Method for constructing and using three-dimensional thermoforming limit diagram of VRB (Variable Thickness Rolled Blanks)

Abstract

The invention discloses a method for constructing and using a three-dimensional thermoforming limit diagram of VRB (Variable Thickness Rolled Blanks). The method comprises the following steps: 1) measuring basic parameters of a sample material at the temperature below 20 DEG C, wherein the measuring basic parameters are composed of a material thickness anisotropy index r, a material strain hardening index n and a material constant K; 2) utilizing a bulging test to acquire a forming limit curve of equal-thickness blanks in different strain paths corresponding to a certain thickness of the sample material at the temperature below 20 DEG C; 3) converting the forming limit curve of the equal-thickness banks in the different strain paths corresponding to the certain thickness of the sample material into a corresponding forming limit stress curve according to a formula and a corresponding yield criterion; 4) repeating the steps 1-3, forming an FLSC curve of the equal-thickness blanks in different thicknesses at the temperature below 20 DEG C. According to the method provided by the invention, the traditional forming limit strain curve is converted into the forming limit stress curve and is further converted into the three-dimensional thermoforming limit diagram considering the blank thickness and temperature, so that if the VRB can be successfully formed can be more directly and accurately judged.

Description

technical field [0001] The present invention relates to the field of variable thickness rolled blanks (VRB) thermoforming processing, in particular to the establishment and use of a three-dimensional thermoforming limit diagram in consideration of temperature, thickness and other influencing factors during the forming process of variable thickness rolled blanks (VRB) , is mainly used to judge the cracking of the thickened plate (VRB) during hot forming, and evaluate the thermoforming performance of the thickened plate (VRB). Background technique [0002] Sheet metal forming is an important processing method for metal forming, and it is widely used in manufacturing industries such as aerospace, automobile, light industry and household appliances. This is because sheet metal forming has many advantages. First, sheet metal forming has high production efficiency, easy operation, and is easy to realize mechanization and automation. It needs to be machined and processed again, so...

AI Technical Summary

Problems solved by technology

[0009] The problem to be solved by the present invention is to provide a method for establishing and using a three-dimensional thermoforming limit diagram of a variable thickness plate (VRB), which can not only solve the problem that the traditional forming limit diagram is not suitable for predicting the thermoforming performance of a variable thickness plate (VRB), but also It can provide a method that can accurately and conveniently evaluate the fracture location during thermoforming of variable thickness plate (VRB)

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