Common Structural Rules - Common Structural Rules for Bulk Carriers and Oil Tankers, January 2019 - Part 1 General Hull Requirements - Chapter 4 Loads - Section 3 Ship Motions and Accelerations - 3 Accelerations at any Position
3 Accelerations at any Position
3.1 General
3.1.1 The accelerations used to derive the inertial loads at any position are defined with respect to the ship fixed coordinate system. Hence the acceleration values defined in [3.2] and [3.3] include the gravitational acceleration components due to the instantaneous roll and pitch angles.
3.1.2 The accelerations to be applied for the dynamic load cases defined in Ch 4, Sec 2 are given in [3.2].
3.1.3 The envelope accelerations as defined in [3.3] are provided for advisory purposes and may be used for other design purpose when the maximum design acceleration values are required, for example, crane foundations, machinery foundations, etc.
3.2 Accelerations for dynamic load cases
3.2.1 General
The accelerations to be applied for the dynamic load cases defined in Ch 4, Sec 2 are given in [3.2.2] to [3.2.4].
3.2.2 Longitudinal acceleration
The longitudinal acceleration at any position for each dynamic load case, in m/s2, is to be taken as:
3.2.3 Transverse acceleration
The transverse acceleration at any position for each dynamic load case, in m/s2, is to be taken as:
3.2.4 Vertical acceleration
The vertical acceleration at any position for each dynamic load case, in m/s2, is to be taken as:
3.3 Envelope accelerations
3.3.1 Longitudinal acceleration
The envelope longitudinal acceleration, ax-env, in m/s2, at any position, is to be taken as:
where:
- apitch – x = apitch (z – R)
3.3.2 Transverse acceleration
The envelope transverse acceleration, ay-env, in m/s2, at any position, is to be taken as:
where:
- aroll – y = aroll (z – R)
3.3.3 Vertical acceleration
The envelope vertical acceleration, az-env, in m/s2, at any position, is to be taken as:
where:
- apitch – z = apitch (x – 0.45L)
- aroll – z = aroll y
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