Hot stamping of high strength steels is defined as a process in which blank is heated to the temperature of the austenite stabilization region for a definite time and then formed and quenched simultaneously in a mold ...Hot stamping of high strength steels is defined as a process in which blank is heated to the temperature of the austenite stabilization region for a definite time and then formed and quenched simultaneously in a mold with cooling channels. During this process,the processing parameters of austenite temperature and soaking time have strong effects on the mechanical properties such as quenching hardness,tensile strength and elongation. Hence,it is necessary to investigate the relationship between the mechanical properties and the two processing parameters. In this paper,the orthogonal experiment with two factors and five levels was applied, and the experimental data based on the orthogonal experiment was acquired. Based on the data,regression models were set up and the results of the analysis of variance( ANOVA) showed that it is reliable to predict the quenching hardness,tensile strength and elongation by the regression models. Besides,the optimal results of each single object were obtained based on response surface methodology( RSM),and global optimums was gained by employing ideal point method in which the quenching hardness,and tensile strength and elongation were considered simultaneously.展开更多
为研究不同力组合效应对平齐端板连接力学行为的影响,采用ABAQUS程序建立不同受力情况下连接的非线性简化有限元模型,通过与国内外典型试验结果对比分析,验证了有限元模型的可靠性。基于此通过考虑8种力组合因素的影响,分析了2种不同钢...为研究不同力组合效应对平齐端板连接力学行为的影响,采用ABAQUS程序建立不同受力情况下连接的非线性简化有限元模型,通过与国内外典型试验结果对比分析,验证了有限元模型的可靠性。基于此通过考虑8种力组合因素的影响,分析了2种不同钢等级的梁柱节点力学行为,进一步讨论了EC3 Part 1-8规范的适用性。结果表明:简化有限元模型在弯矩-转角曲线、破坏形态、初始刚度和塑性抗力等方面与试验结果吻合良好。框架梁轴力对节点的力学行为影响显著,当轴拉力为20%的框架梁轴向塑性抗力N_(pl)时,高强钢节点的刚度和强度分别降低68%和52%;当轴压力为-20%N_(pl)时,刚度和强度分别增加89%和42%。此外节点的滞回耗能能力、破坏模式以及分类属性与梁轴力水平密切相关。对于高强钢梁柱平齐端板节点,EC3规范对框架梁轴压力的限值仍过于保守。研究结果对于提高结构的抗倒塌能力和组合力作用下的理论研究具有重要参考价值。展开更多
基金Sponsored by Automotive High-strength Stell Stampings Thermoforming Process(Grant No.10211653)
文摘Hot stamping of high strength steels is defined as a process in which blank is heated to the temperature of the austenite stabilization region for a definite time and then formed and quenched simultaneously in a mold with cooling channels. During this process,the processing parameters of austenite temperature and soaking time have strong effects on the mechanical properties such as quenching hardness,tensile strength and elongation. Hence,it is necessary to investigate the relationship between the mechanical properties and the two processing parameters. In this paper,the orthogonal experiment with two factors and five levels was applied, and the experimental data based on the orthogonal experiment was acquired. Based on the data,regression models were set up and the results of the analysis of variance( ANOVA) showed that it is reliable to predict the quenching hardness,tensile strength and elongation by the regression models. Besides,the optimal results of each single object were obtained based on response surface methodology( RSM),and global optimums was gained by employing ideal point method in which the quenching hardness,and tensile strength and elongation were considered simultaneously.
文摘为研究不同力组合效应对平齐端板连接力学行为的影响,采用ABAQUS程序建立不同受力情况下连接的非线性简化有限元模型,通过与国内外典型试验结果对比分析,验证了有限元模型的可靠性。基于此通过考虑8种力组合因素的影响,分析了2种不同钢等级的梁柱节点力学行为,进一步讨论了EC3 Part 1-8规范的适用性。结果表明:简化有限元模型在弯矩-转角曲线、破坏形态、初始刚度和塑性抗力等方面与试验结果吻合良好。框架梁轴力对节点的力学行为影响显著,当轴拉力为20%的框架梁轴向塑性抗力N_(pl)时,高强钢节点的刚度和强度分别降低68%和52%;当轴压力为-20%N_(pl)时,刚度和强度分别增加89%和42%。此外节点的滞回耗能能力、破坏模式以及分类属性与梁轴力水平密切相关。对于高强钢梁柱平齐端板节点,EC3规范对框架梁轴压力的限值仍过于保守。研究结果对于提高结构的抗倒塌能力和组合力作用下的理论研究具有重要参考价值。
