Enhanced fracture energy and effects of temperature at spalling in ceramics: continuum damage modelling

2000 ◽  
Vol 70 (1-3) ◽  
pp. 145-157 ◽  
Author(s):  
J. Najar ◽  
V. V. Silberschmidt ◽  
M. Müller-Bechtel
Keyword(s):  
Fracture Energy ◽  
Continuum Damage ◽  
Damage Modelling ◽  
Effects Of Temperature

Experimental and FEA Investigations on the Fracture Properties of Pipe Structures Under Internal Pressure in DBTT Region

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Zhao-Xi Wang ◽  
Fei Xue ◽  
Hui-Ji Shi ◽  
Jian Lu
Keyword(s):  
Energy Density ◽  
Fracture Energy ◽  
Transition Region ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Basic Material ◽  
Continuum Damage ◽  
Continuum Damage Model ◽  
Damage Models ◽  
Different Temperatures

The fracture behavior of pipes with penetrating cracks was experimentally investigated with the results of the load-deflection curves and crack length. J-R curves were obtained from the testing results for different temperatures. With the decrement in temperature, the critical J integral decreases and the tearing modulus increases. An updated continuum damage model was proposed, in which the fracture energy density as a function of the stress triaxiality, temperature and strain rate in the transition region was taken as the critical damage factor. The uni-axial tension experiments at different temperatures were carried out to obtain the basic material properties and the critical fracture energy density, to verify the validity of the damage model. Based on detailed finite element analyses with the proposed updated continuum damage model, the loading level of pipes with penetrating cracks was estimated and compared with the experimental results, meanwhile the fracture processes of the pipeline structure in the ductile-brittle-transition-temperature region were reproduced. It has been shown that the fracture process in the transition region strongly depends on both the stress and strain state, and can be effectively predicted using the continuum damage models incorporating with the stress state effect.

scholarly journals Continuum damage modelling and some computational issues

2002 ◽  
Vol 6 (6) ◽  
pp. 991-1017 ◽  
Author(s):  
Gilles Pijaudier-Cabot ◽  
Ludovic Jason
Keyword(s):  
Continuum Damage ◽  
Damage Modelling

scholarly journals Continuum damage modelling in geomechanics

2004 ◽  
pp. 77-105
Author(s):  
Gilles Pijaudier-Cabot ◽  
Ludovic Jason ◽  
Antonio Huerta ◽  
Jean-François Dubé
Keyword(s):  
Continuum Damage ◽  
Damage Modelling

Adhesion and Progressive Debonding of Polymer/Metal Interfaces: Effects of Temperature and Environment

1999 ◽  
Vol 563 ◽  
Author(s):  
Seung-Yeop Kook ◽  
Amol Kirtikar ◽  
Reinhold H. Dauskardt
Keyword(s):  
Fracture Energy ◽  
Interfacial Fracture ◽  
Fatigue Loading ◽  
Cyclic Fatigue ◽  
Rate Theory ◽  
Metal Interface ◽  
Polymer Metal ◽  
Interfacial Fracture Energy ◽  
Effects Of Temperature ◽  
Novolac Epoxy

AbstractThe interfacial fracture properties of a representative polymer/metal interface commonly found in microelectronic applications are examined. The double cantilever beam (DCB) configuration was used to investigate the effects of environmental variables on interfacial adhesion and progressive delamination under monotonic and cyclic fatigue loading conditions. The steady-state interfacial fracture energy, Gss, taken from the plateau of the R-curve, of a representative silica-filled Phenol-Novolac epoxy on a Nielectroplated Cu substrate showed little sensitivity to the presence of moisture. On the other hand, both the initiation interfacial fracture energy, Gi, and the entire progressive debond curve under fatigue loading were remarkably sensitive to moisture and temperature, respectively. Debonding is modeled in terms of interface structure, chemistry using chemical reaction rate theory, and relaxation process at the debond tip. The activation energy for stage I debond growth is found to be 140 kJ/mol and 63 kJ/mol for stage II for the current polymer/metal interface.

