Iranian Classification Society Rules

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Section 3 Shell Laminates for Midship Part


301. Side Shell Laminates of Single Skin Construction

The thickness of side shell laminates of single skin construction is not to be less than obtained from the following formula :


ᾼᾚ Ņ ÌJĊΡ̓Üᾘ Ñ LǾLĪĴÃ NmmŃ


where,

Ċ : Spacing of frames (m )


302. Bottom Shell Laminates of Single Skin Construction

The thickness of bottom shell laminates of single skin construction is not to be less than obtained from the following formula :


ᾼᾚ Ņ ÌJǾKĊΡ̓Üᾘ Ñ LǾLĪĴÃ NmmŃ


where,

Ċ : Spacing of frames (m )


303. Shell Laminates of Sandwich Construction


1. The aggregated thickness of inner layer, outer layer and core of sandwich construction is not to be less than obtained from the following formulae, whichever is greater :


ᾼÌ Ņ ǼÌĊNᾘÑ LǾLĪĴÃŃ Nmm Ń

image


ᾼÌ Ņ ǼĪᾼᾚ Nmm Ń


where,

ᾼᾚ : Thickness in case of single skin construction specified in 301. or 302. (mm ).

Ċ : Spacing of frames (m ).


ǼÌ : Coefficient obtained from the following formula :

ǼĮ

Üſſi

ᾍ


ſſiᾍ : Shearing strength of sandwich laminates obtained from the test specified in Ch 3,

Sec 28 of Guidance Approval, Etc. or the (NÕmm Ī)

for Approval of Manufacturing Process and Type

result for related test among Ch 3, 206. of this rules.

ǼĪ and ǼĮ : As given in Table 6.1. For the intermediate values of ft and ƒ, ǼĪ and ǼĮ are to be obtained by linear interpolation.


Table 6.1 Values of ǼĪ and ǼĮ


ƒ

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0


ǼĪ

ft=0.8

1.62

1.42

1.31

1.24

1.20

1.16

1.14

1.12

1.10

ft=1.0

1.54

1.36

1.25

1.19

1.15

1.12

1.10

1.08

1.07

ǼĮ

2.18

2.26

2.33

2.40

2.46

2.52

2.57

2.62

2.67

Where,

ft : The thickness of outer layer or inner layer of FRP, whichever is the divided by the greater thickness.

ƒ : The sum of the thickness of outer layer and inner layer of FRP divided by the thickness of core.


2. The respective thickness of inner layer and outer layer of shell laminate of sandwich construction is not, notwithstanding the requirements in the preceding 1, to be less than obtained from the follow- ing formula. In no case, however, is it to be less than 2.4 mm :


Ĩ

ᾼ Ņ ĮǾĴΡ̓Į ÜǼ Ċ ĨNᾘ Ñ LǾLĪĴÃ ŃĨ Nmm Ń


where,

Ċ : Spacing of frames (m ).


ǼĨ : Coefficient obtained from the following formula :



Üᾼᾏ

Ì

Ĩ

ÜĂ ᾚN Üſſᾏ Ń

Ì ∙ Ăᾏ


Ăᾚ : Modulus of bending elasticity of inner layer or outer layer specified in Ch 1, 304.

(NÕmmĪ)


Ăᾏ :

Modulus of compressive elasticity of core obtained from the test specified in Ch 3,

image

Sec 28 of Guidance Approval, Etc. or the

for Approval of Manufacturing Process and Type

result for related test among Ch 3, 206. of this rules.

image


(NÕmmĪ)

ſſᾏ : Compressive strength of core obtained from the test specified in Ch 3, Sec 28 of Guidance for Approval of Manufacturing Process and Type Approval, Etc. or the result for related test among Ch 3, 206. of this rules. (NÕmmĪ)

ᾼᾏ : Thickness of core (mm ).