Adaptive Zooming Method for the Simulation of Quasi-Brittle Materials

2015 ◽  
Vol 784 ◽  
pp. 284-291
Author(s):  
Antoine Llau ◽  
Ludovic Jason ◽  
Julien Baroth ◽  
Frédéric Dufour
Keyword(s):  
Brittle Material ◽  
Concrete Structures ◽  
Brittle Materials ◽  
Nonlinear Computation

A method to simulate concrete structures (quasi-brittle material) with localized nonlinearities is presented. Based on Guyan’s condensation, it consists in replacing the elastic zones of the structure by their equivalent rigidities (super-elements). The nonlinear computation is then performed only on the zones of interest (ie, damaged). As new damaged zones may appear, the proposed method monitors the evolution of the system and re-integrates previously condensed areas if necessary. This method, applied on different tests cases, allows a substantial computation economy.

Schleifen von WC-Co-Hartmetallen*/Grinding of Cemented Carbides (WC-Co)

2016 ◽  
Vol 106 (06) ◽  
pp. 374-379
Author(s):  
C. Wirtz ◽  
F. Vits ◽  
P. Mattfeld ◽  
F. Prof. Klocke
Keyword(s):  
Brittle Material ◽  
Brittle Materials ◽  
Material Behavior ◽  
Ductile Material ◽  
Cemented Carbides ◽  
Multi Phase

Beim Schleifen mehrphasiger Werkstoffe mit sprödhartem Charakter, beispielsweise Hartmetall, wurde ein Übergang von sprödhartem zu duktilem Werkstoffverhalten nachgewiesen. Der Fachartikel stellt eine neu entwickelte Methodik zur systematischen Analyse des Zerspanverhaltens – im Speziellen den Übergang von vorwiegend duktilem zu überwiegend sprödhartem Zerspanverhalten – für Hartmetalle vor.   In grinding of multi-phase, brittle materials, e. g. cemented carbides, a transition from predominantly brittle to predominantly ductile material behavior has been proven scientifically. This paper presents a newly developed methodology to analyze the material behavior of cemented carbides, in particular the transition from ductile to brittle material behavior.

scholarly journals Дестабилизация внедрения высокоскоростной струи в хрупких материалах

2019 ◽  
Vol 89 (5) ◽  
pp. 685
Author(s):  
Б.В. Румянцев
Keyword(s):  
Brittle Material ◽  
High Speed ◽  
Bending Strength ◽  
Brittle Materials ◽  
Absorption Efficiency ◽  
Hydrodynamic Approximation ◽  
Metal Jet

AbstractThe results of penetration of a high-speed metal jet (with a velocity of 3–7 km/s) into brittle materials (ceramics and glass) have been analyzed. The data on jet destabilization as a result of the response of the brittle material to the high-speed penetration are presented. The generalized dependence of the high-speed jet absorption efficiency on the bending strength of the brittle material has been constructed in the hydrodynamic approximation.

Ductile-Regime Machining for Fast Tool Servo Diamond Turning of Micro-Structured Surfaces on Brittle Materials

2012 ◽  
Vol 500 ◽  
pp. 333-338 ◽  
Author(s):  
De Ping Yu ◽  
Yoke San Wong ◽  
Geok Soon Hong
Keyword(s):  
Experimental Investigation ◽  
Brittle Material ◽  
Brittle Materials ◽  
Diamond Turning ◽  
Fast Tool Servo ◽  
Entire Surface ◽  
Structured Surfaces ◽  
Simulation Based ◽  
Ductile Regime Machining ◽  
Machining Characteristics

Micro-structured surfaces on brittle materials, e.g. ceramic and glass, are gaining increasing application in a range of areas. In this paper, fast tool servo (FTS) diamond turning has been applied to machine micro-structured surfaces on brittle materials and the machined surfaces has been observed to study its machining mechanism. A machining model is presented to enable ductile-regime machining of the brittle material. Based on the model, machining characteristics can be predicted for given cutting conditions. Experimental investigation on machining of a micro-structured surface verified that ductile-regime machining can be ensured on the entire surface through path planning simulation based on the machining model.

scholarly journals Damage Function of a Quasi-Brittle Material, Damage Rate, Acceleration and Jerk during Uniaxial Compression: Model and Application to Analysis of Trabecular Bone Tissue Destruction

