Hi, all,

I did the stress analysis for the pipe under sea condition.

The detailed input and loading combination are listed as followed:

1, W+D1+T1+P1 +WAV1
2, W+D1+T1+P1 +U1+U2+U3
Note:
W: pipe weight
D1: displacement on the pipe end
T1 temperature
P1: pressure
WAV1: wave loading
U1, U2, U3: seismic acceleration, 0.25g

My question:

1.1, W+D1+T1+P1 +WAV1
1.2, W+D1+T1+P1

2.1, W+D1+T1+P1 +U1+U2+U3
2.2, W+D1+T1+P1

Why does the result（bending moment and force） of W+D1+T1+P1 for case 1 and 2 has the difference? I think two results should be same since W+D1+T1+P1 is not changed.

Thanks.

Any time you include WAVx, anywhere in any load case "W" is acctually "W + Buoyancy".