贯通式Nakajima模型在预测不同厚度钢板成形性中的应用

Application of thru-Nakajima model to predict formability of steel sheet with different thickness

在AutoForm中创建贯通式Nakajima模型,将钢板属性加载到模型中并仿真,分析了最大失效值随板厚增大时的变化趋势。结果显示,多数材料最大失效值均随厚度增大而降低,但存在以下3种不同情况:①常规深冲钢,如DC06在进行双向等拉、一般胀形及平面应变时,0.8 mm和1.6 mm厚时最大失效值偏低,而1.2 mm厚时最高;②特种深冲钢,如DC57D+Z钢,0.8 mm厚时最大失效值偏高,而其进行等向双拉和双拉胀形时,0.8、1.2mm厚时该值不变;③高碳合金钢,当屈服强度为280~400 MPa,最大失效值变化趋势呈现多样性,如HC340LA,对平面应变、类似单向拉伸或拉压变形,该值随厚度增大而降低,而对其他变形类型,随厚度增大先降低后升高,其中0.8 mm厚时该值最高,1.2 mm厚时最低,镀锌板HC340-590DPD-Z在发生双拉变形时,随厚度增大该值逐渐降低,而对于平面应变和接近单向拉伸的变形,1.2 mm厚时该值最高,HC340-590DP钢板在所有类型的变形中,该值均随厚度增大先降低后升高,其中1.2 mm厚时该值最低;④超高强度钢,如HC420-780DPD-Z,在发生双拉变形时,1.2 mm厚的最大失效值最高,对于副应变较大的变形,0.8、1.2 mm厚的该值接近且偏低,而对于非镀锌板HC420-780DP,该值随厚度增大均降低。

The thru-Nakajima model was created in AutoForm,and the properties of steel plate were loaded into the model and simulated,the variation trend of maximum failure value with the increase of plate thickness was analyzed.The results showed that the maximum failure value of most materials decreases with the increase of thickness,but there are three different case:①Themaximum failure value of conventional deep-drawing steel is low at 0.8 mm and 1.6 mm thickness,and is highest at 1.2 mm thickness when the steel is subjected to equal biaxial stretching,general bulging and plane strain,such as DC06;②The maximum failure value of special deep-drawing steel is high when it is 0.8 mm thickness,and when it is equal biaxial stretching and biaxial stretch-ing bulging,the value is unchanged when it is 0.8 mm and 1.2 mm thickness,such as DC57D+Z steel;③When the yield strength of high carbon alloy steel is 280~400 MPa,the variation trend of the maximum failure value is diversity,such as HC340LA,for plane strain,similar uniaxial stretch-ing or tension-compression deformation,the value decreases with the increase of thickness,while for other deformation types,the value decreases first and then increases with the increase of thick-ness,among which the value is the highest at 0.8 mm thickness and the lowest at 1.2 mm thickness.When the galvanized sheet HC340-590DPD-Z is subjected to biaxial stretching deformation,the maximum failure value gradually decreases with the increase of thickness,and the value is highest when the thickness is 1.2 mm for plane strain and near uniaxial stretching deformation.The maxi-mum failure value of HC340-590DP steel plate decreases first and then increases with thickness in all types of deformation,and the value is the lowest when the thickness is 1.2 mm.④When the ul-tra-high strength steel is subjected to biaxial stretching deformation,the maximum failure value of 1.2 mm thickness is the highest,the value of 0.8 mm and 1.2 mm thickness are close and low for the deformation with large secondary strain,such as HC420-780DPD-Z,while for non-galvanized plate HC420-780DP,the value decreases with the increase of thickness.