Rist, M.A. and Reed, R.C.
|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1179/026708301225000554|
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A new methodology has been devised for the optimisation of material parameters in equations that govern the tertiary creep deformation of single crystal superalloys. Such information is ordinarily extracted by conducting a series of mechanical experiments over a range of appropriate environmental conditions, e.g. at various fixed stresses and temperatures. However, the current technique allows material behaviour to be characterised from a limited number of tests of short duration performed under non-uniform stress. A strategy is presented in which the time dependent strain response under a distributed stress gradient is measured using a novel testpiece geometry incorporating a concave gauge length profile. Spatial strain distribution is determined by accurate post-deformation measurement of specimen shape. Both spatial and temporal deformation are then simulated using a well founded mechanistic damage model, and the agreement between model results and experimental data is optimised by systematic perturbation of model parameters using the Nelder-Mead direct search method, i.e. an inverse modelling approach is applied. The overall strategy has been successfully, validated for SRR99 by direct comparison with a database of more conventional tensile creep data, but it has the potential for broad application in cost effective and efficient prototyping of new materials generally.
|Item Type:||Journal Article|
|Academic Unit/Department:||Mathematics, Computing and Technology > Engineering & Innovation
Mathematics, Computing and Technology
|Depositing User:||Martin Rist|
|Date Deposited:||22 Feb 2007|
|Last Modified:||14 Jan 2016 16:28|
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