Influence of biaxial tensile specimen gauge area size on yield behavior of DH780
To explore the influence of cruciform biaxial tensile specimen gauge area size on the yield behavior of high strength steel,tak-ing DH780 dual phase steel as the research object,the comparative study of biaxial tensile experiments of specimens with different gauge area sizes was carried out with the reference of ISO standard cruciform specimens.To obtain the same experimental results as the ISO standard specimen,the geometric size of cruciform specimen was optimized by orthogonal experiments.The results show that under equi-biaxial tension condition,the biaxial anisotropy r values obtained by experiments are basically the same as the gauge area size decreases.The biaxial equivalent yield stress decreases first and then increases,the core reason is that the deformation degree of the gauge area of specimens with different sizes is different.For the small cruciform specimen with the gauge area size of 8 mm×8 mm,the influence of the main geometric parameters on the experimental results is ranked as follows:number of slits>radius of fillet between arms>length of slits.The relative difference between the experimental yield loci points of the optimized 8 mm×8 mm new specimen and the 30 mm×30 mm specimen in ISO standard decreases to 2.36%compared with 6.90%of the original specimen.
DH780 steelyield strengthbiaxial tensile experimentgauge area size
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