United States Steel Corporation, 5850 New King Ct., Troy, MI 48098, USA.
Traffic Inj Prev. 2013;14 Suppl:S23-9. doi: 10.1080/15389588.2013.790537.
Due to the rolling manufacturing process, most advanced high-strength steels (AHSS) demonstrate in-plane anisotropic material behavior. This study investigates the effects of material orientation on the axial crush behavior and fracture of AHSS with axial crush tests and computer simulations.
Crush simulation models considering material anisotropy and damage evolution were developed in LS-DYNA based on the drop-tower crush test results and coupon characterization test data for DP780 steel. The modified Mohr-Coulomb (MMC) isotropic fracture model was employed in the crush simulation models for fracture prediction.
The 12-sided components fabricated in the transverse (T) direction of the sheet exhibited slightly higher crush loads and reduced crush distances compared to those in the longitudinal (L) direction. The crush behavior in each direction was generally proportional to ultimate tensile strength. All of the materials investigated in this study showed some cracking in the crush tests for both component orientations, but only DP780 showed significant anisotropy in fracture behavior with more cracking for the T direction compared to the L direction. Overall, the amount of cracking observed in the tests had little or no significant effect on the axial crush performance. The MMC fracture loci in both the L and T directions were determined using a reverse engineering approach, and the stress-strain curves beyond the uniform elongation point were extended using an optimization method. Both material models MAT103 and MAT224 predicted the crush and fracture behavior with reasonably good accuracy.
The predicted fracture mode and force-displacement curves agreed well with the test data for both the L and T directions in axial crush tests of the 12-sided components. The simple isotropic material model MAT224 is adequate for crush simulations to predict material orientation effects on AHSS component crush performance and fracture behavior.
由于轧制制造工艺，大多数先进高强度钢（AHSS）表现出面内各向异性的材料行为。本研究通过轴向压缩试验和计算机模拟研究了材料方向对 AHSS 的轴向压缩行为和断裂的影响。
基于落锤压缩试验结果和 DP780 钢的试件特性试验数据，在 LS-DYNA 中开发了考虑材料各向异性和损伤演化的压缩模拟模型。在压缩模拟模型中采用修正的莫尔-库仑（MMC）各向同性断裂模型进行断裂预测。
与纵向（L）方向相比，板材横向（T）方向制造的 12 边形构件表现出稍高的压缩载荷和减小的压缩距离。各向压缩行为通常与极限拉伸强度成正比。在所研究的所有材料中，在两种构件方向的压缩试验中都出现了一些开裂，但只有 DP780 在断裂行为方面表现出明显的各向异性，T 方向的开裂比 L 方向更为明显。总体而言，试验中观察到的开裂量对轴向压缩性能几乎没有或没有显著影响。使用反向工程方法确定了 L 和 T 方向的 MMC 断裂轨迹，并使用优化方法扩展了超过均匀伸长点的应力-应变曲线。两种材料模型 MAT103 和 MAT224 都能很好地预测 L 和 T 方向轴向压缩试验的压缩和断裂行为。
对于 12 边形构件的轴向压缩试验，预测的断裂模式和力-位移曲线与试验数据吻合较好。简单的各向同性材料模型 MAT224 足以用于压缩模拟，以预测 AHSS 构件压缩性能和断裂行为对材料方向的影响。
