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

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Fig. 4. Actual input experiment data and predicted design expert best linear fit.

The model have Adeq Precision is (21.144). The "Pred R-Squared" of 0.8602 is in reasonable agreement with the "Adj R-Squared" of 0.8947. The difference is less than 0.2. Adeq Precision" measures the signal to noise ratio. A ratio greater than 4 is desirable. Model ratio of 21.144 indicates an adequate signal. So this model can be used to navigate the design space. Design-Expert provides prediction equations in terms of actual units. Therefore, the final equation in terms of actual factors is:           3 4 3 4 . 10.935 2.470 10 2.174 10 5.7898 1.1075 10 4.5488 10 T S F I T F T I T                 (1) The equation in terms of actual factors can be used to make predictions about the response for given levels of each factor. Numerical optimization will search the design space, using the models created during analysis to find factor settings that meet the defined goals. The goal is maximum tensile strength with optimized parameter so the software predicted parameter for this state (F=2579 N), (I=8247Amp.), (T=38 cycles). The predicted output tensile strength is 4.846 KN, see Figs. 5, 6.

Fig. 5. Interaction between electrode force and welding time parameter