3D Scanners

A white paper to assist in the evaluation of 3D scanning hardware solutions.

Salary Expectation

8 things to know about the interview question "What's your salary expectation"?

Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

Desktop Engineering

Design, simulation, test, prototyping and high performance computing.

more free magazines
Fatigue is an issue in springs subjected to cyclic loading, where the force on the spring varies between a maximum and minimum value. For example, the springs in a car's shock absorption system would be subject to fatigue loading. Over time, excessive cyclic stresses from fatigue can cause the spring to fail.

Use this calculator to predict if a known spring subjected to a known range of loading forces will be in danger of failing from fatigue. The calculator outputs a GO / NO-GO assessment after checking the maximum shear stresses in the spring against Soderberg's criterion.

Inputs
  Spring free length, Lfree:    
  Spring constant, k:    
  Maximum force on spring, Fmax:    
  Minimum force on spring, Fmin:    
  Wire diameter, d:    
  Outer diameter of spring, Douter:    
  Material's limiting fatigue stress:    
  Material's yield stress:    
  Factor of safety:    
Answers
  Minimum length of spring (under Fmax):  3.85  in
  Mean component of shear, tmean:  13.4  ksi
  Alternating component of shear, talt:  2.68  ksi
  Soderberg limit for talt:  3.91  ksi
 
Fatigue Check:  Your spring is safe from fatigue.
Equations Behind the Calculator
See the companion page to view the equations for this calculator.