====== Appendix 22: Structure of CONEC and SIGVA ======
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===== CONEC =====
==== Structure ====
The CONEC matrix contains **nodal** values. It is structured as follows: \\
CONEC(INP, ISPAC, ICONE) where:
* INP is the node number (INP=1,NUMNP)
* ISPAC is the DOF number (ISPAC=1,NSPAC - see definition depending on value of [[:prepro#(1) Remark on NTANA|NTANA]])
* ICONE defines a particular nodal value (ICONE=1,NCONE)
The nodal value defined by ICONE depends on the type of analysis. In the following paragraph, index $0$ indicates the beginning of the time step, and index $1$ indicates the end of the time step. \\ \\
__1. Static analysis__
^ ICONE ^ Nodal value ^
| 1 | $X_1$ |
| 2 | $X_0$ |
| 3 | $\dot{X}_0$ |
| 4 | $DX$ if IMDIS=1 |
\\
__2. Dynamic analysis__
^ ICONE ^ Nodal value ^
| 1 | $X_1$ |
| 2 | $X_0$ |
| 3 | $\dot{X}_0$ |
| 4 | $\ddot{X}_0$ |
| 5 | $\dot{X}_1$ (first approximation, used for damping) |
| 6 | $DX$ if IMDIS=1 |
==== Example ====
For instance, in the case of a 2D static coupled mechanical water-thermal-air flow analysis ([[:prepro#(1) Remark on NTANA|NTANA]]=5), the value of the nodal speed (ICONE=3) in the Y-direction (ISPAC=2) at node 1 (INP=1) is found in CONEC(1,2,3). Assuming the studied structure has a total of NUMNP=100 nodes and IMDIS=0, the dimensions of the CONEC matrix are CONEC(100, 5, 3).\\
The corresponding value of IPCON for *.ipn or *.ipc files is then: \\
ipcon=(icone-1)*nspac+ispac=(3-1)*5+2=12
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===== SIGVA =====
SIGVA contains the values of variables at integration points. The structure of SIGVA is the following:
* From 1 to NSIG*NPI: Stresses as defined in the element (refer to [[:elements|Elements]])
* From NSIG*NPI+1 to NSIG*NPI+NVAR*NPI: State variables as defined by each material/flow law (refer to [[:laws|Laws]])
__Order:__ \\
* SIGpi=1, ..., SIGpi=npi, Qpi=1, ..., Qpi=npi \\
* In SIG: SIGmeca, SIGflow \\
* In Q: Qmeca, Qflow