Table 2: The results of modal analysis and orthogonal experimental data with the upper beam.

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

115611612815712038164.10
215811613415912442163.78
316011613215112236164.63
416211612615511640165.39
516411613015311844165.26
615611813015512242163.53
715811812815311636164.55
816011813415711840164.31
916211813215912044164.53
1016411812615112438165.30
1115612012615911836164.01
1215812013015112040163.90
1316012012815512444164.03
1416212013415312238164.43
1516412013215711642164.96
1615612213215312440163.05
1715812212615712244163.66
1816012213015911638164.34
1916212212815111842164.54
2016412213415512036164.77
2115612413415111644162.88
2215812413215511838163.58
2316012412615312042164.01
2416212413015712236164.36
2516412412815912440164.56