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dc.contributor.authorLiu, Junnb_NO
dc.date.accessioned2014-12-19T11:17:52Z
dc.date.available2014-12-19T11:17:52Z
dc.date.created2004-10-22nb_NO
dc.date.issued2004nb_NO
dc.identifier125286nb_NO
dc.identifier.isbn82-471-6458-2nb_NO
dc.identifier.urihttp://hdl.handle.net/11250/228944
dc.description.abstractThis work develops a new void growth model which is capable of describing the deformation and fracture of ductile materials under dynamic loading conditions. A representative volume element (RVE) which consists of a spheroidal void and a confocal spheroidal cell has been studied. A power law visco-plastic matrix material was assumed in the study in order to include the strain rate sensitivity effect. The formulations of Gåråjeu's model were used as basis for mathematical derivation. Particular attention is paid to inertia effect. In the new constitutive equations the inertia effect is represented by an individual term in the mesoscopic stress expression compared with the Gåråjeu's model. And this term is a function of the current void shape, void size, mesoscopic strain rate and matrix material density. A parametric study of the new model has been carried out by calculating the constitutive equations using FORTRAN code. Inertia effect and strain rate sensitivity have been evaluated numerically. The results of the new model have been shown to agree with the existing models very well. The relationships between inertia and parameters such as void shape, void size, strain rate, matrix material properties and void volume fraction were explained in details. It has been found that the strain rate effect dominates the void growth process at the early stage, and the effect decreases as the time elapses. FEM model analysis has been carried out to evaluate the new void growth model by ABAQUS. A special velocity boundary condition has been used in the FEM simulations to get the identical strain rate boundary condition as in the analytical calculations. It has been shown that the agreement of the present model with the FEM models is quite satisfactory on a wide range of strain rate, except the void shape which can not be predicted accurately. It has been found that the inertia effect is very small under the strain rate from quasi static up to several thousand 1/s.nb_NO
dc.languageengnb_NO
dc.publisherFakultet for ingeniørvitenskap og teknologinb_NO
dc.relation.ispartofseriesDoktoravhandlinger ved NTNU, 1503-8181; 2004:118nb_NO
dc.subjectMaterials scienceen_GB
dc.subjectTECHNOLOGY: Materials scienceen_GB
dc.titleA new dynamic void Growth Modelnb_NO
dc.typeDoctoral thesisnb_NO
dc.source.pagenumber114nb_NO
dc.contributor.departmentNorges teknisk-naturvitenskapelige universitet, Fakultet for ingeniørvitenskap og teknologinb_NO
dc.description.degreePhD i produktutvikling og materialernb_NO
dc.description.degreePhD in Engineering Design and Materialsen_GB


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