Section 6 Direct Strength Assessment

601. General

This Guidance deals with procedure of direct structural analysis that is composed of structural model- ing, stress calculating, yielding check and buckling check for the primary supporting members of hull.

602. Direct Global Structural Analysis

1. General (1)Application

(A) This Guidance provides overall procedures to be used in the global structural analysis with

direct transfer of loads from hydrodynamic and stochastic analysis for the purpose of struc-

tural safety assurance.

(B) The design of the structure is to be in accordance with Pt 3, Ch 3 of Rules for the Classification of Steel Ships regardless of the structural analysis according to this guid-

ance, and the results of the direct global structural analyses cannot be used to reduce the basic scantlings based on the Rules.

(C)t is recommended to use the probability years in intended site for design loads.

(D) The seakeeping and hydrodynamic load

gram recognized by the Society based method. The non-linear effects should be

level equivalent to a return period of at least 100

analysis is to be carried out using computer pro- on linear 2D Strip method or linear 3D panel considered if these effects are regarded to be im-

portant after initial evaluation of the hull shape.

(E) The structural analysis is to be carried out using computer program which can consider the

effects of bending deformation, shear deformation, axial deformation and torsional deformation.

(2) Documentation

The reports including drawings, structural and hydrodynamic model, mass model, assumption and theory used in analysis, results of loads calculation, results of structural analysis etc. should be presented to the Society for approval of the direct global structural analysis in accordance with this Guidance.

(3) The flow chart of the direct global structural analysis is shown in Fig 5.1.

2. Structural analysis and acceptance criteria

(1) Structural analysis

(A) The structural analysis is to be carried out with the Finite Element Method.

(B) An approved analysis program having adequate accuracy should be used. If deemed neces- sary, documents related to systems used in the analysis and documents for confirming the

accuracy may be required to be submitted to the Society.

(2) Acceptance criteria

The results of global structural analysis is to be assessed for the failure mode of yielding ac-

cording to the allowable stress as specified in Pt 5, Ch5, of Rules for the Guidance for Floating Production Units.

603. Additional Application

Other various matters on the major element modeling, stress calculations, yield strength, buckling

strength assessment and evaluation process

for the Classification of steel ships.

of hull structure are to be as specified in Pt

3 of

Rules

Fig 5.1 Flow chart of the direct global structural analysis