Post-Processing Joints - Ultramarine.com Post-Processing Joints

Structural Post-Processing results for joints are obtained with the command: 


     JOINT_POST, TYPE(1), ...., TYPE(i)  -OPTIONS

where TYPE(i) must be chosen from DISPLACEMENT, CODE_CHECK, S_FATIGUE, CRUSH, COUNT, or FATIGUE, and the available options are: 



     -NODE, :NODE_SEL(1), :NODE_SEL(2), :NODE_SEL(3), :NODE_SEL(4)


     -ELEMENT, :ELE_SEL

     -LOAD, :LSEL

     -STANDARD, L(1), T(1), ..... L(n), T(n)

     -SUMMARY, L(1), T(1), ..... L(n), T(n)

     -DETAIL

     -REPORT, YES/NO

     -FILE, YES/NO

     -LOCAL, YES/NO


     -CLASS, :CLS_SEL

     -CODE, TYPE, CCAT, EDITION

     -SN, CURVE, TYPE, S(1), N(1), ..... S(n), N(n)

     -THICK_SN, TO, POWER, MAXCOR, YES/NO

     -LIFE, DLIFE

     -WL_RANGE, -ELEV, +ELEV

     -DURATION, :DURATION_SEL

     -S_BINS, S(1), S(2), ......, S(n)

     -CSRV_JFAT, YES/NO

     -CLS_MEAN, YES/NO

Here, joints which match :NODE_SEL(1) will be considered. Further, if the class of the chord does not match :CLS_SEL, the joint will not be considered. Only braces with end nodes which match both :NODE_SEL(1) and :NODE_SEL(2), names which match :ELE_SEL, and classes which match :CLS_SEL will be considered. Results will only be considered for cases which match :LSEL which is defined with the -LOAD option. For FATIGUE, all durations which match :DURATION_SEL defined via the -DURATION option will be considered. If no values are given for TYPE(i), then results for all TYPEs will be produced.

Here, a TYPE of

The extent of the reports except for DISPLACEMENT and COUNT is controlled by which of the three report types were selected and the report limits. With a -STANDARD or -SUMMARY report, L(i) and T(i) are used to specify a range of code unity values for which a given report will be printed. For a TYPE of FATIGUE, the value is the CDR, and for all others it is the code unity value. One can specify as many ranges as he desires, or he can omit all data following the option. If no ranges are specified, one report for all ranges of value will be printed. An option of -STANDARD will result in a report of the results for the maximum unity ratio over all selected load cases for each member selected. If one specifies an option of -SUMMARY, this report will be reduced to the results for only the selected element in each class which has the greatest unity ratio. Finally, if one specifies -DETAIL as an option, the original report will be expanded to include checks of all members for all selected load cases at all load points. Notice that -DETAIL, -STANDARD, and -SUMMARY may all be used on the same command to produce reports of all three types. If no options are specified, -STANDARD is assumed.

For a TYPE of DISPLACEMENT, three additional options are available: -REPORT, -FILE, and -LOCAL. The first two of these options are used to control whether or not the results are written to a post-processing file, or to the standard output file. The default is to write them only to the output file. If -FILE YES is specified, then the results will be written to both places. If -FILE YES -REPORT NO is specified, then the results will only be written to the post-processing file. By default, the displacements are reported in the body part system. If one uses the option -LOCAL NO, then the displacements will be reported in the "current" global system. Notice, since the structural results can come from many different processes at many different events, the current global system may not be a good system in which to view the deflections produced at events with a different configuration.

The type of unity ratio which will be computed for types of CRUSH and CODE_CHECK depends upon the last -CODE option. The type of code which will be used depends upon the last -CODE option. Here, TYPE may be either AISC, API, NORSOK, or ISO. The value CCAT defines the class of check for AISC or API type checks. It should be omitted for ISO or NORSOK type checks and it must be either WS or LRFD for AISC or API checks. If it is omitted for these checks, WS will be assumed. If one wishes to use an LRFD check, it is his responsibility to build load cases which include the proper multipliers. This option is remembered between BEAM code checks and JOINT checks. Thus, if one has previously used the -CODE option he need not be re-issued. EDITION defines the edition of RP2A which will be used checked for the check. If it is OLD, then the first supplement of the 21st edition will be used otherwise the "new" method will be used. If one wishes to use an LRFD check, it is his responsibility to build load cases which include the proper multipliers.

For a type of CRUSH the results computed consist of the force and moment in the chord due to the braces, stresses in the chord as a function of angle around the chord, and a unity ratio. The unity ratio is the larger of the stress unity based on an allowable of .6Fy and the shear unity based on an allowable of .4Fy. The stress reported is the stress which produced the unity ratio. This angle is measured clockwise from the first brace. For the options -STANDARD and -SUMMARY only the results at the angle which corresponds to the highest unity check are reported, while if the option -DETAIL is selected, one will receive results for all 36 angles around the joint. The stresses are computed by superimposing stresses due to each brace load and using the formulae for circular rings in Roark's Formulas for Stress and Strain, Sixth Edition. Here, the length of the ring is taken to be the "effective length" of the joint according to API-RP2A. For each brace, two cases are added: first, a uniform load distributed over a segment of the chord equal the brace diameter, and second a shear around the circumference of the chord.

The -SN, -F_STRESS, and -THICK_SN options are used to define the SN curve which will be used in computing the cumulative damage ratios, and are discussed in detail in the section on Defining and Associating SN curves. The two options -LIFE and -WL_RANGE are applicable only to a TYPE of S_FATIGUE. Here, DLIFE is the design life, which must be either 20 or 40. The two parameters -ELEV and +ELEV define the distances below and above the water surface between which members will be considered to be "waterline" members. -ELEV should be a negative number and +ELEV should be a positive one.

The -DURATION option is applicable only to types of FATIGUE and COUNT and tells MOSES to use only the sets of duration data which match :DURATION_SEL. The -S_BINS option is applicable only to a type of COUNT. It is used to define a set of "bins" by stress range to accumulate the cycle data. Here, S(1) (ksi or mpa) marks the "top" of the first bin, S(2) the top of the second bin, etc. The stresses which are accumulated include the stress concentration factor, but not any stress concentration due to an SN curve.

The final options are applicable only to a TYPE of FATIGUE. Also with FATIGUE, the meaning of -DETAIL, -STANDARD, and -SUMMARY is a bit different. -DETAIL is ignored. For -STANDARD, one receives the total CDRs for all computed points where the maximum of the CDRs lie between L(i) and T(i). Finally, for -SUMMARY, one only receives a report of the maximum CDR for all of the computed points which lie in the specified range. The -CSRV_JFAT option controls the action taken with the brace/chord SCFs. MOSES computes CDRs at eight points around the intersection of the brace with the chord. If YES/NO is NO, both the brace and chord side are considered, and sixteen CDRs will be computed. If, however, YES/NO is YES, then the maximum of the two SCF values is taken and a CDR is computed for these values of SCF at the eight points. A value of YES will yield slightly conservative values and significantly reduce the computational effort. The -CLS_MEAN option controls the manner in which the joint is classified if the previous option is not used. IF YES/NO is YES, then the joint will be classified using the frequency mean load case; otherwise, MOSES will compute a new joint classification (and hence SCF) for each force response operator.