荷载作用下圆盘试样的动态应力平衡

来源期刊:中国有色金属学报2014年第1期

论文作者:张 盛 李新文 杨向浩

文章页码:75 - 82

关键词:分离霍普金森压杆;应力平衡;圆盘试样;加载直径;动态断裂韧度

Key words:split Hopkinson pressure bar; stress equilibrium;disc specimen;loading diameter;dynamic fracture toughness

摘    要:为了考察含有预制裂缝的圆盘试样在SHPB系统上受线性增加冲击荷载作用过程中的应力平衡性,采用ANASYS有限元软件对圆盘试样的动态冲击进行数值模拟,获得圆盘的动态应力时间历程,对圆盘试样两个加载平台及加载直径韧带上节点的应力进行定量对比分析,提出确定动态应力平衡性判定的方法。结果表明:圆盘靠近入射端接触平台面上点的应力一致,而靠近透射端接触平台不同点的应力差异却非常大,尽管裂纹尖端附近节点的拉应力值较为接近,但在冲击载荷作用过程中,圆盘加载直径韧带上对称部分的节点动态应力始终无法达到平衡,较小的应力差异就能引起应力平衡度量值较为严重的振荡。这有助于正确认识岩石动态冲击破坏过程和提出准确测试岩石动态断裂韧度的方法。

Abstract: In order to analyze the stress balance of the prefabricated crack disc specimen impacted under linear increase impact loads in split Hopkinson pressure bar (SHPB) impact system, the dynamic numerical simulation were performed by ANASYS finite element software. The whole dynamic stress history of the disc specimen was got, and the node dynamic stress of two loading platforms and the loading diameter ligament of the disc specimen were compared and analyzed quantitatively. The method to determine dynamic stress equilibrium was introduced, too. The results show that the nodes stress of the platform surface near the incidence end are consistent, while the one near the transmission end are obviously different. Although the node stress near crack tip is relatively close, the dynamic stress of the disc loading diameter ligament on symmetry part are always unable to keep balance, and smaller difference can cause serious stress oscillation. It is helpful to understand the rock dynamic failure and propose a correct test method to determine the dynamic fracture toughness.

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