Iranian Classification Society Rules

Section 4 Hull Girder Strength

401. Application

1. The hull girder strength of yacht, constructed in aluminium alloy, is to be in accordance with Ch 3, Sec 4. The material factor is to be in accordance with the Guidance relating to the Rules.

2. Material factor ( ) is to be as follows Table 3.4.1 thou. 3.4.4 and others than as following formula;

below are to be

: yield stress (N m m , proof load with 0.2 % permanent deformation) not to be taken is

Table 3.4.1 Factor

for Wrought Aluminium Alloy Plates

mm t

Grade

Temper condition

A 5052 P

H32 H34

1.64

1.45

A 5154A P

O, H111

2.86

A 5454 P

H32 H34

1.37

1.27

A 5086 P

H116, H32 H34

1.25

1.14

A 5083 P

H116, H321

1.12

(Remarks)

For temper condition

and

H111,

the

factor is

taken

from

Table

3.4.4

Table 3.4.2 Factor

for Aluminium Alloy Extruded Shapes ( Note : when the main loading

direction is longitudinal to the extrusion ) mm t

Grade	Temper condition
A 6061 S	T5/T6	1.32
A 6005A S	T5/T6	1.32
A 6082 S	T5/T6	1.11

Table 3.4.3 Factor

for Aluminium Alloy Extruded Shapes ( Note : when the main loading

direction is transverse to the extrusion ) mm t

Grade	Temper condition
A 6061 S	T5/T6	1.41
A 6005A S	T5/T6 6≤ t ≤10 10≤ t ≤25	1.32 1.49
A 6082 S	T5/T6	1.18

Table 3.4.4 Factor

in the Welded Condition

Grade	Temper condition	Welding consumables
A 5052	O, H111, H32, H34	A 5356 BY/WY	3.70
A 5154A	O, H111	A5356- A5183BY/WY	2.86
A 5454	O, H111, H32, H34	A5356- A5183BY/WY	2.86
A 5086	O, H111, H116, H32, H34	A5356- A5183BY/WY	2.38
A 5083	H116, H321, H116, H321	A 5356 BY/WY A 5183 BY/WY	1.89 1.67
A 6061	T5/T6	A5356- A5183BY/WY	2.08
A 6005A	T5/T6	A5356- A5183BY/WY	2.08
A6082	T5/T6	A5356- A5183BY/WY	2.08

402. Additional requirements

1. Where the forebody parts are transversely framed, be checked the following formula.

the axial force, defined in Ch 2, 401. 6, is to

∆ kN

: as defined in Ch 2, 401. 6.

The distribution of stresses will depend on instantaneous forward tion of cargo.

immersion and on loca-

2. Bottom structure in way of thrust bearings may need a check for the increased thrust when yacht is retarted by a crest in front.

3. Allowable axial stress and associated shear stresses are to be related to the stresses already existing in the region.

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