Learning Forum

[alvin.120300073]

Hello, how to determine value anticipated database poiny to input positive and negative dZ range expected connection point vertical motion on cable propertiez

[Shuangxing Du]

Directly solving the catenary cable equations for the static nonlinear catenary line with up to 10 sections at each time step in the time domain analysis or at each iterative step in the equilibrium calculation is time consuming.  Aqwa creates the nonlinear catenary cable database before the simulation at each time or iterative step, then the database is used to determine the cable's responses at each time/iterative step by the interpolation approach. As shown in Aqwa user's manual, section 5.8.1, for a cable attached between a fixed point (anchor) and a connection point on structure, this database has  Number of Vertical Partitions (z-levels) and Number of X Coordinates (horizontal partitions). As shown below, the distance (d1) from the highest anticipated database point z-level (the highest z-level which the connection point may go during the analysis) to the connection point definition position z-level should be input as Positive dZ; and the distance (d2) from the connection point definition position z-level to the lowest anticipated database point z-level (the lowest z-level which the connection point may go during the analysis) should be input as Negative dZ. Both d1 and d2 are positive, as they are the distances between the above-mentioned z-levels.

You may need to estimate the most probable highest relative vertical shifting distance between the actual position of the connection point and its definition poition (for example 3 meters), then set d1 to be a value being larger than it (for example 4~6 meters). Silimar approach applies for setting d2. 

[alvin.120300073]

Tahnk you, this is easy for me to understand