A continuum damage mechanics model for ductile fracture

Ductile fracture occurs due to microvoid nucleation, growth and, finally, coalescence into microcracks. These microcracks grow in the presence of stresses leading to fracture. In this work, a criterion based on this phenomenon is used to simulate ductile fracture in a class of steel specimens. A critical value of the damage variable, estimated from experimental results, is used as an indicator of fracture initiation. A continuum damage mechanics model is employed to incorporate the damage in the constitutive relation of the material. A damage growth law based on experimental results is used. It is observed that the damage reaches the critical value first at the center in both the cylindrical and prenotched specimens. Thus, the failure begins at the center and then grows radially outward toward the free surface. The analysis is carried out till the damage reaches the critical value across the whole cross-section, at which point the specimen is considered to have failed.

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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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