Forming Limit Analyses of Cold Rolled IF Steel Sheet Using Differential Work Hardening Model
Forming Limit Analyses of Cold Rolled IF Steel Sheet Using Differential Work Hardening Model
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利用微分加工硬化模型分析冷轧IF钢板的成形极限
DOI：
10.1016/j.proeng.2014.10.105
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Tomoyuki Hakoyama・Toshihiko Kuwabara
中科院分区：
文献类型：
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作者：
吾郷由希夫;Michael Condro;早田敦子;河内琢也;橋本 均;James Waschek.;Tomoyuki Hakoyama・Toshihiko Kuwabara
采用伺服多轴管膨胀试验机对冷轧IF钢板在初始屈服至断裂应变范围内的多轴塑性变形行为进行了试验研究。该试验机能够利用电气闭环伺服控制系统对轴向力和内部压力施加任意主应力或应变路径。以厚度为0.7 mm的冷轧无间隙钢板为材料，采用辊弯和激光焊接工艺制备了内径为44.6 mm的管状试样。对管状试样施加应力空间第一象限的多条线性应力路径，测量成形极限曲线和成形极限应力曲线，以及塑性工作的轮廓和塑性应变率的方向。结果表明，随着塑性功的增加，被测工件轮廓的形状发生了变化。通过改变材料参数和Yld2000-2d屈服函数指数（Barlat et al., 2003）作为等效塑性应变的函数，可以近似地观察到加工硬化行为的差异。采用Marciniak-Kuczyński-type方法和微分加工硬化模型计算了成形极限曲线和成形极限应力曲线。计算结果与实测结果基本吻合。
A servo-controlled multiaxial tube expansion testing machine was used to measure the multiaxial plastic deformation behavior of a cold rolled IF steel sheet for a range of strain from initial yield to fracture. The testing machine is capable of applying arbitrary principal stress or strain paths to a tubular specimen using an electrical, closed-loop servo-control system for an axial force and an internal pressure. Tubular specimens with an inner diameter of 44.6 mm were fabricated from a cold rolled interstitial-free steel sheet with a thickness of 0.7 mm by roller bending and laser welding. Many linear stress paths in the first quadrant of stress space were applied to the tubular specimens to measure the forming limit curve and forming limit stress curve of the as-received sheet sample, in addition to the contours of plastic work and the directions of the plastic strain rates. It was found that the shapes of the measured work contours changed with increasing plastic work. The observed differential work hardening behavior was approximated by changing the material parameters and the exponent of the Yld2000-2d yield function (Barlat et al., 2003) as a function of the equivalent plastic strain. The forming limit curve and forming limit stress curve were calculated using the Marciniak-Kuczyński-type approach and the differential work hardening model. The calculated results were in fair agreement with the measurement.