Description
What this Excel App does
This excel app calculates the accelerations on equipment being carried by a jack-up as per ASD/WSD Default Motion Criteria (DNVGL-ST-N001, Table 11-1)
a. Accelerations due to motions: It calculates the accelerations due to the jack-up’s roll, pitch, and heave, depending on the size of the equipment and size of the jack-up, in accordance with DNVGL Guidelines
b. Wind Loads: It also calculates the wind loads coming onto the equipment in accordance with the ABS Rules for MODU
b. Final Accelerations: It also calculates the final accelerations due to motions + wind loads and reports the accelerations in Longitudinal, Transverse, and Vertical Directions in terms of ‘g’
Directions for Use
1. All the cells which require input are in the Worksheet ‘Inputs’ and have a blue background. Please fill only input cells, i.e., ones with a blue background. Leave the other cells untouched, as they are output cells
2. Fill in the inputs in the Worksheet ‘Inputs’
3. Once the ‘Inputs’ sheet is completed, accelerations will be automatically calculated in the Worksheets ‘Motion Forces’ and ‘Windloads’ and reported in the ‘Final Accelerations’ worksheet.
Assumptions
1. Cargo areas are taken considering it as a rectangular box
2. The standard motion criteria of DNVGL-ST-N001 Sec 11.7.2 are assumed to apply
3. Only to be used for jack-ups
4. The equipment’s own moment of inertia is ignored. Equipment is considered as a point mass. Thus this spreadsheet should be used carefully with equipment of big sizes which may have a substantial self moment of inertia
5. Phase differences between forces are ignored. This leads to conservative results
6. The forces are resolved in the following directions: Vertical – perpendicular to the deck. Transverse- parallel to the deck in the transverse direction, Longitudinal – parallel to deck in the longitudinal direction
References
1. DNVGL-ST-N001 2016, Sec 11.7.2
2. ABS RULES FOR BUILDING AND CLASSING MOBILE OFFSHORE DRILLING UNITS, 2020, C 3-1-3/1.3.2
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