Section 4 Boundary conditions
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules for the Classification of Trimarans, July 2022 - Volume 4 Direct Calculation Procedure - Part 1 Direct Calculation Procedure - Chapter 2 Structural Strength Analysis and Verification - Section 4 Boundary conditions

Section 4 Boundary conditions

Parent topic: Chapter 2 Structural Strength Analysis and Verification

4.1 General

4.1.1 The load cases specified in Vol 4, Pt 1, Ch 2, 3 Load cases are to use the boundary conditions described in Vol 4, Pt 1, Ch 2, 4.2 Application.

4.1.2 The boundary conditions described in this Section are preferred. However, alternative equivalent boundary conditions may be used.

4.1.3 Care is to be taken that, within practicable limits, there is no net imbalance of load or moment in any of the six degrees of freedom.

4.1.4 If spring type restraints are used, spring stiffnesses are to be small, equivalent to 10 N/m.

4.1.5 Care is to be taken to ensure that the FE model is not over constrained.

4.1.6 These boundary conditions are also applicable to the loads calculated using the load calculation procedure in Vol 4, Pt 1, Ch 3 Load Development.

4.2 Application

4.2.1 All load cases are to have the boundary conditions described in Table 2.4.1 Boundary conditions for all load cases and Figure 2.4.1 Boundary conditions for all load cases.

Table 2.4.1 Boundary conditions for all load cases

Location Boundary conditions
At or near the neutral axis at the forward and aft ends of the ship
At a bulkhead near to the mid-length of the ship:
At a point on the deck and a point on the keel
At the keel of each of the side hulls

Figure 2.4.1 Boundary conditions for all load cases
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