bionic (1) gmtflexure.1gmt.gz

NAME

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

SYNOPSIS

       gmtflexure  -Drm/rl[/ri]/rw -ETe[u]|D|file [  -A[l|r][/args] ] [  -CpPoisson ] [  -CyYoung ] [  -Fforce ]
       [  -Qargs] [  -S ] [  -Twfile] [  -V[level] ] [  -Wwd] [  -Zzm] [ -bibinary ] [ -dnodata ] [ -eregexp ] [
       -hheaders ] [ -iflags ] [ -oflags ]

       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.

       -d[i|o]nodata (more …)
              Replace input columns that equal nodata with NaN and do the reverse on output.

       -e[~]”pattern” | -e[~]/regexp/[i] (more …)
              Only accept data records that match the given pattern.

       -h[i|o][n][+c][+d][+rremark][+rtitle] (more …)
              Skip or produce header record(s).

       -icols[+l][+sscale][+ooffset][,…] (more …)
              Select input columns and transformations (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 just use -).

       -+ 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 all options, then exits.

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, grdflexure, grdmath

COPYRIGHT

       2018, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe