Aluminium bulb plates for marine application

IS 6476: Scope & Key Sectional Properties

Scope (Clause 5.3):

• Provides sectional properties for aluminium bulb flats for structural use.
• Tables 1 & 2 list properties for sections without and with plates (5, 10, 15 mm thickness).

Key Letter Symbols (Clause 3.1)

Important Dimensions & Properties (Excerpt from Table 1)

Mass based on aluminium density = 2.65 g/cm³.

IS 6476: Definitions & Key Symbols (Clause 2.0 & 3.1)

This standard defines symbols and sectional properties for aluminium alloy bulb sections used in structures.

Key Letter Symbols:

Sectional Properties Table (Excerpt for AMBW Series):

Mass based on aluminium density = 2.65 gm/cm³.

Notes:

• Section modulus (Zx) helps in bending design.
• Moment of inertia (Ix) is crucial for stiffness and deflection calculations.
• Plate thickness and width relate to additional reinforcement.

flowchart LR
    A[Sectional Area (a)] --> B[Mass per unit length (M)]
    B --> C[Centre of Gravity (O)]
    C -->

IS 6476: Key Formulas, Tables & Specifications for Materials

1. Sectional Properties (Clauses 5.3 & 3.1)

• Symbols:
  • ( a ) = Sectional area (without plate) [cm²]
  • ( M ) = Mass per unit length (without plate) [kg/m]
  • ( e_x ) = Distance of centroid from outer face of bulb [cm]
  • ( I_x ) = Moment of inertia about centroidal axis [cm⁴]
  • ( Z_x ) = Section modulus [cm³]
  • ( t ) = Plate thickness (5, 10, 15 mm)
  • ( L = 40 \times t ) (width of plate)

2. Material Dimensions & Limits (Clause 2.0)

• Maximum radius ( R = 0.8 ) mm
• Maximum thickness ( T_e = 2.0 ) mm
• Maximum corner radius ( r_c = 2.0 ) mm

3. Sample Sectional Properties from Tables 1 & 2 (without plate)

(Refer to IS 6476 Tables 1 & 2 for full details and plate options)

4. Mass Calculation

• Based on density ( \rho = 2.65

IS 6476: Dimensions and Mass for Indian Standard Bulb Plates

Key Specifications:

• Maximum corner radius, R = 0.8 mm
• Maximum edge thickness, Te = 2.0 mm
• Radius of curvature, rc = 2.0 mm max
• Density used for mass calculations = 2.65 g/cm³

Dimensions & Mass (Typical from Tables):

(Refer to IS 6476 Table 1 & 2 for full range)

Sectional Properties (Example for AMBW 100):

IS 6476: Sectional Properties Key Points

Symbols (Clause 3.1)

• a = Sectional area (without plate), cm²
• M = Mass per unit length (without plate), kg/m
• ex = Distance of centroid from outer face of bulb, cm
• Ix = Moment of inertia about centroidal axis, cm⁴
• Zx = Section modulus, cm³
• t = Plate thickness (5, 10, or 15 mm)
• L = Width of plate = 40 × t

Sectional Dimensions & Properties (Tables 1 & 2)

• Sections designated AMBW and AMB with dimensions H, C, S1, S2, r1, r2, etc.
• Radius of curvature r max = 0.8 to 2.0 mm depending on section.
• Mass based on density 2.65 g/cm³.
• Properties tabulated for sections without and with plates of thickness 5, 10, 15 mm.

Example Table Extract (Section AMBW 100 without plate)

Important Notes

• Section modulus Zx and moment of inertia Ix increase with plate thickness.
• Centroid location ex shifts with addition of plate.
• Use these tables directly for design calculations involving bending, shear, and axial loading.

flowchart LR
    A[Section Dimensions] --> B[Calculate Area (a)]
    B --> C[Find Centroid (ex)]
    C --> D[Compute Ix (Moment of Inertia)]
    D --> E[Calculate Zx (Section Modulus)]
    E --> F[Determine Mass per unit length (M)]
    F --> G[Use for Structural Design]

Use the tables in IS

IS 6476 - Manufacturing Requirements: Key Formulas, Tables & Specs

1. Sectional Properties (Clause 5.3 & Tables 1, 2)

• Tables provide detailed dimensions, mass, and sectional properties for aluminum bulb flats (AMB/AMBW).
• Key parameters include:

2. Manufacturing Tolerances (Clause 2.0)

• Maximum radius of curvature (r) at bends:
  • R = 0.8 mm max (for some sections)
  • rc = 2.0 mm max (for others)
• Thickness tolerance: Te = 2.0 mm max

3. Typical Dimensions & Properties Example (from Table 1 for AMBW 100)

4. Formulas

• Section modulus:
  [ Z_x = \frac{I_x}{e_x} ]

• Plate width:
  [ L = 40 \times t ]

5. Summary

• Use Tables 1 & 2 for detailed sectional properties.
• Maintain bend radius and thickness tolerances as per Clause 2.0.
• Plate thicknesses standardized at 5, 10, 15 mm with width

IS 6476: Testing and Compliance Key Points

Sectional Properties (Clauses 3.1 & 5.3)

• Symbols & Definitions:

• Tables 1 & 2 provide sectional properties for quick reference.

