Method for establishing and using forming limit diagram of laser tailor-welded blank

Abstract

The invention discloses a method for establishing a forming limit diagram of a laser tailor-welded blank. The method comprises the following steps: (A) establishing an XY coordinate system of which the X represents a direction perpendicular to the direction of a welding seam and the Y represents the direction parallel to the direction of the welding seam; (B) calculating an ultimate strain of a material in a welding zone by adopting an empirical formula and combining with performance parameters of the material, and then, based on stress strain relation of the material in the welding zone and weak side parent metal, calculating to obtain weak side parent metal FLC by combining with the performance parameters of the weak side parent metal when the material in the welding zone is invalid, namely, Y-direction strain is larger than X-direction strain; (C) calculating the weak side parent metal FLC when the weak side parent metal is invalid, namely, the Y-direction strain is smaller than the X-direction strain by adopting the empirical formula and combining with the performance parameters of the weak side parent metal; and (D) marking the weak side parent metal FLCs obtained in step (B)and step (C) into an XY direction strain coordinate system at the same time to establish the forming limit diagram of the laser tailor-welded blank. The method can establish the forming limit diagramof the laser tailor-welded blank suitable for engineering application to effectively evaluate forming limit of the tailor-welded blank.

Description

technical field [0001] The invention relates to the field of sheet metal forming processing, and relates to a method for establishing and using a failure criterion for laser tailor welded blanks with differential thickness, which is mainly used for accurately judging the necking or cracking of laser tailor welded blanks with differential thickness, and evaluating its formability. Background technique [0002] Tailored welded blanks refer to two or more sheets of different thicknesses, different materials and different surface conditions that are welded by laser to form a whole sheet, and then stamped to meet the different properties of the sheets at different positions of the stamping parts. Require. Laser tailor welded blanks are widely used in the automobile industry due to their advantages of reducing body weight, improving safety performance and reducing manufacturing costs. Tailored welded blanks are used in the central passage and door inner panels of Shanghai Volkswa...

AI Technical Summary

Problems solved by technology

However, due to the small width and high hardness of the weld, it is difficult to obtain the primary and secondary strains at the failure point, which brings difficulties to the establishment of FLD in the weld area; on the other hand, the FLD of a single plate cannot evaluate the failure of the weak side. Weld plate formability

[0012] As mentioned above, so far, the existing evaluation methods for tailor welded blanks have limitations, and there is an urgent need to accurately judge and evaluate the formability of tailor welded blanks in engineering, so as to provide guidance for actual stamping production

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