PSI- Issue 9

Tareq Rahman Mahmood et al. / Procedia Structural Integrity 9 (2018) 71–85 Tareq RahmanMahmood, et al. / Structural Integrity Procedia 00 (2018) 000–000

78

8

Table 5: ANOVA table model Analysis for low carbon steel with sheet thickness 0.9 mm. Source Sum of Squares df Mean Square F Value p-value Prob > F Model 77.90 4 19.48 75.84 < 0.0001

significant

A-electrode force B-welding current C-welding time

1.12

1 1 1 1

1.12

4.36

0.0486

76.66

76.66

298.53

< 0.0001

0.26 0.53

0.26 0.53

1.03 2.06

0.3210 0.1654

AC

Residual

5.65

22

0.26

The Model have F-value of 75.84 implies so the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. Values of "Prob > F" less than 0.0500 indicate model terms are significant. Model of this state have Adeq Precision equal to (30.5109). The "Pred R-Squared" of 0.8934 is in reasonable agreement with the "Adj R-Squared" of 0.9201, and the difference is less than 0.2. The equation in terms of actual factors can be used to make predictions about the response for given levels of each factor is:         3 3 3 . 1.4622 3.8110 10 1.6411 10 2.9385 1.43075 10 T S F I T F T             (2) Figure 8 shows all 27 trails run that plot in comparison between experiment strength results and predicted results the square point in the figure have different color this color change from blue (specimens with parameters condition have less tensile strength value) to red (specimens with welding parameters causes large tensile strength) the Straight line represented the predicted value by program software.

Fig. 8. Plot of actual input experiment data and predicted design expert best linear fit

The software predicted the parameters for F=2198 N, I=8243Amp, T=37cycles. Hence, the predicted output tensile strength is 7.06439 KN. Therefore, the welding in these parameters will result tensile strengths similar to those predicted, see Fig. 9.