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*Winch |
 
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*Winch
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*Winch |
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To define winch elements.
Refer to Winch Elements for further information on this feature.
Data is specified in blocks of two lines repeated as many times as necessary to define the properties of each winch element set. The format used depends on the type of analysis being carried out.
In the case of a static analysis the following block is used:
SET=Element Set
LENGTH=Added Length
In the case of a time domain dynamic or quasi-static analysis, either of the following two blocks can be used:
For a standard velocity profile:
SET=Element Set
Winching Velocity, Ramp-up Start, Ramp-up End, Ramp-down Start, Ramp-down End
For winch payout based on a timetrace file:
SET=Element Set
FILE=File Name
The block of data used must be in accordance with the type of analysis being carried out. So the first block can only be used for static analyses. Likewise the second or third blocks can only be used for time domain dynamic or quasi-static analyses. The winching time sequence must be specified in ascending order. This keyword is not relevant for frequency domain dynamic analysis.
The Added Length is the length by which by the winch element set is to expand or contract (the value may be positive or negative) during the course of the static analysis.
File Name should include the entire path of the winch time history file including its extension. If the file name or any part of its path contains spaces then it should be enclosed in double quotation marks.
Input: |
Description |
Set Name: |
The element set to which the winch element properties are to be assigned. |
Added Length: |
The length by which by the winch element set is to expand or contract (the value may be positive or negative) during the course of an analysis. |
Input: |
Description |
Set Name: |
The element set to which the winch element properties are to be assigned. |
Velocity: |
The maximum pay-out (or reel-in) velocity of the winch elements. |
Ramp-up Start: |
The start time of ramp-up in the winching time sequence. |
Ramp-up End: |
The end time of ramp-up in the winching time sequence. |
Ramp-down Start: |
The start time of ramp-down in the winching time sequence. |
Ramp-down End: |
The end time of ramp-down in the winching time sequence. |
Input: |
Description |
Set Name: |
The element set to which the winch element properties are to be assigned. |
File Name: |
The name of the file which contains the time history of winch element payout. See note (b). |
(a) Winch elements are typically normal beam elements, and are defined in the same manner as all beam elements, but are unique in that their lengths may be dynamically modified during an analysis. Refer to Winch Elements for further information on this feature.
(b) The winch timetrace file consists of rows of time and winch length data. The first value on each line is the solution time and the second is the associated change in length of the winch set from the original length of the set. The two values on each line should be separated by a space(s) and/or a comma. Blank lines and comment lines (lines where "C" is the first character on the line) will be ignored. Rows must be specified in ascending time order and cubic spline interpolation is used to calculate winch lengths for solution times between those specified in the winch timetrace file. An example of the winch timetrace file format is shown below. Say, for a winch set with original length of 10m, the following file describes a scenario where the winch set length remains at 10m until it ramps up to 15m (original + change) from 20s.
C Time Length Change
1, 0.0
10, 0.0
20, 5.0
30, 5.0
40, 5.0