Rounding Off (Clause 0.7)

• Results of tests or calculations must be rounded off as per IS 2:1960.
• Retain the same number of significant digits as specified values in IS 6476.

Compliance Summary

• Use sectional properties from Tables 1 & 2 for design checks.
• Ensure test/calculation results are rounded per IS 2:1960.
• Confirm plate thickness and dimensions comply with specified multiples.

flowchart LR
    A[Start: Test/Analysis] --> B[Calculate/Observe Value]
    B --> C{Round off per IS 2:1960}
    C --> D[Compare with Specified Values]
    D --> E{Complies?}
    E -->|Yes| F[Accept Section]
    E -->|No| G[Review Design/Material]

This ensures standardized evaluation and uniform compliance with IS 6476.

IS 6476: Marking and Identification of Aluminium Bulb Plate Sections

Key Specifications (Clause 7.1 & 7.2)

• Marking on each lot/bundle must include:

  • Designation (section type)
  • Alloy and temper
  • Manufacturer’s name
  • Lot number/year of manufacture

• Standard Mark:

  • Bulb plate sections may carry the BIS Standard Mark as per Clause 7.2.
  • This mark certifies compliance with BIS inspection, testing, and quality control.

Letter Symbols (Clause 3.1)

Section Properties Reference (Clause 5.3)

• Refer Tables 1 & 2 for sectional properties (area, moment of inertia, modulus, etc.) for design and verification.

Summary Table of Marking Requirements

flowchart TD
    A[Lot/Bundle of Bulb Plate Sections] --> B[Marking]
    B --> C[Designation]
    B --> D[Alloy & Temper]
    B --> E[Manufacturer's Name]
    B --> F[Lot Number/Year]
    B --> G[Standard Mark (optional)]

Use this marking to ensure traceability, quality assurance, and compliance with IS 6476.

IS 6476 Key References: Sectional Properties & Symbols

1. Letter Symbols (Clause 3.1)

• a = Sectional area (without plate)
• M = Mass per unit length (without plate)
• 0 = Centre of gravity
• ex = Distance of centre of gravity from outer face of bulb
• Ix = Moment of inertia about centroidal axis
• Zx = Section modulus
• t = Plate thickness (5, 10, 15 mm)
• L = Width of plate = 40 × t

2. Sectional Properties Tables (Clause 5.3)

• Tables 1 & 2 provide detailed sectional properties for aluminium bulb sections with and without plates.
• Properties include:
  • Dimensions (H, C, S1, S2, r1, r2) in mm
  • Mass (kg/m)
  • Area (cm²)
  • Centroid location (ex in cm)
  • Moment of inertia (Ix in cm⁴)
  • Section modulus (Zx in cm³)

3. Example Table Extract (for AMBW 50 section without plate):

4. Notes:

• Mass is based on aluminium density = 2.65 g/cm³
• Plate thickness affects sectional properties; data is given for 5, 10, 15 mm plates.
• Radii limits: r_c = 2.0 mm max, R = 0.8 mm max, Te = 2.0 mm max.

flowchart LR
  A[Sectional Dimensions] --> B[Calculate Area (a)]
  B --> C[Determine Mass per unit length (M)]
  C --> D[Find Centre of

IS 6476 Annexes: Key Formulas, Tables & Specifications

Symbols (Clause 3.1)

• a = Sectional area (cm², without plate)
• M = Mass per unit length (kg/m, without plate)
• ex = Distance of centroid from outer face of bulb (cm)
• Ix = Moment of inertia (cm⁴)
• Zx = Section modulus (cm³)
• t = Plate thickness (5, 10, 15 mm)
• L = Plate width = 40 × t (mm)

Section Dimensions & Properties (Tables 1 & 2)

• Sections AMB and AMBW are tabulated with:
  • Height (H), Width (C), radii (S1, S2, r1, r2), plate thickness (t)
  • Mass (M), Area (a), centroid location (ex)
  • Moment of inertia (Ix), Section modulus (Zx)
• Properties are given without plate and with plates of thickness 5, 10, 15 mm.

Example Table Extract (AMB 50 Section without plate)

Plate Dimensions

• Plate width L = 40 × t (e.g., for t=5 mm, L=200 mm)
• Mass and sectional properties increase with plate thickness.

Notes:

• Radius limits: rc ≤ 2.0 mm, R ≤ 0.8 mm, Te ≤ 2.0 mm.
• Mass based on density 2.65 g/cm³.
• Use sectional properties for design calculations such as bending, shear, and axial load capacity.

flowchart LR
    A[Section Dimensions] --> B[Calculate Area (a)]
    B --> C[Find Centroid (ex)]
    C --> D[Calculate Ix, Zx]
    D --> E[Add Plate Properties (if any)]
    E -->