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RE: CQC and SRSS

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Adolfo:
Me gustaria saber si tienes alguno de estos libros de elementos finitos o
alguno que tengas que te parezca interesante.


	-	Segerlind,L.J.  "Applied Finite Element Analysis".  John Wiley & Sons
Inc.  N.Y., 1976
	-	Cook, R.D.  "Concepts and Applications of Finite Element Analysis". 
John Wiley and Sons 	Inc., N.Y. 1974.
	Gallagher,R.H.  "Finite Element Analyisis - Fundamentals".  Prentice-Hall
Inc.  Englewood	 	Cliffs, N.J., 1975
	Oñate, E.  "Una Introducción Generalizada al Método de Elementos Finitos".
 Universidad 	Politécnica de Cataluña. Barcelona, 1997.
	-	Bathe,K.J. y Wilson,E.L.  "Numerical Methods in Finite Element
Analysis".  Prentice-Hall Inc.  	Englewood Cliffs, N.J., 1976.

Saludos

Piero Sandro Bengoa Flores 
Engineering Department
COSAPI Ingenieria y Construccion S.A.
Nicolas Arriola Ave 500 Lima 13 -Peru
Ph +51-1-2247666 , Ext 268. Fax +51-1-2248645
e-mail       pbengoa(--nospam--at)cosapi.com.pe
web site   http://www.cosapi.com.pe


----------
De: Adolfo Galvez <agv(--nospam--at)amauta.rcp.net.pe>
A: seaint(--nospam--at)seaint.org
Asunto: Re: CQC and SRSS
Fecha: Jueves 27 de Mayo de 1999 10:54 AM



The classic methods to combine modal responses  to obtain total response
are:

1.- Absolute Sum:    R=SUM abs(Rij); this tend to overestimate the
response, it is very conservative.

2.- SRSS; it is accurate when the modes are well separated but has an
objection: under estimate the response when the modes tend to have similar
frequencies and reach their maximum value almost simultaneously.

3.- Mixed Method, were the absolute sum is used when two modes frequencies
are within 10% of each other, otherwise use SRSS; this method is designed
to overcome the objection in SRSS empirically.

4.- CQC is used to overcome the SRSS objection basing the calculation on
what would arise for a stationary random response. 

 See: A Finite Elements Dynamics Primer. NAFEMS.

Adolfo Galvez