i have a question on Spectrum analysis:
i want to calculate the steam hammer in power plant pipe,and the dynamic analysis was conducted on PIPENET .the"*.DLF" files were created by caesar through "*.FRC" file created by pipenet.
so the questions are:
when "spectrum load cases"is invoked,at the first column,spectrum name is specified separately,here, i have 30 spectrum files,so 30 separated spectrums are specified(see pic02),and,the combination of the 30 spectrum is specified in the 31st load case(see pic01),
and next i invoke the "static/Dynamic combinations"(pic03),to combine a "sus" load with each of the spectrum load cases(pic03)for stress check,this is the first case.and in the"static/Dynamic combinations"(pic04) a sus combine the above specifed combination case D31. this is the second situation.

after calculation,the "sus+D1+D2+...+D30" and the"sus+D31" differs from each other.which method is right
D31 is the combination of D1,D2,...D30(in the"spectrum load cases"window)

thank you very much~~

[img]http://phrenzxh.blog.163.com/editPhoto.d...080074082086095[/img]
[img]http://phrenzxh.blog.163.com/editPhoto.d...080074082086095[/img]
[img]http://phrenzxh.blog.163.com/editPhoto.d...&albumId=-1[/img]
[img]http://phrenzxh.blog.163.com/editPhoto.d...080074082086095[/img]
[img]http://phrenzxh.blog.163.com/editPhoto.d...080074082086095[/img]
http://phrenzxh.blog.163.com/editPhoto.d...080074082086095