Simulation of softening in high pressure torsion process using continuum damage mechanics model

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211033883 ◽

2021 ◽

pp. 095440622110338

Author(s):

Shubhi Katiyar ◽

Prakash Mahadeo Dixit

Keyword(s):

High Pressure ◽

Damage Mechanics ◽

High Pressure Torsion ◽

Compressive Load ◽

Continuum Damage Mechanics ◽

Material Model ◽

Work Piece ◽

Continuum Damage ◽

Mechanics Model ◽

Insight Into

Severe Plastic Deformations (SPD) processes are used for grain refinement without any loss in ductility. Among various SPD processes, High Pressure Torsion (HPT) is extensively used in industries due to generation of high angle grain boundaries and cost effectiveness. Very little work has been reported on the numerical analysis of softening with recovery that might occur in a work-piece undergoing HPT. The present work is an attempt to study the softening behaviour in HPT processed mild steel and aluminium alloy using the Lemaitre’s continuum damage mechanics (CDM) model. This model is implemented in ABAQUS/Explicit through a user defined material model subroutine (VUMAT). A parametric study is carried out to study the effect on softening of various parameters like the compressive load, the friction at the die-workpiece interface, and the height to diameter ratio. Information about the softening with recovery provides an insight into the hardness and microstructure homogeneity in HPT processed work-piece, which is useful in the design of HPT process.

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Modelling the asymmetric tension–compression properties of additively manufactured alloys using continuum damage mechanics

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/14644207211013434 ◽

2021 ◽

pp. 146442072110134

Author(s):

A Nayebi ◽

H Rokhgireh ◽

M Araghi ◽

M Mohammadi

Keyword(s):

Damage Mechanics ◽

Continuum Damage Mechanics ◽

Element Model ◽

Continuum Damage ◽

Compression Tests ◽

Compression Properties ◽

Mechanics Model ◽

Stress Components ◽

Tension And Compression ◽

Closure Effect

Additively manufactured parts often comprise internal porosities due to the manufacturing process, which needs to be considered in modelling their mechanical behaviour. It was experimentally shown that additively manufactured parts’ tensile and compressive mechanical properties are different for various metallic alloys. In this study, isotropic continuum damage mechanics is used to model additively manufactured alloys’ tension and compression behaviours. Compressive stress components can shrink discontinuities present in additively manufactured alloys. Therefore, the crack closure effect was employed to describe different behaviours during uniaxial tension and compression tests. A finite element model embedded in an ABAQUS’s UMAT format was developed to account for the isotropic continuum damage mechanics model. The numerical results of tension and compression tests were compared with experimental observations for additively manufactured maraging steel, AlSi10Mg and Ti-6Al-4V. Stress–strain curves in tension and compression of these alloys were obtained using the continuum damage mechanics model and compared well with the experimental results.

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Predicting the wear coefficient and friction coefficient in dry point contact using continuum damage mechanics

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650118785045 ◽

2018 ◽

Vol 233 (3) ◽

pp. 447-455 ◽

Cited By ~ 1

Author(s):

Sahar Ghatrehsamani ◽

Saleh Akbarzadeh

Keyword(s):

Friction Coefficient ◽

Damage Mechanics ◽

Point Contact ◽

Continuum Damage Mechanics ◽

Continuum Damage ◽

Wear Coefficient ◽

Mechanics Model ◽

Pin On Disk ◽

Disk Test ◽

The Continuum

Wear coefficient and friction coefficient are two of the key parameters in the performance of any tribo-system. The main purpose of the present research is to use continuum damage mechanics to predict wear coefficient. Thus, a contact model is utilized that can be used to obtain the friction coefficient between the contacting surfaces. By applying this model to the continuum damage mechanics model, the wear coefficient between dry surfaces is predicted. One of the advantages of using this model is that the wear coefficient can be numerically predicted unlike other methods which highly rely on experimental data. In order to verify the results predicted by this model, tests were performed using pin-on-disk test rig for several ST37 samples. The results indicated that the wear coefficient increases with increasing the friction coefficient.

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