Calculate Deflection Of Plywood

Deflection Formula:

\[ \delta = \frac{5 w L^4}{384 E I} \]

Uniform Load (w):

N/m

Length (L):

Modulus of Elasticity (E):

Moment of Inertia (I):

mm⁴

Deflection (δ):

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1. What is Plywood Deflection Calculation?

The plywood deflection calculation estimates the amount of bending or sagging that occurs when a plywood sheet is subjected to a uniform load. This is important for structural design and ensuring that plywood panels meet required performance standards.

2. How Does the Calculator Work?

The calculator uses the beam deflection formula:

\[ \delta = \frac{5 w L^4}{384 E I} \]

Where:

\( \delta \) — Deflection (mm)
\( w \) — Uniform load (N/m)
\( L \) — Length of the beam (mm)
\( E \) — Modulus of elasticity (Pa)
\( I \) — Moment of inertia (mm⁴)

Explanation: This formula calculates the maximum deflection of a simply supported beam with uniform load distribution. The deflection is proportional to the load and the fourth power of the length, and inversely proportional to the stiffness (EI) of the material.

3. Importance of Deflection Calculation

Details: Accurate deflection calculation is crucial for structural design, ensuring that plywood panels do not deflect excessively under load, which could lead to structural failure or serviceability issues.

4. Using the Calculator

Tips: Enter uniform load in N/m, length in mm, modulus of elasticity in Pa, and moment of inertia in mm⁴. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical modulus of elasticity for plywood?
A: The modulus of elasticity for plywood typically ranges from 6,000 to 10,000 MPa, depending on the grade and type of plywood.

Q2: How do I calculate moment of inertia for plywood?
A: For a rectangular cross-section, moment of inertia is calculated as I = (b × h³)/12, where b is the width and h is the thickness.

Q3: What is considered acceptable deflection for plywood?
A: Acceptable deflection typically follows the L/360 rule, meaning deflection should not exceed span length divided by 360.

Q4: Does this formula account for different support conditions?
A: This formula is for simply supported beams. Different support conditions (fixed, cantilever) require different deflection formulas.

Q5: How does moisture affect plywood deflection?
A: Moisture can reduce the modulus of elasticity and increase deflection. Always use appropriate values for the specific moisture conditions.