Method, device, and program of evaluating springback amount of press formed part, and method of manufacturing press formed part

A device for determining an adjusted press forming condition for manufacturing an actual press formed part having improved dimensional accuracy using a press forming die by evaluating a springback amount of a press formed part by comparing a springback amount of an actual press formed part obtained by actually press forming a blank using the press forming die with a springback amount of a press formed part analysis model obtained by elasto-plastic mechanical analysis including a process of press forming the actual press formed part and evaluating the springback amounts of the actual press formed part and the press formed part analysis model, the device comprising:

• a press formed part workpiece shape model acquisition unit configured to:
• generate a press formed part workpiece shape model from three-dimensional surface profile measurement data acquired by measuring a surface profile of the actual press formed part after die release of the actual press formed part and springback thereof,
• perform elastic mechanical analysis including a process of sandwiching the press formed part workpiece shape model up to a forming bottom dead center by a press forming die model of the press forming die, and
• acquire the press formed part workpiece shape model at the forming bottom dead center;
• an actual press formed part springback amount calculation unit configured to:
• perform spring-back analysis by giving a predetermined constraint condition to the press formed part workpiece shape model at the acquired forming bottom dead center, and
• calculate a springback amount generated in the press formed part workpiece shape model as the springback amount of the actual press formed part;
• a press formed part analysis model acquisition unit configured to
• perform the elasto-plastic mechanical analysis including a process of press forming a blank model of the blank by the press forming die model over a single process or a plurality of processes, and
• acquire the press formed part analysis model at the forming bottom dead center;
• a press formed part analysis model springback amount calculation unit configured to:
• perform the spring-back analysis by giving, to the press formed part analysis model at the forming bottom dead center, a same constraint condition as the predetermined constraint condition given to the press formed part workpiece shape model by the actual press formed part springback amount calculation unit, and
• calculate the springback amount generated in the press formed part analysis model;
• and
• a springback amount comparison/evaluation unit configured to:
• compare the springback amount of the actual press formed part calculated in the actual press formed part springback amount calculation unit with the springback amount of the press formed part analysis model calculated by the press formed part analysis model springback amount calculation unit, and
• evaluate the springback amounts of the actual press formed part and the press formed part analysis model,
• wherein the apparatus is configured to further perform, to determine the adjusted press forming condition:
• an analysis condition adjustment step of adjusting an analysis condition of the press formed part analysis model in the mechanical analysis including the process of press forming the actual press formed part and the subsequent springback process so as to improve the acquired prediction accuracy of the springback amount of the press formed part analysis model;
• and
• a press forming condition adjustment step of adjusting the press forming condition in the mechanical analysis including the process of press forming the actual press formed part so as to allow the springback amount of the press formed part analysis model obtained under the adjusted analysis condition to fall within a predetermined range.

A non-transitory computer-readable recording medium on which an executable program for determining an adjusted press forming condition for manufacturing an actual press formed part having improved dimensional accuracy using a press forming die by evaluating a springback amount of a press formed part by comparing a springback amount of an actual press formed part obtained by actually press forming a blank using the press forming die with a springback amount of a press formed part analysis model obtained by elasto-plastic mechanical analysis including a process of press forming the actual press formed part and evaluating the springback amounts of the actual press formed part and the press formed part analysis model, the program causing a processor of a computer to execute:

• a press formed part workpiece shape model acquisition step of generating a press formed part workpiece shape model from three-dimensional surface profile measurement data acquired by measuring a surface profile of the actual press formed part after die release of the actual press formed part and springback thereof, performing elastic mechanical analysis including a process of sandwiching the press formed part workpiece shape model up to a forming bottom dead center by a press forming die model of the press forming die, and acquiring the press formed part workpiece shape model at the forming bottom dead center;
• an actual press formed part springback amount calculation step of performing spring-back analysis by giving a predetermined constraint condition to the acquired press formed part workpiece shape model at the forming bottom dead center and calculating a springback amount generated in the press formed part workpiece shape model as the springback amount of the actual press formed part;
• a press formed part analysis model acquisition step of performing the elasto-plastic mechanical analysis including a process of press forming a blank model of the blank by the press forming die model over a single process or a plurality of processes and acquiring the press formed part analysis model at the forming bottom dead center;
• a press formed part analysis model springback amount calculation step of performing the spring-back analysis by giving, to the press formed part analysis model at the forming bottom dead center, the same constraint condition as the predetermined constraint condition given to the press formed part workpiece shape model in the actual press formed part springback amount calculation step, and calculating the springback amount generated in the press formed part analysis model;
• and
• a springback amount comparison/evaluation step of comparing the springback amount of the actual press formed part calculated in the actual press formed part springback amount calculation step with the springback amount of the press formed part analysis model calculated in the press formed part analysis model springback amount calculation step and evaluating the springback amounts of the actual press formed part and the press formed part analysis model;
• wherein the program is further configured to cause the processor to execute, to determine the adjusted press forming condition:
• an analysis condition adjustment step of adjusting an analysis condition of the press formed part analysis model in the mechanical analysis including the process of press forming the actual press formed part and the subsequent springback process so as to improve the acquired prediction accuracy of the springback amount of the press formed part analysis model;
• and
• a press forming condition adjustment step of adjusting the press forming condition in the mechanical analysis including the process of press forming the actual press formed part so as to allow the springback amount of the press formed part analysis model obtained under the adjusted analysis condition to fall within a predetermined range.