1. What is the Compression Spring Formula?

The compression spring formula calculates the spring rate (k) based on the material properties and geometric dimensions of the spring. It's essential for designing springs with specific stiffness characteristics.

2. How Does the Calculator Work?

The calculator uses the compression spring formula:

Where:

• \( k \) — Spring rate (N/m)
• \( G \) — Shear modulus of the material (Pa)
• \( d \) — Wire diameter (m)
• \( D \) — Mean coil diameter (m)
• \( N \) — Number of active turns

Explanation: The formula shows that spring rate is directly proportional to the shear modulus and the fourth power of wire diameter, and inversely proportional to the cube of mean diameter and number of active turns.

3. Importance of Spring Rate Calculation

Details: Accurate spring rate calculation is crucial for mechanical design, ensuring proper force-deflection characteristics in applications like automotive suspensions, industrial machinery, and consumer products.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure wire diameter and coil diameter are in meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical shear modulus for spring steel?
A: For common spring steels, G is typically around 79.3 GPa (79.3 × 10⁹ Pa).

Q2: How does wire diameter affect spring rate?
A: Spring rate increases with the fourth power of wire diameter, making it the most influential parameter.

Q3: What are active turns?
A: Active turns are the coils that contribute to spring deflection. Ground ends typically count as 1/2 turn each.

Q4: Can this formula be used for extension springs?
A: The basic formula applies, but extension springs have additional considerations like initial tension.

Q5: What's the difference between spring rate and spring constant?
A: They are the same - both refer to the force required to deflect the spring by a unit distance (N/m).