Papers by Author: David Taylor

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Authors: R.J. McConnell, C. Moriarty, David Taylor
Authors: David Taylor, Jan Hazenberg, Fergal O'Brien, T. Clive Lee
Abstract: We conducted work to investigate fatigue cracking and repair in bone, in which we discovered the mechanism by which bone is able to detect the presence of microscopic cracks and thus initiate repair processes. This investigation has made use of theoretical and applied fracture mechanics, in combination with cell biology. It is the first example of a completely-understood mechanism showing how living cells can respond to mechanical stimuli.
Authors: David Taylor
Abstract: The work described below investigates, for the first time, the link between microstructural parameters such as grain size and the length constant L which is known as the critical distance. L is frequently used in the prediction of failure processes such as brittle fracture and fatigue, initiated at stress concentration features such as notches. Values of L were calculated using data from the literature on the effect of short cracks and notches in steels and ceramics. In some cases, simple relationships could be established between L and the grain size, or other microstructural features. Sometimes L was found to be much larger than anything in the microstructure and appeared to be related to the size of the damage zone at failure.
Authors: Luca Susmel, David Taylor
Abstract: The present paper is concerned with the use of the Theory of Critical Distances (TCD), applied in the form of the Point Method (PM), to estimate the range of the threshold value of the stress intensity factor, Kth, as well as the plane strain fracture toughness, KIc. In more detail, by reanalysing a large amount of experimental data taken from the literature, it is proved that Kth can successfully be evaluated through the plain fatigue limit and another fatigue limit generated by testing samples containing a known geometrical feature, whereas KIc is suggested here as being estimated by using experimental results generated by testing samples weakened by notches of different sharpness. The validation exercise summarised in the present paper fully confirms that the TCD is not only a reliable method suitable for performing the static and fatigue assessment of real components, but also an efficient experimental strategy capable of accurately estimating the classical Linear Elastic Fracture Mechanics (LEFM) material properties.
Authors: David Taylor
Abstract: A few years ago we showed that the Theory of Critical Distances (TCD) and the Crack Modelling Method (CMM) could be used to predict the behaviour of welded joints of various geometries, in both steel and aluminum alloys. However we found that there were certain kinds of joints for which our methods, and also other methods which are commonly used, consistently underpredicted the fatigue strengths. Some explanations are suggested for this problem. Finally, mention is made of some of failure investigations in which the author has been involved, to illustrate the complexities which arise in real-world situations.
Authors: Luca Susmel, David Taylor
Abstract: The present paper is concerned with the use of the Modified Wöhler Curve Method (MWCM), applied in terms of nominal stresses, to estimate lifetime of notched components subjected to variable amplitude multiaxial fatigue loading. The MWCM is applied by defining the critical plane through that direction experiencing the maximum variance of the resolved shear stress: since the shear stress resolved along the above direction is a monodimensional quantity, fatigue cycles are directly counted by the classical Rain-Flow method. The performed validation exercise, based on an extensive experimental investigation, seems to strongly support the idea that the MWCM applied along with the classical nominal stress based approach is capable of accurately estimating fatigue damage also in notched components subjected to variable amplitude multiaxial load histories.
Authors: David Taylor, B. McCormack
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