摘要
分析从辊弯成形型材区和预应变材料取样的材料的拉伸塑性应变。利用概率Weibull累积分布(P-S-N曲线)近似高周疲劳的实验数据。利用LS-Dyna程序和实验数据对辊弯成形进行数值模拟,建立疲劳寿命预测模型。材料的循环行为表明,随着静态失效水平的增加,疲劳寿命分布减小。断裂表面的断口形貌分析表明,由于晶界附近的位错积累,拉伸预应变的晶间裂纹水平增加。所提模型预测结果与概率散射带具有良好的相关性(误差低于10%)。
The tensile plastic strain of material sampled from profiled areas under roller bending and pre-strained material was analyzed.The experimental data of high-cycle fatigue were approximated by a probabilistic Weibull cumulative distribution(P-S-N curve).The fatigue life prediction model was implemented for numerical simulations of roller bending in the LS-Dyna solver and experimental data.The cyclic behaviour of the material shows a decrease in the fatigue life distribution with increasing static failure levels.The fractographic analysis of the fracture surface shows an increased level of intergranular cracking for the tensile pre-strain as a result of the dislocation accumulation in the neighbourhood of grain boundaries.The estimation results of the proposed model show good correlation of probabilistic scatter bands(error below 10%).
基金
The research is co-financed by the European Regional Development Fund under NCBR POIR.04.01.04-00-0006/19 grant,“Cross-belt system for automated sorting of unit loads by a two-stage method”,performed in 2019-2022.
