## Helical Spring Design Guide.xls

Description:

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
http://www.roymech.co.uk/Useful_Tables/Springs/Springs_helical.html
http://www.thecartech.com/subjects/machine_elements_design/helical_springs.htm

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
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

Calculation Reference
Machine Design

Elements of Mechanical Design

Design of Springs

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Submitted On:
25 Nov 2011
Submitted By:
File Date:
11 Feb 2011
File Version:
1.0
File Size:
569.00 Kb
File Type:
xls
XLC:
126
Rating:
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#1 trophy 2013-01-19 18:27
ty 4 help