Modelling of compaction of metal powder and damage accum ulation due to fatigue in powder materials
(2004)- Abstract
- This thesis addresses powder manufactured (P/M) components, with special attention to the compaction process and to the sensitivity to damage accumulation due to fatigue within powder compacted specimens. Three dimensional simulations of the compaction process have been performed, using an explicit dynamic dilatant finite strain finite element code supplemented with the effects from contact friction within the die, modelled by Coulomb friction. The final porosity distribution as well as friction force characteristics obtained from simulations of compaction of specimens with circular and quadratic cross section were found to correlate with experimental findings. Two different porous material models where implemented using a viscoplastic... (More)
- This thesis addresses powder manufactured (P/M) components, with special attention to the compaction process and to the sensitivity to damage accumulation due to fatigue within powder compacted specimens. Three dimensional simulations of the compaction process have been performed, using an explicit dynamic dilatant finite strain finite element code supplemented with the effects from contact friction within the die, modelled by Coulomb friction. The final porosity distribution as well as friction force characteristics obtained from simulations of compaction of specimens with circular and quadratic cross section were found to correlate with experimental findings. Two different porous material models where implemented using a viscoplastic formulation, the Shima Oyane and the combined Fleck – Kuhn – McMeeking (FKM) and Gurson material models. Parameters in the constitutive models calibrated from experiments were found to be adjustable so as to capture the overall final porosity distributions. The possibility to determine the final porosity distribution within complex geometries at different compaction speeds was demonstrated for gear wheels using the combined FKM and Gurson model. The damage accumulation due to fatigue loading has been modelled in two dimensions using the Gurson material model, supplemented to account for isotropic as well as kinematic hardening, rate effects and adiabatic heat accumulation. Gear root damage at the center plane and at the surface of a gear wheel have been studied, with initial porosity distributions transferred from three dimensional simulations. The damage accumulation process was found to be highly localized, which points to the importance of correctly determining the porosity at critical regions of a component, thus diminishing the importance of an accurate overall porosity distribution description. A life estimate model, relating the number of cycles to failure to the applied fatigue load and initial porosity was also presented. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/466981
- author
- Cedergren, Joakim LU
- supervisor
- opponent
-
- Professor Ståhle von Schwerin, Per, Malmö
- organization
- publishing date
- 2004
- type
- Thesis
- publication status
- published
- subject
- keywords
- hydraulik, vakuumteknik, vibrationer, akustik, Maskinteknik, hydraulics, Mechanical engineering, friction, FEM, numerical modelling, continuum mechanics, fatigue loading, powder compaction, vacuum technology, vibration and acoustic engineering
- pages
- 88 pages
- publisher
- Division of Mechanics, Box 118, SE221 00 Lund,
- defense location
- Room M:B of the M-building at Lund Institute of Technology
- defense date
- 2004-05-26 10:15:00
- external identifiers
-
- other:ISRN:LUTFD2/TFME--04/2003--SE(1-88)
- ISBN
- 91-628-6076-3
- language
- English
- LU publication?
- yes
- additional info
- Article: Paper IThree-dimensional analysis of compaction of metal powder.J. Cedergren, N.J. Sørensen, A. BergmarkMechanics of Materials, 34, 43-59, 2002. Article: Paper IINumerical Investigation of powder compaction of gear wheels.J. Cedergren, N.J. Sørensen, S. MelinInternational Journal of Solids and Structures, 40, 4989-5000, 2003. Article: Paper IIINumerical investigation of P/M manufactured gear wheels subjected to fatigue loading.J. Cedergren, S. Melin, P. Lidström.Technical report, Division of Mechanics, Lund University, Sweden.Submitted for international publication. Article: Paper IVNumerical modelling of P/M steel bars subjected to fatigue loading using an extended Gurson model.J. Cedergren, S. Melin, P. Lidström.Technical report, Division of Mechanics, Lund University, Sweden.Submitted for international publication.
- id
- 502e0367-e77e-4c35-a05f-b9d6d5707234 (old id 466981)
- date added to LUP
- 2016-04-04 10:09:20
- date last changed
- 2018-11-21 20:57:05
@phdthesis{502e0367-e77e-4c35-a05f-b9d6d5707234,
abstract = {{This thesis addresses powder manufactured (P/M) components, with special attention to the compaction process and to the sensitivity to damage accumulation due to fatigue within powder compacted specimens. Three dimensional simulations of the compaction process have been performed, using an explicit dynamic dilatant finite strain finite element code supplemented with the effects from contact friction within the die, modelled by Coulomb friction. The final porosity distribution as well as friction force characteristics obtained from simulations of compaction of specimens with circular and quadratic cross section were found to correlate with experimental findings. Two different porous material models where implemented using a viscoplastic formulation, the Shima Oyane and the combined Fleck – Kuhn – McMeeking (FKM) and Gurson material models. Parameters in the constitutive models calibrated from experiments were found to be adjustable so as to capture the overall final porosity distributions. The possibility to determine the final porosity distribution within complex geometries at different compaction speeds was demonstrated for gear wheels using the combined FKM and Gurson model. The damage accumulation due to fatigue loading has been modelled in two dimensions using the Gurson material model, supplemented to account for isotropic as well as kinematic hardening, rate effects and adiabatic heat accumulation. Gear root damage at the center plane and at the surface of a gear wheel have been studied, with initial porosity distributions transferred from three dimensional simulations. The damage accumulation process was found to be highly localized, which points to the importance of correctly determining the porosity at critical regions of a component, thus diminishing the importance of an accurate overall porosity distribution description. A life estimate model, relating the number of cycles to failure to the applied fatigue load and initial porosity was also presented.}},
author = {{Cedergren, Joakim}},
isbn = {{91-628-6076-3}},
keywords = {{hydraulik; vakuumteknik; vibrationer; akustik; Maskinteknik; hydraulics; Mechanical engineering; friction; FEM; numerical modelling; continuum mechanics; fatigue loading; powder compaction; vacuum technology; vibration and acoustic engineering}},
language = {{eng}},
publisher = {{Division of Mechanics, Box 118, SE221 00 Lund,}},
school = {{Lund University}},
title = {{Modelling of compaction of metal powder and damage accum ulation due to fatigue in powder materials}},
year = {{2004}},
}