Senior Scientific Officer, Military Engineering Experimental Establishment, Christchurch, Hampshire
Pages: 25 Published: Jan 1970
In constant amplitude tests, main girder-bridge panels drawn from Ordnance store had slightly longer lives than newly made panels. Preloading and the improvement of a weld detail doubled lives, but shot peening was not effective. Tests below the Charpy transition temperature showed no change in life. Some Ordnance panels had significantly reduced lives due to prior fatigue damage. Block program tests gave cumulative cycle ratios of approximately 2, increasing with decrease in maximum stress and severity of the program. There was evidence of stresses below the endurance limit being beneficial to fatigue life. The manufacturing method for transoms or cross girders was shown to have an important bearing on fatigue life. Modes of failure are discussed together with the application of fatigue gages to give prior warning of fatigue failure.
testing, metals, low-alloy constructional steel, welding, fatigue (of metals), block-program tests, single-jump tests, preloading, shot-peening, sub-transition temperature tests, service damage, stress raisers, fatigue gages, crack propagation, load spectra
Paper ID: STP32033S