Effects of characteristic element length on fracture energy dissipation in continuum damage mechanics models

2021 ◽  
pp. 002199832110237
Author(s):  
Frank A Leone ◽  
Brian P Justusson
Keyword(s):  
Energy Dissipation ◽  
Aspect Ratio ◽  
Fracture Energy ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Band Width ◽  
Continuum Damage ◽  
Band Theory ◽  
Characteristic Element ◽  
Crack Band

Progressive damage finite element (FE) analysis methods based on continuum damage mechanics (CDM) use mesh regularization algorithms to ensure that fracture energy dissipation predictions are independent of problem discretization. Mesh regularization algorithms require some geometric input related to the discretization. When using crack band theory for mesh regularization, a characteristic element length is used to approximate the width of the region affected by the continuum crack, i.e., the crack band width. Inaccuracy in representing the crack band width significantly affects predictions in terms of fracture energy dissipation. For square elements misaligned by 45°, using a typical line length across an element rather than the crack band width overestimates dissipated fracture energy by 41%. Not accounting for element aspect ratio underestimates dissipated fracture energy by 29% and 50% for ratios of two and four, respectively. Herein, methods for calculating characteristic element lengths in fiber-reinforced materials are presented that account for meshes being misaligned with respect to material directions, element aspect ratio, and element skew. The limits of applicability of different crack band width approximations are explored through numerical crack growth studies and center notch tension FE analyses for different discretizations. Results are compared in terms of fracture energy dissipation to linear elastic fracture mechanics. Analyses with the proposed characteristic element lengths predict consistent fracture energy dissipation with various meshes. The proposed methods and the included studies on potential error in fracture energy dissipation provide analysts the basis to better understand error in CDM model predictions associated with simplified FE model preprocessing.

Computation of brittle fracture propagation in strain gradient materials by the FEniCS library

2020 ◽  
pp. 108128652095451 ◽  
Author(s):  
E Barchiesi ◽  
H Yang ◽  
CA Tran ◽  
L Placidi ◽  
WH Müller
Keyword(s):  
Brittle Fracture ◽  
Strain Gradient ◽  
Deformation Energy ◽  
Maximum Energy ◽  
Dissipated Energy ◽  
Gradient Term ◽  
Continuum Damage ◽  
Damage Modelling ◽  
Maximum Energy Release ◽  
Non Locality

Strain gradient continuum damage modelling has been applied to quasistatic brittle fracture within an approach based on a maximum energy-release rate principle. The model was implemented numerically, making use of the FEniCS open-source library. The considered model introduces non-locality by taking into account the strain gradient in the deformation energy. This allows for stable computations of crack propagation in differently notched samples. The model can take wedges into account, so that fracture onset can occur at wedges. Owing to the absence of a damage gradient term in the dissipated energy, the normal part of the damage gradient is not constrained on boundaries. Thus, non-orthogonal and non-parallel intersections between cracks and boundaries can be observed.

MOLECULAR DYNAMICS ANALYSIS FOR FRACTURE BEHAVIOR OF GRAPHENE SHEETS WITH V-SHAPED NOTCHES UNDER TENSION

NANO ◽  
2014 ◽  
Vol 09 (08) ◽  
pp. 1450087 ◽  
Author(s):  
TE-HUA FANG ◽  
WIN-JIN CHANG ◽  
KAI-PENG LIN ◽  
CHENG-I WENG
Keyword(s):  
Molecular Dynamics ◽  
Fracture Energy ◽  
Fracture Behavior ◽  
Tensile Loading ◽  
Md Simulations ◽  
Graphene Sheets ◽  
Dynamics Analysis ◽  
Fracture Characteristics ◽  
Effects Of Temperature ◽  
Loading Axis

Molecular dynamics (MD) simulations are performed to study the fracture behavior of armchair and zigzag graphene sheets with V-shaped notches subjected to tensile loading. The effects of temperature and notches depth on the fracture characteristics of the graphene sheets are examined. The results show that the cracks propagate from the notch tip along the direction perpendicular to the loading axis for armchair sheets. This is different from the zigzag graphene propagating along the direction of 45° from the loading axis. In addition, the fracture energy of zigzag graphene sheets is larger than armchair one at the same temperature condition.

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