response spectra is required to find out the frequency of nodal point at
different time and to analyse that this frequency should not be same with
the natural frequency to avoid resonance.From time history response
spectra is generated. If you get response spectra then the analysis will be
easy and time convenient. Generally we get the response spectra of ground
level.From this depending upon the position multilevel response spectra
have to be generated.It is more correct method.
In earthquake analysis in nuclear sector there are several conditions of
earthquake such as operating basis earthquake, safe shutdown earthquake and
several class of piping depending upon the safety considerations such as
class one, class two, class three. For all the conditions different codes
are there and from codes we can find out the allowable stresses. Generally
in dynamic analysis the pipes are considered as in plastic state,so
allowable stresses are higher than the allowable stress defined in codes in
static condition.
calculated stress depends upon the supporting criteria and layout.Generally
in dynamic more rigid supporting arrangement is required i.e decreament of
flexibility....so in thermal case it may create problem. For that some
special supports are there such as snubbers.
gautam wayse <captain_wayse@yahoo.co.in> on 12/28/2004 10:24:36 AM
Please respond to PipingDesign@yahoogroups.com
To: PipingDesign@yahoogroups.com
cc: (bcc: Suman Banerjee/Consultant/JAMNAGAR/RIL)
Subject: [PipingDesign] dynamic stress analysis .
dear friend
if some one working on dynamic analysis and having
expertise in same .please solve my fallowing problems
.
why it is essential to perform modal frequency
response and time histry analysis .
how much differece (in per cent )one can expect in
calculated stress
value at static condition and dynamic cases.
gautam wayse
Yahoo! Groups Links Received on Wed Dec 29 03:01:00 2004
This archive was generated by hypermail 2.1.8 : Mon Oct 27 2008 - 20:24:06 EDT