Helical Spring Design Guide.xls



Outline Calculation Procedure
1) Purpose of calculation
The design of a helical spring using mechanical design formula and material lookup tables.
Check dimensional limits, strength limits and buckling limits against the operational requirements.
2) Calculation Reference
3) Calculation Validation
Formulas checked using the XLC add-in
4) Calculation Units
5) Sketch
6) Main Input Parameters
Wire diameter
Spring mean diameter
Free length
Number of turns
% length on installation and operational max compression
7) Spring Ends
Number of inactive turns due to closed and ground ends
Effective number of turns
Length modifier
Inactive Length
Active Length
Pitch (unloaded).
Solid Length
8) Material Properties
Material Constant
Material index
Ultimate Tensile Stress
Torsional yield to tensile ultimate strength factor
Torsional yield stress
Conversion Factor from Mpa to selected system of units
Torsional yield stress converted to select system of units
Young's Modulus
Modulus of rigidity assuming a Poisson's ratio of 0.3
9) Spring Deflection Characteristics
Spring Index
Spring Rate
Force to close the spring
10) Spring Strength Characteristics
Wahl factor
Torsional Stress Rate
Force to yield spring
Spring extension to yield spring
11) Spring Buckling
Buckling critical compression length
Buckling force
12) Operational Limits
Installed Length
Installed force
Operating Length
Maximum working load

Calculation Reference
Machine Design
Elements of Mechanical Design
Design of Springs

Calculation Preview

11 Feb 2011
Last Modified
25 Nov 2011
File Size:
569.00 Kb
File Version:

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