1. CRS7 - General cross section 1.1. Data group identifier NEW COMPonent CRS7 1.2. Component type identifier CMPTYP-ID TEMP ALFA CMPTYP-ID: character(8): Component type identifier TEMP : real: Temperature at which the specification applies Dummy in present version ALPHA: real: Thermal expansion coefficient \(\mathrm {[Temp^{-1}]}\) Dummy in present version Figure 1. General cross-section. Zloc, Yloc is the local/beam element. W,V is the principal axis in the cross-section area. 1.3. Mass YECC_MASS ZECC_MASS YECC_MASS: real: Mass center coordinate \(\mathrm {Y_m}\) in local element system \(\mathrm {[L]}\) ZECC_MASS: real: Mass center coordinate \(\mathrm {Z_m}\) in local element system \(\mathrm {[L]}\) AMS RGYR AMS : real: Mass per unit length \(\mathrm {[M/L]}\) RGYR: real: Radius of gyration about mass center \(\mathrm {(Y_m,Z_m)}\) \(\mathrm {[L]}\) Bouyancy and added mass contribution to the inertia forces will be applied at the specified mass center. 1.4. Buoyancy YECC_BUOY ZECC_BUOY YECC_BUOY: real: Buoyancy center Y-coordinate in local element system \(\mathrm {[L]}\) Dummy in present version. Bouyancy center set equal to mass center. ZECC_BUOY: real: Buoyancy center Z-coordinate in local element system \(\mathrm {[L]}\) Dummy in present version. Bouyancy center set equal to mass center. AE AI AE: real: External cross-sectional area \(\mathrm {[L^2]}\) Basis for calculation of buoyancy AI: real: Internal cross-sectional area \(\mathrm {[L^2]}\) Dummy in present version 1.5. Stiffness properties Only constant stiffness properties are allowed. 1.6. Area center and principal axes The area center is the cross-section point where the axial force acts through. The principal axes are formally determined from the requirement \(\int_AV\,W\,\,\mathrm {d}A=0\), where \(\mathrm {V}\) and \(\mathrm {W}\) denote the principal coordinates and \(\mathrm {A}\) is the cross-section area. The orientation of the principal axes is defined in terms of a positive X-rotation \(\mathrm {\theta }\) relative to the beam element YZ-coordinate system as shown in the figure General cross-section YECC_AREACENT ZECC_AREACENT THETA YECC_AREACENT: real: Area center coordinate \(\mathrm {Y_a}\) in beam element system \(\mathrm {[L]}\) ZECC_AREACENT: real: Area center coordinate \(\mathrm {Z_a}\) in beam element system \(\mathrm {[L]}\) THETA: real: Orientation \(\mathrm {\theta }\) of principal axes V and W [deg.]. See figure General cross-section. 1.7. Shear center The shear center represents the attack point of the shear forces. YECC_SHEARCENT ZECC_SHEARCENT YECC_SHEARCENT: real: Shear center coordinate \(\mathrm {Y_s}\) in beam element system \(\mathrm {[L]}\) ZECC_SHEARCENT: real: Shear center coordinate \(\mathrm {Z_s}\) in beam element system \(\mathrm {[L]}\) 1.8. Axial stiffness EA EA: real > 0: Axial stiffness \(\mathrm {[F]}\) 1.9. Bending stiffness The bending stiffness refers to the principal axes V and W, see figure General cross-section. EJV EJW EJV: real > 0: Bending stiffness about principal V-axis \(\mathrm {[FL^2]}\) EJW: real > 0: Bending stiffness about principal W-axis \(\mathrm {[FL^2]}\) 1.10. Shear stiffness The shear stiffness refers to the principal axes V and W, see figure General cross-section. GAsW GAsV GAsW: real: Shear stiffness in principal W-direction \(\mathrm {[F]}\) GAsV: real: Shear stiffness in principal V-direction \(\mathrm {[F]}\) The shear stiffness, GAsW and GAsV, are optional input parameters. Specified GAsW>0 and GAsV>0 will include shear deformation. 1.11. Torsion stiffness GT GT: real > 0: Torsion stiffness \(\mathrm {[FL^2/Radian]}\) For a circular cross-section the torsion stiffness is given by the polar moment of inertia. Note that this is not the case for non-circular cross-sections. 