xenial (1) gmtflexure.1gmt.gz

NAME

       gmtflexure - Compute flexural deformation of 2-D loads, forces, bending and moments

SYNOPSIS

       gmtflexure rm/rl[/ri]/rw -ETe[u]|D|file [ [l|r][/args] ] [ pPoisson ] [ yYoung ] [ force ] [ args] [  ] [
       wfile] [ [level] ] [ wd] [ zm] [ -bi<binary> ] [ -i<flags> ] [ -o<flags> ]

       Note: No space is allowed between the option flag and the associated arguments.

DESCRIPTION

       gmtflexure computes the flexural response to 2-D loads using a range of user-selectable options, such  as
       boundary  conditions,  pre-existing  deformations,  variable rigidity and restoring force, and more.  The
       solutions are obtained using finite difference approximations to the differential equations.

REQUIRED ARGUMENTS

       -Drm/rl[/ri]/rw
              Sets density for mantle, load, infill (optionally, otherwise it  is  assumed  to  equal  the  load
              density), and water.  If ri is not given then it defaults to rl.

       -ETe[u]|D|file
              Sets  the  elastic  plate thickness (in meter); append k for km.  If the elastic thickness exceeds
              1e10 it will be interpreted as a flexural rigidity D instead (by default D is  computed  from  Te,
              Young's  modulus,  and  Poisson's  ratio; see -C to change these values).  Alternatively, supply a
              file with variable plate thicknesses or rigidities.  The file must be co-registered with any  file
              given via -Q.

OPTIONAL ARGUMENTS

       -A[l|r]bc[/args]
              Sets  the  boundary conditions at the left and right boundary.  The bc can be one of four codes: 0
              selects the infinity condition, were both the deflection and its slope are set to zero.  1 selects
              the  periodic  condition  where  both the first and third derivatives of the deflection are set to
              zero.  2 selects the clamped condition where args (if given) sets the deflection  value  [0]  (and
              its  first  derivative  is set to zero), while 3 selects the free condition where args is given as
              moment/force which specify the end bending moment and vertical shear force [0/0].   Use  SI  units
              for any optional arguments.

       -CpPoisson
              Change the current value of Poisson's ratio [0.25].

       -CyYoung
              Change the current value of Young's modulus [7.0e10 N/m^2].

       -Fforce]
              Set a constant horizontal in-plane force, in Pa m [0]

       -Qn|q|t[args]
              Sets  the  vertical  load  specification.  Choose among these three options: -Qn means there is no
              input load file and that any deformation is simply driven by the boundary conditions set  via  -A.
              If  no rigidity or elastic thickness file is given via -E then you must also append min/max/inc to
              initiate the locations used for the calculations.  Append + to  inc  to  indicate  the  number  of
              points  instead.   -Qq[loadfile]  is  a  file  (or stdin if not given) with (x,load in Pa) for all
              equidistant data locations.  Finally, -Qt[topofile] is a file (or stdin if not given) with (x,load
              in m or km, positive up); see -M for topography unit used [m].

       -S     Compute  the  curvature  along  with  the  deflections and report them via the third output column
              [none].

       -Twfile
              Supply a file with pre-existing deformations [undeformed surface].

       -Wwd   Specify water depth in m; append k for km.  Must be positive [0].  Any subaerial  topography  will
              be scaled via the densities set in -D to compensate for the larger density contrast with air.

       -Zzm   Specify  reference  depth  to flexed surface in m; append k for km.  Must be positive [0].  We add
              this value to the flexed surface before output.

       -V[level] (more ...)
              Select verbosity level [c].

       -bi[ncols][t] (more ...)
              Select native binary input.

       -icols[l][sscale][ooffset][,...] (more ...)
              Select input columns (0 is first column).

       -ocols[,...] (more ...)
              Select output columns (0 is first column).

       -^ or just -
              Print a short message about the syntax of the command, then exits (NOTE: on Windows use just -).

       -+ or just +
              Print an extensive usage (help) message, including the explanation of any  module-specific  option
              (but not the GMT common options), then exits.

       -? or no arguments
              Print a complete usage (help) message, including the explanation of options, then exits.

       --version
              Print GMT version and exit.

       --show-datadir
              Print full path to GMT share directory and exit.

NOTE ON UNITS

       The  -M  option  controls  the  units  used in all input and output files.  However, this option does not
       control values given on the command line to the -E, -W, and -Z options.   These  are  assumed  to  be  in
       meters unless an optional k for km is appended.

PLATE FLEXURE NOTES

       We  solve  for  plate  flexure using a finite difference approach. This method can accommodate situations
       such as variable rigidity, restoring force that depends on the deflection  being  positive  or  negative,
       pre-existing deformation, and different boundary conditions.

EXAMPLES

       To  compute  elastic  plate  flexure  from  the topography load in topo.txt, for a 10 km thick plate with
       typical densities, try

              gmt flexure -Qttopo.txt -E10k -D2700/3300/1035 > flex.txt

REFERENCES

SEE ALSO

       gmt, gravfft grdflexuregrdmath

COPYRIGHT

       2015, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe