Bond_SP01.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 **                                                                    **
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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: 2006/08/03 22:06:26 $
00023                                                                         
00024 // Written:             Jian Zhao, Iowa State University                04/2004
00025 // Revision:            Jian Zhao, University of Wisconsin, Milwaukee           04/2006
00026 //
00027 // Description: This file contains the class defination for Uniaxial material Bond_SP01. 
00028 //              Bond_SP01: Strain penetration of rebars at footings w/o bond damage.
00029 /* *********************************************************************** **
00030 ** Nonlinear material model with Menegoto-Pinto type functions to define   **
00031 ** envelope curve and loading-unloading-reloading curve.  test data of     **
00032 ** rebar stress vs. rebar slip is needed to calibrate the model.           **
00033 ** *********************************************************************** */
00034 
00035 #ifndef Bond_SP01_h
00036 #define Bond_SP01_h
00037 
00038 #include <UniaxialMaterial.h>
00039 #include <math.h>
00040 #include <Matrix.h>
00041 #include <Vector.h>
00042 
00043 class Bond_SP01 : public UniaxialMaterial
00044 {
00045   public:
00046     Bond_SP01(int tag, double fy, double sy, double fu, double su, double Kz, double R, double Cd, double db, double fc, double la); 
00047     Bond_SP01(int tag, double fy, double sy, double fu, double su, double Kz, double R); 
00048     Bond_SP01();
00049     ~Bond_SP01();
00050 
00051     const char *getClassType(void) const {return "Bond_SP01";};   
00052 
00053     int setTrialStrain (double strain, double strainRate = 0.0); 
00054     int setTrial (double strain, double &stress, double &tangent, double strainRate = 0.0);
00055     double getStrain(void);              
00056     double getStress(void);
00057     double getTangent(void);
00058     double getInitialTangent(void);
00059 
00060     int commitState(void);
00061     int revertToLastCommit(void);    
00062     int revertToStart(void);        
00063 
00064     UniaxialMaterial *getCopy(void);
00065     
00066     int sendSelf(int commitTag, Channel &theChannel);  
00067     int recvSelf(int commitTag, Channel &theChannel, 
00068                  FEM_ObjectBroker &theBroker);    
00069     
00070     void Print(OPS_Stream &s, int flag =0);
00071     
00072   protected:
00073     
00074   private:
00075     /*** anchorage condition ***/
00076     double db;                  // rebar diameter
00077     double fc;                  // concrete compressive strength (positive ksi)
00078     double lba;                 // bond length (can be shorter than current set -> rigid-body slip)
00079     double la;                  // required minimum anchorage length
00080     
00081     /*** strain penetration ***/
00082     double sy;                  // rebar slip at bar yielding
00083     double su;                  // rebar slip at bar failure (assume @ 1.5fy)
00084     double fy;                  // bar yield strength
00085     double fu;                  // bar ultimate strength (assume @ 1.5fy)
00086     double E0;                  // initial slope of the envelope
00087     double Kz;                  // initial hardening ratio (0.3), 0.25<Kz<0.5
00088     double Cr;                  // R factor for the envelope using menegoto-pinto curve
00089     double Ks;                  // reloading stop point (to avoid infinity slope with pinching)
00090     
00091     /*** pinching condition ***/
00092     double R;                   // R factor for reloading using menegoto-pinto type curve
00093     double Cd;                  // bond damage factor (currently no use)
00094     
00095     /*** CONVERGED History Variables ***/
00096     double CRSlip;              // return slip
00097     double CRLoad;              // return load
00098     double CRSlope;             // return slope
00099     double CmaxHSlip;   // Maximum slip in tension
00100     double CminHSlip;   // Maximum slip in compression
00101     int Cloading;       // Flag for Stressing/unStressing
00102                         // 1 = loading (positive slip increment)
00103                         // -1 = unloaading (negative slip increment)
00104                         // 0 = initial state
00105     int CYieldFlag;             // Flag for yielding
00106                                 // 1 = yielded
00107                                 // 0 = not yielded
00108 
00109     /*** CONVERGED State Variables ***/    
00110     double Cslip;
00111     double Cload;
00112     double Ctangent;    
00113 
00114     /*** TRIAL History Variables ***/
00115     double TRSlip;              // return slip
00116     double TRLoad;              // return load
00117     double TRSlope;             // return slope
00118     double TmaxHSlip;   // Maximum slip in tension
00119     double TminHSlip;   // Maximum slip in compression
00120     int Tloading;       // Flag for Stressing/unStressing
00121     int TYieldFlag;             // Flag for yielding
00122     
00123     /*** TRIAL State Variables ***/
00124     double Tslip;
00125     double Tload;
00126     double Ttangent;    
00127 
00128     // Calculates the trial state variables based on the trial Strain
00129     void determineTrialState (double tslip, double dslip);
00130     
00131     // Calculates envelope stress for a slip
00132     double getEnvelopeStress (double slip);
00133     
00134     // Determines if a Stress reversal has occurred based on the trial Strain
00135     void detectStressReversal (double dslip);
00136 };
00137 #endif

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