1. What is the Coil Spring Equation?

The coil spring equation calculates the spring constant (k) based on the material properties and geometry of the spring. It's fundamental in mechanical engineering for designing springs with specific stiffness characteristics.

2. How Does the Calculator Work?

The calculator uses the coil spring equation:

Where:

• \( k \) — Spring constant (N/m)
• \( G \) — Shear modulus of the material (Pa)
• \( d \) — Diameter of the spring wire (m)
• \( D \) — Mean diameter of the spring coil (m)
• \( N_a \) — Number of active turns

Explanation: The equation shows that spring stiffness increases with the fourth power of wire diameter, but decreases with the cube of coil diameter and linearly with the number of active turns.

3. Importance of Spring Constant

Details: The spring constant determines how much force is needed to compress or extend the spring by a given distance. It's crucial for designing suspension systems, mechanical watches, and many other applications.

4. Using the Calculator

Tips: Enter all values in the correct units. Typical shear modulus for steel is about 79.3 GPa (79.3 × 10⁹ Pa). Ensure all dimensions are accurate for precise results.

5. Frequently Asked Questions (FAQ)

Q1: What is shear modulus (G)?
A: Shear modulus is a material property that measures its stiffness in shear. It's also called the modulus of rigidity.

Q2: How does wire diameter affect spring constant?
A: Since k ∝ d⁴, doubling the wire diameter increases spring constant by 16 times.

Q3: What are active turns?
A: Active turns are the number of coils that are free to deflect under load, excluding any closed or ground ends.

Q4: Can this be used for non-circular wire springs?
A: No, this equation is specifically for round wire helical springs.

Q5: What's a typical spring constant range?
A: It varies widely from very soft springs (10 N/m) to very stiff ones (100,000 N/m) depending on application.