1.12. Bending-torsion geometric coupling This data group is optional. BTGC BTGC: character(4): bending-torsion coupling identifier. If the BTGC identifier is present, geometric coupling between torsion and bending is accounted for. 1.13. Damping specification Identical to input for cross-section type CRS2, see data group Damping specification for CRS2, except that the bending contributions are specified in the principal axis system and that only the damping option MATE is allowed. This means that the stiffness matrix used as basis for the Rayleigh damping includes the material stiffnesses only. The geometric stiffness matrix is not included as this would introduce damping of the rigid body motion for CRS7. The mass proportinal Rayleigh damping is applied in the local element system, not at the center of mass. Note that use of mass proportional damping is not recommended as this would introduce damping of the rigid body motions. 1.14. Hydrodynamic load type identification, One input line CHLOAD CHLOAD: character: = HYDR - Text to identify hydrodynamic coefficients Note: Required if non-Morison loads are to be specified Load type identification for CHLOAD=HYDR, One input line CHTYPE CHTYPE: character: Hydrodynamic load type = NONE: No hydrodynamic load coefficients = MORI: Slender element hydrodynamic coefficients Hydrodynamic force coefficients if CHTYPE=MORI CDX CDY CDZ CDTMOM AMX AMY AMZ AMTOR CDLX CDLY CDLZ SCFKN SCFKT CDX: real: Drag force coefficient for local x-direction \(\mathrm {[F/((L/T)^2\times L)]}\) CDY: real: Drag force coefficient for local y-direction \(\mathrm {[F/((L/T)^2\times L)]}\) CDZ: real: Drag force coefficient for local z-direction \(\mathrm {[F/((L/T)^2\times L)]}\) CDTMOM: real: Drag force coefficient for local x-rotation. Not used in present version. AMX: real: Added mass per length in x-direction \(\mathrm {[M/L]}\) AMY: real: Added mass per length in y-direction \(\mathrm {[M/L]}\) AMZ: real: Added mass per length in z-direction \(\mathrm {[M/L]}\) AMTOR: real: Added mass for local x-rotation \(\mathrm {[ML^2/L]}\) CDLX: real, default: 0: Linear drag force coefficients in local x-direction \(\mathrm {[F/((L/T)\times L)]}\) CDLY: real, default: 0: Linear drag force coefficients in local y-direction \(\mathrm {[F/((L/T)\times L)]}\) CDLZ: real, default: 0: Linear drag force coefficients in local z-direction \(\mathrm {[F/((L/T)\times L)]}\) SCFKN: real, default: 1: Scaling factor for the Froude-Krylov term in Morison’s equation in normal direction SCFKT: real, default: 1: Scaling factor for the Froude-Krylov term in Morison’s equation in tangential direction. Only the values 0.0 and 1.0 are permitted. The drag forces per unit length acting in the local coordinate system are computed as: \(\mathrm {F_x=CDX\times VRELX\times VRELX+CDLX\times VRELX}\) \(\mathrm {F_y=CDY\times VRELY\times VRELY+CDLY\times VRELY}\) \(\mathrm {F_z=CDZ\times VRELZ\times VRELZ+CDLZ\times VRELZ}\) where: \(\mathrm {CDX,CDY,CDZ}\): are the input quadratic drag force coefficients in local x, y and z-directions \(\mathrm {CDLX,CDLY,CDLZ}\): are the input linear drag force coefficients in local x, y and z-directions \(\mathrm {VRELX,VRELY,VRELZ}\): are relative water velocities in local x, y and z-directions The input quadratic drag force coefficients \(\mathrm {CDX}\), \(\mathrm {CDY}\) and \(\mathrm {CDZ}\) will normally be calculated as: \(\mathrm {CDX=\frac{1}{2}\rho S_{2D}C_{dx}}\) \(\mathrm {CDY=\frac{1}{2}\rho B_yC_{dy}}\) \(\mathrm {CDZ=\frac{1}{2}\rho B_zC_{dz}}\) where: \(\mathrm {\rho }\): water density \(\mathrm {S_{2D}}\): cross sectional wetted surface \(\mathrm {B_y,B_z}\): projected area per. unit length for flow in local y and z-direction, respectively \(\mathrm {C_{dx},C_{dy},C_{dz}}\): nondimensional drag coefficients in local x, y and z-directions, respectively The input added mass per. unit length \(\mathrm {AMX}\), \(\mathrm {AMY}\) and \(\mathrm {AMZ}\) can be calculated as: \(\mathrm {AMX=\rho AC_{mx}}\) \(\mathrm {AMY=\rho AC_{my}}\) \(\mathrm {AMZ=\rho AC_{mz}}\) where: \(\mathrm {\rho }\): water density \(\mathrm {A}\): cross sectional area \(\mathrm {C_{mx},C_{my},C_{mz}}\): nondimensional added mass coefficients in local x, y and z-directions, respectively 1.15. Aerodynamic load type identification, One optional