Section 6 Single Skin Construction

601. Consideration of buckling

Buckling strength of single skin panels subjected to longitudinal hull girder strength or local com- pressional loads will be dealt with individually.

602. Minimum requirements to structural single skin plates

1. The reinforcement of single skin laminates is to contain at least 40 % continuous fibres.

2. The mass of reinforcement (g/m2) in single skin panel should normally not be less than following: However, details including laminating process such as work sheets to be submitted.

≥

for m

:

:

mass of reinforcement per unit area, g m

given in Table 3.5.5. (For mixed material reinforcements can be found by linear

terpolation in the table according to weight per unit area.)

given in Table 3.5.5.

: length between perpendiculars.

to the relative percentage of each material with respect

Table 3.5.5 and

603. Laterally loaded single skin laminates

1. Assumptions

(1) The formulas given below are valid under the following assumptions.

(A) The principal directions of reinforcement are parallel to the edges of the panel.

(B) The difference in the modulus of elasticity in the two principal direction of reinforcement is not more than 20 %.

(C) The load is uniformly distributed.

(2) For laminates not complying with the above (1) are to be in accordance with the discretion of the Society.

2. Laminates exposed to combined bending and membrane stresses.

(1) For a given design pressure the thickness requirements are related to a laminate deflection factor

(=/t) and an allowable combined stresses (bending stress + membrane stress).

(2) The required thickness to meet a specific value of d in association with a given design pressure

is given by the following formula :

mm

and : refer to Table 3.5.9.

(3) The combined stresses (bending stress + membrane stress) corresponding to the thickness found in (2) is given the following formula :

N mm

and

: refer to Fig 3.5.9.

: refer to Fig

Fig 3.5.9 Factors

and

Fig 3.5.10 Factors and

3. Allowable stresses and deflections

The maximum combined stresses (bending stress + membrane stress) and deflections are not to be greater than given values in the Table 3.5.6.

Table 3.5.6 Allowable Stresses and Deflection

604. Stiffeners

1. Section modulus

(1) The section modulus of longitudinals, beams, frames and other stiffeners subject to lateral pres- sure is not to be less than that obtained from the following formula :

c

bending moment factor, defined in Sec 7, Table 3.5.10 for load and boundary con- ditions, and Table 3.5.8 for structural members.

spacing of stiffeners (m ).

: span of the stiffeners (m ).

: allowable stress, defined in Table 3.5.7.

(2) When calculating the section modulus of top hat stiffeners the effect of possible variations in

the modulus of elasticity through the section should be taken be determined in accordance with 704. Par 2.

into account. Effective flange is to

Table 3.5.7 Allowable Stresses Table 3.5.8 Bending Moment Factor ( )