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Title: Analysis and use of resonance in the fatigue testing of helical springs
Author: Ward, A. P. B.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1988
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This work concerns the use of resonance, in a proposed test designed to rapidly determine the fatigue life of coil-springs. A method is described whereby any number of the lower natural frequencies and corresponsing mode-shapes, of a coil-spring, constrained by a variety of simple boundary-conditions, may be determined. A method which uses the predicted natural mode-shapes is described, whereby an index of stress, corresponding to the rate of fatigue damage to the coil-spring, resulting from: resonance, the application of opposing static longitudinal forces to the ends of the spring, and residual stresses, may be determined. The predicted stress is used, to determine the most useful of the classes of natural modes, for use in the proposed test of fatigue life, and a method whereby the fatigue life of a spring, resonating in this mode, may be determined. A jig has been designed to hold a spring of largely arbitrary geometry, in this mode of resonance, such that sufficient stress is induced in the wire, to exceed the endurance limit of the material of the spring's wire, for sufficient time to cause failure by fatigue. This includes a method for the application of opposing static longitudinal forces to the ends of the spring, should this be required to supplement the alternating stress caused by resonance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available