Page 70 - Wire Rope News & Sling Technology - August 2019
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INVENTOR’S CORNER
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         input from a rope data sensor processor 30 and lifting system
         processor and database 28. Overall processor and database
         32 can also receive input at external statistical data input 36.
         This input data can be, for example, data from historic use of
         rope 16 or another rope and/or data from tests performed on
         rope 16 or another rope. Interface 34 is connected to overall
         processor and database 32, and can be used to control com-
         puter system 36 and rope monitoring and analysis system 10.
         Interface 34 can be used for various tasks including, control-
         ling rope 16; monitoring rope 16 in real-time; predict main-
         tenance and/or replacement schedules for a portion or all of
         rope  16;  analyzing  data  and/or  generating  reports  on  data
         collected. Computer system 26 can receive and/or store data
         regarding rope 16 per section of rope 16 for the entire work-  Figure 22: Example data output plot from the rope monitoring and
         ing length, for one or more particular sections of rope 16 (for   analysis system.
         example, heavily used sections), and/or for any number of sec-  nance or replacement schedules of some or all of rope 16.
         tions for which there is useful data.                Additionally, data can be compiled and stored for future use
           Rope monitoring and analysis system 10, through the use   in prediction of condition, maintenance and/or replacement
         of a rope data sensor 18, a number of rope usage sensors 22,   schedules in relation to use and/or usage events for one or
         24, a position measurement device 20 and computer system   more sections of rope 16 or other ropes.
         26 allow for accurate analysis and monitoring of rope 16 for   Figure 22 shows an example data output plot 39 from the
         a real-time indication of the condition of one or more sections   rope monitoring and analysis system 10, and includes lifting
         of rope 16 at any point in time. In past offshore and onshore   system operational data algorithm output 40 and cross-sec-
         operations using multi-strand ropes, the ropes were typically   tional area output 42. Along the x-axis is the rope length or
         visually inspected or a measurement of rope cross-sectional   sectional displacement, thus correlating measurements (and
         area was taken at a specific point in time. This measurement   algorithm output from sensor data) to a section of rope 16.
         could be taken using a device through which the rope passed,   Cross-sectional area output 42 shows a measurement of
         and the device was able to detect weakening and/or defects   the cross-sectional area of rope 16 at each point along rope
         based on measurements of the rope passing through the de-  16. This data is from rope data sensor 18, and gives a mea-
         vice. This single data point inspection (correlated with classi-  surement of the cross-sectional area and therefore overall
         fication society guidelines to guarantee safety of the systems)   strength of each point along rope 16.
         was then used to predict when a rope needed replacement.   System operational data algorithm output 40 is formed by
         This past method often resulted in prematurely replacing the   collecting data regarding tension, bends and temperature of
         rope as a conservative measure to prevent catastrophic fail-  rope 16 at each point. This is collected by one or more usage
         ure, and lead to high materials and replacement costs.  sensors, depicted in figure 21 as tension sensor 22 and tem-
           By using rope monitoring and analysis system 10, continu-  perature sensor 24. In other reports, data regarding tension,
         ous real-time data collection of a physical property of rope   bending, temperature or any other property measured could be
         16 can be taken and correlated with data continuously col-  graphed separately on plot 39. The algorithm to integrate the
         lected regarding usage of the rope 16 and/or environmental   data and form output 40 can be developed using data collected
         conditions during usage of rope 16 to give a real-time indica-  by system 10, historic data stored regarding rope 16 and/or
         tion of the condition of a section of the rope 16 at any point   other similar ropes and/or data input into computer system 26.
         in time. Additional input regarding other statistical and/or   By plotting out cross-sectional area and operational or us-
         test data could also be contributed if desired. The data in   age data against length of rope 16, a correlation between us-
         computer system 26 can then be used to extend the life of   age events and rope cross-sectional area can be seen, for ex-
         the rope 16, maintain safety during operations using rope   ample, at point A along rope’s length, it can be seen that there
         16 and decrease materials and replacement costs by being   is a high portion on lifting system operation data output 40.
         able to indicate when replacement of some or all of rope 16 is   This could correspond to a section of the rope that had high
         needed. The data and correlation can also be used to predict   tension forces and/or high temperatures. For example, this
         wire condition, the useful life of the rope 16, and mainte-  could correlate to a zone when load 17 is about to touch down
                                                              to seabed for a particular operation. At this point, AHC sys-
                                                              tem 14 typically works very hard to ensure a smooth transi-
                                                              tion for load 17 touchdown. This can result in a high tempera-
                                                              ture and a great deal of tension and/or bending at that point
                                                              of rope 16. As can be seen from the graph of cross-sectional
                                                              area 42, there is a dip in the cross-sectional area at point A.
                                                              Thus, one or more strands of rope 16 may have snapped at
                                                              this  point  due  to  stresses  from  operations.  This  could  be  a
                                                              point where rope 16 needs replacement immediately or in a
                                                              short time period based on comparison with a threshold point
                                                              for cross-sectional area that the rope 16 must maintain to be
                                                              in a safe-condition. Additionally, this data could tell a user to
                                                              avoid this section of rope when other intense operations are
                                                              being carried out and try to concentrate any future intense
         Figure 21: Schematically illustrates an example rope monitoring and   operations on areas of the rope 16 that have a higher cross-
         analysis system.                                     sectional area as shown by plot 42.  WRN
         70     Wire Rope News & Sling Technology   August 2019
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