Line displacement evaluation method, line displacement evaluation device, program, and recording medium

1. A line displacement evaluation method of evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the method comprising:

acquiring a cross section profile of the press-formed article measured so as to traverse the character line formed in the press-formed article;

calculating a 4th order differential coefficient of the acquired cross section profile; and

evaluating the line displacement, on the basis of the calculated 4th order differential coefficient of the cross section profile,

wherein in the evaluating, a peak value H of the 4th order differential coefficient of the cross section profile on a side area of the character line where the line displacement occurs, and a displacement width L between a position where the peak value H appears and a position of an R stop of a design character line on the side area where the line displacement occurs are determined, and the line displacement is evaluated using the peak value H and the displacement width L, and

wherein in the evaluating a first line displacement evaluation parameter S is calculated from the following Formula (1), and the line displacement is evaluated using the calculated first line displacement evaluation parameter S,

S=L×|H| n   (1)

here, n is a weighting index that is determined in advance.

2. The line displacement evaluation method according to claim 1 , the method further comprising outputting the line displacement that was evaluated to determine the quality of the press-formed article.

3. A line displacement evaluation device of evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the device comprising:

a cross sectional profile acquisition processing circuitry configured to acquire a cross section profile of the press-formed article measured so as to traverse the character line formed in the press-formed article;

a 4th order differential coefficient calculation processing circuitry configured to calculate a 4th order differential coefficient of the cross section profile acquired in the cross section profile acquisition processing circuitry;

a line displacement evaluation parameter calculation processing circuitry configured to calculate a line displacement evaluation parameter for evaluating the line displacement, on the basis of the 4th order differential coefficient of the cross section profile calculated in the 4th order differential coefficient calculation processing circuitry; and

a line displacement evaluation processing circuitry configured to evaluate the line displacement, on the basis of the line displacement evaluation parameter calculated in the line displacement evaluation parameter calculation processing circuitry,

wherein the line displacement evaluation parameter calculation processing circuitry determines a peak value H of the 4th order differential coefficient of the cross section profile on a side area of the character line where the line displacement occurs, and a displacement width L between a position where the peak value H appears and a position of an R stop of a design character line on the side area where the line displacement occurs, and calculates the line displacement evaluation parameter using the peak value H and the displacement width L,

wherein the line displacement evaluation parameter calculation processing circuitry calculates a line displacement evaluation parameter S from the following Formula (1),

S=L×|H| n   (1)

here, n is a weighting index that is determined in advance.

4. The line displacement evaluation device according to claim 3 , wherein the line displacement evaluation processing circuitry outputs the line displacement that was evaluated to determine the quality of the press-formed article.

5. A non-transitory computer readable medium encoded with a computer program for evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the program causing a computer to execute:

processing of acquiring a cross section profile of the press-formed article measured so as to traverse the character line formed in the press-formed article;

processing of calculating a 4th order differential coefficient of the acquired cross section profile;

processing of calculating the line displacement evaluation parameter for evaluating the line displacement, on the basis of the calculated 4th order differential coefficient of the cross section profile; and

processing of evaluating the line displacement, on the basis of the calculated line displacement evaluation parameter,

wherein in the processing of calculating the line displacement evaluation parameter, a peak value H of the 4th order differential coefficient of the cross section profile on a side area of the character line where the line displacement occurs, and a displacement width L between a position where the peak value H appears and a position of an R stop of a design character line on the side area where the line displacement occurs are determined, and the line displacement evaluation parameter is calculated using the peak value H and the displacement width L, and

wherein in the processing of calculating the line displacement evaluation parameter, a line displacement evaluation parameter S is calculated from the following Formula (1),

S=L×|H| n   (1)

here, n is a weighting index that is determined in advance.

6. The non-transitory computer readable medium according to claim 5 encoded with a computer program for evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the program causing a computer to further execute processing of outputting the line displacement that was evaluated to determine the quality of the press-formed article.

