PLOTTING OF SHEET MATERIAL LIMITING STRAINS DIAGRAM Russian patent published in 2015 - IPC G01N3/28 

FIELD: process engineering.

SUBSTANCE: invention relates to plate forging, particularly, to analysis of properties of sheets for evaluation of forge ability and for application in CAD/CAE systems at computer simulation and designing of forming jobs. In consists in that diagram of limiting strain is plotted by relative elongation δ_u as per GOST 11701-84. Then, ordinate ln(1+δ_u) of the point of limiting strain diagram is calculated. Then, abscissa -0.5ln(1+δ_u) of said first point is calculates for model of linear extension of isotropic specimen. Plotted first point us used to draw a straight-line segment at 45 degrees to Y-line to intersection therewith at second point. Third point is obtained with abscissa and ordinate ln(1+δ_u) to connect second and third pints with straight-line segment. Straight-like segment ε₁=ε₂ to fourth point with abscissa and ordinate 3ln(1+δ_u). Note here that straight-like segment passing through first and second points is extended to the left to fifth points with abscissa -ln(1+δ_u).

EFFECT: accelerated and high-quality designing, saving if sheet material, simplified selection of sheet material and forging equipment.

2 cl, 1 dwg