采用应变梯度硬化模型预测黄铜薄板微弯曲弯矩

Microbending Moment of Brass Foils Based on Strain Gradient Hardening Model

通过黄铜板料微弯曲实验,发现其弯曲弯矩存在明显的尺寸效应现象,随板料厚度的减小,弯曲弯矩增大.采用经典塑性理论和不同的应变梯度理论对微弯曲弯矩进行了预测,对比分析结果表明:修正的Nix-Gao模型的预测结果更接近于实验结果,并且得出了合理的内禀尺寸表达式;该内禀尺寸与材料的剪切模量、初始屈服极限、柏氏矢量和板料厚度方向上的孪晶数有关.

The microbending experiments of brass were investigated and there exist the obvious size effects that bending moment increases with foil thickness decreasing.The microbending moments are predicted by classical plastic theory and different strain gradient theories,which shows that the predicted results based on the modified Nix-Gao model are very close to the experimental data and the equation of material intrinsic length is reasonable.The material intrinsic length is the function of shear modulus,initial yield strength,Burger＇s vector and twins layers across the foil thickness.