*3.4. Response Surface Analysis*

3.4.1. Response Surface Model Fitting

By fitting the data in Tables 2 and 3 with the least square method, six response models were obtained, which are expressed as:


3.4.2. Response Surface Model Validation

To verify the statistical relationship between the structure and the selected random variables, the accuracy of the six fitted response surface models was tested. The results are shown in Table 4.

**Table 4.** Accuracy tests of response surface models.


As shown in Table 4, the average value of the six response surfaces is 0.9091. More than 90% is due to changes in the model parameters, indicating that the model has high fitting accuracy and is more reliable.
