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NewmarkExplicit.h

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00001 /* ****************************************************************** **
00002 **    OpenSees - Open System for Earthquake Engineering Simulation    **
00003 **          Pacific Earthquake Engineering Research Center            **
00004 **                                                                    **
00005 **                                                                    **
00006 ** (C) Copyright 1999, The Regents of the University of California    **
00007 ** All Rights Reserved.                                               **
00008 **                                                                    **
00009 ** Commercial use of this program without express permission of the   **
00010 ** University of California, Berkeley, is strictly prohibited.  See   **
00011 ** file 'COPYRIGHT'  in main directory for information on usage and   **
00012 ** redistribution,  and for a DISCLAIMER OF ALL WARRANTIES.           **
00013 **                                                                    **
00014 ** Developed by:                                                      **
00015 **   Frank McKenna (fmckenna@ce.berkeley.edu)                         **
00016 **   Gregory L. Fenves (fenves@ce.berkeley.edu)                       **
00017 **   Filip C. Filippou (filippou@ce.berkeley.edu)                     **
00018 **                                                                    **
00019 ** ****************************************************************** */
00020 
00021 // $Revision: 1.2 $
00022 // $Date: 2005/12/21 00:32:57 $
00023 // $Source: /usr/local/cvs/OpenSees/SRC/analysis/integrator/NewmarkExplicit.h,v $
00024 
00025 
00026 #ifndef NewmarkExplicit_h
00027 #define NewmarkExplicit_h
00028 
00029 // Written: Andreas Schellenberg (andreas.schellenberg@gmx.net) 
00030 // Created: 02/05
00031 // Revision: A
00032 //
00033 // Description: This file contains the class definition for NewmarkExplicit.
00034 // NewmarkExplicit is an algorithmic class for performing a transient analysis
00035 // using the explicit Newmark integration scheme (beta = 0).
00036 //
00037 // What: "@(#) NewmarkExplicit.h, revA"
00038 
00039 #include <TransientIntegrator.h>
00040 
00041 class DOF_Group;
00042 class FE_Element;
00043 class Vector;
00044 
00045 class NewmarkExplicit : public TransientIntegrator
00046 {
00047 public:
00048     // constructors
00049     NewmarkExplicit();
00050     NewmarkExplicit(double gamma);
00051     NewmarkExplicit(double gamma, double alphaM, double betaK, double betaKi, double betaKc); 
00052     
00053     // destructor
00054     ~NewmarkExplicit();
00055     
00056     // methods which define what the FE_Element and DOF_Groups add
00057     // to the system of equation object.
00058     int formEleTangent(FE_Element *theEle);
00059     int formNodTangent(DOF_Group *theDof);        
00060     
00061     int domainChanged(void);    
00062     int newStep(double deltaT);    
00063     int revertToLastStep(void);            
00064     int update(const Vector &aiPlusOne);
00065     
00066     virtual int sendSelf(int commitTag, Channel &theChannel);
00067     virtual int recvSelf(int commitTag, Channel &theChannel, FEM_ObjectBroker &theBroker);
00068     
00069     void Print(OPS_Stream &s, int flag = 0);        
00070     
00071 protected:
00072     
00073 private:
00074     double gamma;
00075 
00076     // rayleigh damping factors
00077     double alphaM;
00078     double betaK;
00079     double betaKi;
00080     double betaKc;
00081 
00082     int updateCount;                // method should only have one update per step
00083     double c2, c3;                  // some constants we need to keep
00084     Vector *Ut, *Utdot, *Utdotdot;  // response quantities at time t
00085     Vector *U, *Udot, *Udotdot;     // response quantities at time t+deltaT
00086 };
00087 
00088 #endif

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