Evaluating the SEADYN Model: Mooring Dynamics Experiment Five
Abstract
The computer model of ocean cable structures, SEADYN was used to calculate the anchor-last deployment of the sixth mooring (experiment five) of the Mooring Dynamics Experiment (MDE) conducted in Hawaii waters in 1976. Comparisons are drawn with measurements of configuration and tension made during the deployment. The SEADYN configuration correlated well with the experimental data when an anchor drag coefficient of 0.78 was used. This value was precalculated to produce the terminal velocity experienced in the MDE. The MDE provided exceptionally detailed tension data at four points along the mooring. SEADYN reproduces the general features of these measurements with remarkable accuracy. The SEADYN tension traces include spurious oscillations that mask details of the tension history. These oscillations are believed to result from the omission of material damping in the SEADYN algorithm. Inclusion of hysteresis in the material stress-strain function is expected to remove the oscillations. Modeling the MDE mooring occurs in two steps. SEADYN is a general cable dynamics computer model, using the finite-element method. The SEADYN user is also modeler as he reduces the physical mooring to equivalent elements and spherical or cylindrical nodes. This requires considerable technical skills and intuition when, for example, the physical object at the node is a pile of sandbags on a pallet.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1980
- Accession Number
- ADA082165
Entities
People
- David B. Dillon