Table 5: Data results of Modal analysis of the lower beam.

Six factors and five levels
The lower plate thicknessThe left and right plate thicknessThe left and right rib plate thicknessThe front and back rib plate thicknessThe front and back plate thicknessThe upper plate thicknessNatural frequency

111696128142170128175.88
211896134144174132176.27
312096132136172126176.48
412296126140166130177.33
512496130138168134178.44
611698130140172132176.11
711898128138166126175.85
812098134142168130176.98
912298132144170134177.72
1012498126136174128176.98
11116100126144168126174.89
12118100130136170130176.15
13120100128140174134176.81
14122100134138172128176.73
15124100132142166134177.90
16116102132138174130175.41
17118102126142172134176.04
18120102130144166128175.89
19122102128136168132176.82
20124102134140170126176.51
21116104134136166134175.99
22118104132140168128175.33
23120104126138170132175.96
24122104130142172126175.57
25124104128144174130176.32