Mingjian Li, Ping Yang^*, Pengyang Zhao

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.2, pp. 2019-2034, 2024, DOI:10.32604/cmes.2024.048334 - 20 May 2024

Abstract The experimental results in previous studies have indicated that during the ductile fracture of pure metals, vacancies aggregate and form voids at grain boundaries. However, the physical mechanism underlying this phenomenon remains not fully understood. This study derives the equilibrium distribution of vacancies analytically by following thermodynamics and the micromechanics of crystal defects. This derivation suggests that vacancies cluster in regions under hydrostatic compression to minimize the elastic strain energy. Subsequently, a finite element model is developed for examining more general scenarios of interaction between vacancies and grain boundaries. This model is first verified and More >

Baisen Gao¹, Wei Huang^1,*, Shengnan Wang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.4, pp. 1-2, 2023, DOI:10.32604/icces.2023.010553

Abstract Additive manufacturing of metallic components can result in initial defects that significantly reduce their mechanical properties [1]. Therefore, there has been considerable interest in studying the fracture and damage behavior of such components through theoretical and experimental studies [2, 3]. Developing a reliable model for predicting the ductile fracture of additively manufactured components is currently of great importance. In this study, we conducted unit cell calculations with the calibration of experimental tests to investigate the ductile fracture of Ti-6Al-4V alloy fabricated through additive manufacturing. The stress triaxiality and Lode parameter were enforced constant for the… More >

M.N.D. Cherief¹, M. Elmeguenni¹, M. Benguediab¹

CMC-Computers, Materials & Continua, Vol.51, No.3, pp. 187-201, 2016, DOI:10.3970/cmc.2016.051.187

Abstract Impact behavior of polymers has received considerable attention in recent years, and much work based on fracture mechanic approaches has been carried out. In this paper, fracture behavior in large deformation of a high density polyethylene (HDPE) materials was investigated through experimental impact testing on single edge notched specimen (SENB) and by using theoretical and analytical fracture criteria concepts. Moreover, a review of the main fracture criteria is given in order to characterize the toughness of this polymer in the both cases (static and dynamic). The fractured specimens obtained from the Charpy impact test were More >

L. Li, S. Liu, H. Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.36, No.2, pp. 173-192, 2008, DOI:10.3970/cmes.2008.036.173

Abstract We study ductile fracture using Reproducing Kernel Particle Interpolation and the Gurson-Tvergaard-Needleman (GTN) model. The meshless simulations are compared with the available experimental results and previous finite element simulations for crack propagation. The results agree well with experimental results, and it is confirmed that the proposed method provides a convenient and yet accurate means for simulation of ductile fracture. More >

Sanjeev Saxena¹, N. Ramakrishnan¹, B.K. Dutta², P. Rama Rao³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.4, pp. 147-152, 2007, DOI:10.3970/icces.2007.001.147

Abstract Several methods are in vogue to understand the process of crack initiation and propagation in ductile materials. In an attempt to achieve a unified understanding of these methods, a large deformation finite element analysis has been carried out. An attempt has been made to understand ductile fracture by numerically determining the ductile fracture toughness by three different methods viz. 1) Load-displacement method 2) Path-integral method 3) Stretch zone width method (SZW). In addition, an attempt has to be made to explore the possibility of using `characteristic distance'(lc) approach for establishing fracture toughness. The present study… More >

M. Kikuchi¹, S. Sannoumaru²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.3, pp. 99-104, 2007, DOI:10.3970/icces.2007.001.099

Abstract Thickness effect is studied experimentally. At free surface of the specimen, shear lip fracture pattern appears, though dimple fracture pattern is observed inside of the specimen. The area of shear-lip fracture changes due to the change of the specimen thickness. In this study, experimental study is conducted by changing specimen thicknesses. Fracture surfaces are precisely observed using SEM, and dimple patterns on them are observed. At the free surface, very narrow no-void area is observed. By using FRASTA technique, dimple fracture process is simulated. It is found that shear-lip fracture appears after dimple fracture process. More >

M. Mashayekhi¹, S. Ziaei-Rad², J. Parvizian³, K. Nikbin¹, H. Hadavinia¹

Structural Durability & Health Monitoring, Vol.1, No.1, pp. 67-82, 2005, DOI:10.3970/sdhm.2005.001.067

Abstract The continuum mechanical simulation of microstructural damage process is important in the study of ductile fracture mechanics. An essential feature in these analyses, is the strong influence of stress triaxiality ratio, i.e. the ratio of mean stress to equivalent stress, on the rate of damage growth. In this paper, finite element simulation of damage evolution and fracture initiation in ductile solids will be investigated. A fully coupled constitutive elastic-plastic-damage model has been implemented. The stress update algorithm for the constitutive model is presented together with the consistent tangent operator, which is needed for implicit FEA. More >

N. Ramakrishnan¹, P. Rama Rao²

CMC-Computers, Materials & Continua, Vol.2, No.3, pp. 163-176, 2005, DOI:10.3970/cmc.2005.002.163

Abstract Ductile fracture is initiated by void nucleation at a characteristic distance (I_c) from the crack tip and propagated by void growth followed by coalescence with the tip. The earlier concepts expressed I_c in terms of grain size or inter-particle distance because grain and particle boundaries form potential sites for void nucleation. However, Srinivas et al. (1994) observed nucleation of such voids even inside the crack tip grains in a nominally particle free Armco iron. In an attempt to achieve a unified understanding of these observations, typical crack-tip blunting prior to ductile fracture in a standard C(T) specimen… More >