input line CHLOAD CHLOAD: character: = WIND - Text to identify wind coefficients 1.16. Load type identification, One optional input line CHTYPE CHTYPE: character: Type of wind load coefficients = MORI: Morison-like loading, Drag term = AIRC: Air foil cross section to be specified (Not implemented) = AIRF: Air foil cross section, Refers to a air foil library file CHTYPE=MORI: Morison-like aerodynamic drag, One input line CDXAERO CDYAERO CDZAERO CDXAERO: real: Dimensional quadratic drag coefficient for local x-direction \(\mathrm {[F/((L/T)^2\times L)]}\) CDYAERO: real: Dimensional quadratic drag coefficient for local y-direction \(\mathrm {[F/((L/T)^2\times L)]}\) CDZAERO: real: Dimensional quadratic drag coefficient for local z-direction \(\mathrm {[F/((L/T)^2\times L)]}\) The drag forces per unit length acting in the local coordinate system are computed as: \(\mathrm {F_x=CDXAERO\times VRELX\times |VRELX|}\) \(\mathrm {F_y=CDYAERO\times VRELY\times \sqrt{VRELY^2+VRELZ^2}}\) \(\mathrm {F_z=CDZAERO\times VRELZ\times \sqrt{VRELY^2+VRELZ^2}}\) where: \(\mathrm {CDXAERO,CDYAERO,CDZAERO}\): are the input quadratic drag force coefficients in local x, y and z-directions \(\mathrm {VRELX,VRELY,VRELZ}\): are relative wind velocities in local x, y and z-directions The input quadratic drag force coefficients \(\mathrm {CDX}\), \(\mathrm {CDY}\) and \(\mathrm {CDZ}\) will normally be calculated as: \(\mathrm {CDXAERO=\frac{1}{2}\rho _{air}S_{2D}C_{dx}}\) \(\mathrm {CDYAERO=\frac{1}{2}\rho _{air}B_yC_{dy}}\) \(\mathrm {CDZAERO=\frac{1}{2}\rho _{air}B_zC_{dz}}\) where: \(\mathrm {\rho _{air}}\): air density \(\mathrm {S_{2D}}\): cross sectional surface area \(\mathrm {B_y,B_z}\): projected area per. unit length for flow in local y and z-direction, respectively \(\mathrm {C_{dx},C_{dy},C_{dz}}\): nondimensional drag coefficients in local x, y and z-directions, respectively If the component is part of a wind turbine tower line, only the CDY component is used for tower shadow computation. CHTYPE=AIRF: Coefficients on file. ID and chord length, One input line CHCOEF CHORDL YFC ZFC ROTFAX CHCOEF: character(32): Air foil coefficient identifier. Must be found on the air foil library file CHORDL: real: Chord length of foil section. \(\mathrm {[L]}\) It is used to scale the air foil load coefficients. YFC: real, default: 0: Y-coordinate of foil origin \(\mathrm {[L]}\) ZFC: real, default: 0: Z-coordinate of foil origin \(\mathrm {[L]}\) ROTFAX: real, default: 0: Inclination of foil system \(\mathrm {[deg]}\) The blade coordinate system and origin coincides with the elastic (local) \(\mathrm {(X_L,Y_L,Z_L)}\) coordinate system. The aerodynamic coordinate system \(\mathrm {(X_{AF},Y_{AF})}\) is located at (YFC,ZFC) referred to the local coordinate system, and is rotated about the blade x axis by the angle ROTFAX, as indicated in the figure below. The \(\mathrm {X_L}\) axis is pointing into the paper plane, while the \(\mathrm {Z_{AF}}\) is pointing out of plane. Note that the air foil coefficients has to be referred to the aerodynamic coordinate system as indicated by the corresponding angle of attack in the figure. For airfoil elements that are part of a wind turbine blade, the local \(\mathrm {X_L}\)-axis is pointing towards the blade tip. Note that suppliers of wind turbine blades normally give the foil twist relative to the the areodynamic coordinate system, i.e. as twist around the \(\mathrm {Z_{AF}}\) -axis. Definition of foil center and inclination of foil system in the local cross section (strength In coupled analysis, a SIMO wind type with IWITYP >= 10 must be used if the case contains elements with wind force coefficients that are not on the blades of a wind turbine. 1.17. Capacity parameter TB YCURMX ZCURMX TB: real: Tension capacity \(\mathrm {[F]}\) YCYRMX: real: Maximum curvature around local y-axis \(\mathrm {[1/L]}\) ZCURMX: real: Maximum curvature around local z-axis \(\mathrm {[1/L]}\) These parameters are dummy in the present version Partly submerged cross section Components