Section 10 Limiting stress coefficients
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Clasifications Register Rules and Regulations - Rules for the Classification of Air Cushion Vehicles, July 2022 - Chapter 3 Hull Structures - Section 10 Limiting stress coefficients

Section 10 Limiting stress coefficients

Parent topic: Chapter 3 Hull Structures

10.1 Limiting stress coefficients for local loads

10.1.1 The nominal limiting stress requirements for plating and primary and secondary stiffening members subject to local loading conditions are given in terms of limiting stress coefficients, see Table 3.10.1 Limiting stress coefficients for local loading. The coefficients are given as a proportion of the 0,2 per cent proof stress of the material, except where stated otherwise.

10.1.2 The limiting stress coefficients for structural elements subject to global loading are given in Table 3.10.2 Limiting stress coefficients for global loading.

Table 3.10.1 Limiting stress coefficients for local loading

  Limiting stress coefficient
Item Bending
f σ 		Shear
f Ʈ 		Equivalent
f e
Bottom and side structure
Plating 0,67 — —
Stiffening 0,67 0,39 —
Machinery foundations 0,55 0,32 0,75
Deck structure
Plating 0,75 — —
Stiffening 0,65 0,38 —
Superstructure and deck-house
Plating and stiffening 0,75 0,43 —
Bulkheads
Watertight bulkhead plating 1,0 — —
Watertight bulkhead stiffening 0,95 0,55 1,0
Watertight bulkhead doors and hatches 0,825 0,48 0,825
Structure supporting watertight doors and hatches 0,80 0,46 —
Slinging and jacking
Supporting structure 0,50 0,29 —
Eyeplates 0,25 (see Note)
Hull appendages
Skirt attachments 0,50 (see Note)
Side bodies 0,67 0,39 —
Landing pads and skids 0,67 0,39 —
Special features
Vehicle decks and ramps 0,50 0,29 0,75
Supporting structure and tie-down fittings 0,67 0,39 0,86
Crane foundations 0,70 0,40 0,75
Anchoring and mooring equipment
Equipment attachments and fittings 0,90 0,52 —
Equipment supporting structure 1,0 0,58 —
Structures and attachments subjected to collision loads      
Equipment attachments (see Note) 0,90 0,52 —
Equipment supporting structure (see Note) 0,90 0,52 —

Note Limiting stress coefficient is given as a fraction of the Ultimate Tensile Strength (UTS) of the material.

Table 3.10.2 Limiting stress coefficients for global loading

Item Limiting stress coefficient
  Bending
f σg 		Shear
f Ʈg 		Equivalent
f eg
Global load case      
Wave impact 0,67 0,67 0,70
Floating 0,67 0,67 0,70
Slinging and jacking 0,50 0,50 0,53
Parking 0,50 0,50 0,53
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