1. What is Section Modulus?

The section modulus (Z) is a geometric property for a cross section used in the design of beams or flexural members. For I-beams, it accounts for the shape's resistance to bending.

2. How Does the Calculator Work?

The calculator uses the I-beam section modulus formula:

Where:

• \( Z \) — Section modulus (m³)
• \( b \) — Flange width (m)
• \( h \) — Total height (m)
• \( b_i \) — Inner flange width (m)
• \( h_i \) — Inner height (m)

Explanation: The formula calculates the difference between the full rectangular section and the inner removed section, divided by half the height.

3. Importance of Section Modulus

Details: Section modulus is crucial for determining a beam's strength in bending. Higher values indicate greater resistance to bending moments.

4. Using the Calculator

Tips: Enter all dimensions in meters. Ensure inner dimensions are less than outer dimensions for valid results.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between elastic and plastic section modulus?
A: Elastic modulus (Z) assumes material remains elastic, while plastic modulus accounts for full section yielding.

Q2: How does section modulus relate to moment capacity?
A: Moment capacity = Z × allowable stress. Higher Z means greater bending moment capacity.

Q3: What if my I-beam has unequal flanges?
A: This calculator assumes symmetrical I-beams. For unsymmetrical sections, more complex calculations are needed.

Q4: Are there standard I-beam section modulus values?
A: Yes, steel manuals provide Z values for standard I-beam sizes (e.g., W-shapes, S-shapes).

Q5: How does web thickness affect section modulus?
A: Thicker webs increase section modulus, but flange dimensions typically dominate the calculation.