A508-Ⅲ钢小尺寸样品拉伸行为的有限元辅助测试方法研究

Study on Tensile Behavior of Small Size Specimen of A508-ⅢSteel Based on Finite Element Aided Testing Method

为了克服拉伸样品尺寸减小所带来的尺寸效应的影响,本文对A508-Ⅲ钢小尺寸样品的拉伸行为进行了研究。通过改变A508-Ⅲ钢的热处理温度制备了不同晶粒尺寸和样品厚度的小尺寸样品,进行了小尺寸样品的室温拉伸测试,分析了晶粒尺寸和样品厚度对小尺寸样品拉伸力学性能的影响,并揭示了其潜在的拉伸尺寸效应机理。结果表明,由于小尺寸样品厚度和晶粒尺寸的变化,导致其拉伸力学性能表现出明显的尺寸效应;通过引入综合表征样品特征尺寸和晶粒尺寸效应的影响参数,构建了考虑尺寸效应的Swift力学本构模型;采用有限元辅助测试方法确定了小尺寸样品的延性损伤演变参数,数值与实验结果误差小于3%;基于建立的力学本构模型,利用有限元方法预测了小尺寸样品的拉伸力学性能,构建了其屈服强度与抗拉强度的归一化模型,以期为小尺寸样品的工程应用提供借鉴。

In order to overcome the influence of size effect brought about by the reduction in the size of tensile specimen,the tensile properties have been investigated for small size specimens of A508-Ⅲsteel in this paper.The small size specimens of A508-Ⅲsteel with varying grain sizes and specimen thicknesses were prepared by altering the heat treatment temperature,and their tensile tests were conducted at room temperature.The effects of grain size and thickness on the tensile mechanical properties of small size specimens were analyzed and the underlying mechanism of the potential tensile size effect was revealed.The results indicate that,due to the changes in the thickness and grain size of small size specimens,the tensile mechanical property exhibits an obvious size effect.A Swift mechanical constitutive model considering size effects was developed by introducing influence parameters that comprehensively characterize the specimen feature size and grain size effects.The ductile damage evolution parameters of the specimens were determined using the finite element aided testing(FAT)method,and the error between numerical and experimental results was less than 3%.Based on the established mechanical constitutive model,the tensile mechanical properties of the small size specimens were predicted using the finite element method,and the normalized models of their yield strength and tensile strength were constructed,so as to provide reference for the engineering application of small size specimens.