7. A line displacement evaluation method of evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the method comprising:

acquiring a cross section profile of the press-formed article measured so as to traverse the character line formed in the press-formed article;

calculating a 4th order differential coefficient of the acquired cross section profile; and

evaluating the line displacement, on the basis of the calculated 4th order differential coefficient of the cross section profile,

wherein in the evaluating, a peak value H of the 4th order differential coefficient of the cross section profile on a side area of the character line where the line displacement occurs, and a displacement width L between a position where the peak value H appears and a position of an R stop of a design character line on the side area where the line displacement occurs are determined, and the line displacement is evaluated using the peak value H and the displacement width L,

wherein in the evaluating, a curve radius R of the character line is further determined, and the line displacement is evaluated using the peak value H, the displacement width L, and the curve radius R, and a second line displacement evaluation parameter S II is calculated from the following Formula (2), and the line displacement is evaluated using the calculated second line displacement evaluation parameter S II ,

S II =L ×(| H|/R ) m   (2)

Here, m is a weighting index that is determined in advance, and R is the curve radius.

8. The line displacement evaluation method according to claim 7 , the method further comprising outputting the line displacement that was evaluated to determine the quality of the press-formed article.

9. A line displacement evaluation device of evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the device comprising:

a cross sectional profile acquisition processing circuitry configured to acquire a cross section profile of the press-formed article measured so as to traverse the character line formed in the press-formed article;

a 4th order differential coefficient calculation processing circuitry configured to calculate a 4th order differential coefficient of the cross section profile acquired in the cross section profile acquisition processing circuitry;

a line displacement evaluation parameter calculation processing circuitry configured to calculate a line displacement evaluation parameter for evaluating the line displacement, on the basis of the 4th order differential coefficient of the cross section profile calculated in the 4th order differential coefficient calculation processing circuitry; and

a line displacement evaluation processing circuitry configured to evaluate the line displacement, on the basis of the line displacement evaluation parameter calculated in the line displacement evaluation parameter calculation processing circuitry,

wherein the line displacement evaluation parameter calculation processing circuitry determines a peak value H of the 4th order differential coefficient of the cross section profile on a side area of the character line where the line displacement occurs, and a displacement width L between a position where the peak value H appears and a position of an R stop of a design character line on the side area where the line displacement occurs, and calculates the line displacement evaluation parameter using the peak value H and the displacement width L,

wherein the line displacement evaluation parameter calculation processing circuitry further determines a curve radius R of the character line, and calculates the line displacement evaluation parameter using the peak value H, the displacement width L, and the curve radius R, and

wherein the line displacement evaluation parameter calculation processing circuitry calculates a line displacement evaluation parameter S II from the following Formula (2),

S II =L ×(| H|/R ) m   (2)

Here, m is a weighting index that is determined in advance, and R is the curve radius.

10. The line displacement evaluation device according to claim 9 , wherein the line displacement evaluation processing circuitry outputs the line displacement that was evaluated to determine the quality of the press-formed article.

11. A non-transitory computer readable medium encoded with a computer program for evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the program causing a computer to execute:

processing of acquiring a cross section profile of the press-formed article measured so as to traverse the character line formed in the press-formed article;

processing of calculating a 4th order differential coefficient of the acquired cross section profile;

processing of calculating the line displacement evaluation parameter for evaluating the line displacement, on the basis of the calculated 4th order differential coefficient of the cross section profile; and

processing of evaluating the line displacement, on the basis of the calculated line displacement evaluation parameter,

wherein in the processing of calculating the line displacement evaluation parameter, a peak value H of the 4th order differential coefficient of the cross section profile on a side area of the character line where the line displacement occurs, and a displacement width L between a position where the peak value H appears and a position of an R stop of a design character line on the side area where the line displacement occurs are determined, and the line displacement evaluation parameter is calculated using the peak value H and the displacement width L,

wherein in the processing of calculating the line displacement evaluation parameter, a curve radius R of the character line is determined, and the line displacement evaluation parameter is calculated using the peak value H, the displacement width L, and the curve radius R, and

wherein in the processing of calculating the line displacement evaluation parameter, a line displacement evaluation parameter S II is calculated from the following Formula (2),

S II =L ×(| H|/R ) m   (2)

Here, m is a weighting index that is determined in advance, and R is the curve radius.

12. The non-transitory computer readable medium according to claim 11 encoded with a computer program for evaluating line displacement occurring in a press-formed article in press forming of forming a character line, the program causing a computer to further execute processing of outputting the line displacement that was evaluated to determine the quality of the press-formed article.