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1759
Author(s):  
Gennady Kolesnikov
Keyword(s):  
Trabecular Bone ◽  
Bone Tissue ◽  
Uniaxial Compression ◽  
Brittle Material ◽  
Brittle Materials ◽  
Practical Interest ◽  
Damage Function ◽  
Rate Acceleration ◽  
Damage Process ◽  
Trabecular Bone Tissue

A diversity of quasi-brittle materials can be observed in various engineering structures and natural objects (rocks, frozen soil, concrete, ceramics, bones, etc.). In order to predict the condition and safety of these objects, a large number of studies aimed at analyzing the strength of quasi-brittle materials has been conducted and presented in publications. However, at the modeling level, the problem of estimating the rate and acceleration of destruction of a quasi-brittle material under loading remains relevant. The purpose of the study was to substantiate the function of damage to a quasi-brittle material under uniaxial compression, determine the rate, acceleration and jerk of the damage process, and also to apply the results obtained to predicting the destruction of trabecular bone tissue. In accordance with the purpose of the study, the basic concepts of fracture mechanics and standard methods of mathematical modeling were used. The proposed model is based on the application of the previously obtained differentiable damage function without parameters. The results of the study are presented in the form of plots and analytical relations for computing the rate, acceleration and jerk of the damage process. Examples are given. The predicted peak of the combined effect of rate, acceleration and jerk of the damage process are found to be of practical interest as an additional criterion for destruction. The simulation results agree with the experimental data known from the available literature.

Modeling Material Removal in Fracture Erosion for Brittle Materials by Abrasive Waterjet

2009 ◽  
Vol 76-78 ◽  
pp. 357-362 ◽  
Author(s):  
Hong Tao Zhu ◽  
Chuan Zhen Huang ◽  
Jun Wang ◽  
Guo Qun Zhao ◽  
Quan Lai Li
Keyword(s):  
Brittle Material ◽  
Material Removal ◽  
Brittle Materials ◽  
Abrasive Waterjet ◽  
Abrasive Waterjet Machining ◽  
Waterjet Machining ◽  
Modeling Material ◽  
Ceramic Glass ◽  
Material Removal Model ◽  
Removal Model

The abrasive waterjet machining is a powerful tool in processing various materials, especially, for brittle materials, such as ceramic, glass and so on. However, the material removal of a brittle material when impacted by abrasive waterjet is not understood in detail. In this paper, the material removal model in fracture erosion of brittle materials by abrasive waterjet has been developed.

Ductile Mode Turning of Brittle Materials and its Practical Aspects

2013 ◽  
Vol 651 ◽  
pp. 350-354 ◽  
Author(s):  
Alokesh Pramanik ◽  
Animesh Basak
Keyword(s):  
Tool Wear ◽  
Ultrasonic Vibration ◽  
Tool Life ◽  
Brittle Material ◽  
Laser Heating ◽  
Brittle Materials ◽  
Machining Time ◽  
Main Obstacle ◽  
Ductile Machining ◽  
Ductile Mode

This paper aims to investigate the mechanism of ductile machining of brittle material based on information available in the literature. It also explores the challenges associated with the ductile machining of brittle materials which stop the technology from being applied in practical fields. In addition, few factors that assist to improve productivity of ductile machining of brittle material have been discussed. It is found the higher tool wear is the main obstacle of this technology. The application ofmicro-laser heating,ultrasonic vibration and coolants improve the machining time and tool life significantly.

Breaking Process Modeling Using FEM – Proposition of a Method for Identification of Material Data and for Identification Features Job Contact

2014 ◽  
Vol 1036 ◽  
pp. 592-597
Author(s):  
Jarosław Mańkowski
Keyword(s):  
Compression Test ◽  
Brittle Material ◽  
Process Modeling ◽  
Complex Structure ◽  
Brittle Materials ◽  
Contact Problems ◽  
Good Convergence ◽  
Material Parameters ◽  
Properties Of Materials ◽  
The Impact

Brittle materials belong to the group of brittle materials with a very complex structure. As heterogeneous and anisotropic materials, are randomly distributed discontinuity structures such as scratches, cracks, pores. One of the problems, which often occurs during the analysis, is to identify the properties of materials data and identify the characteristics of the impact of the tool on a brittle material. This paper presents a method of identification of material parameters and a method of modelling the contact problems for limestone Morawica. Tests and analyzes were performed for a roller compression test. Very good convergence of the results of analysis and of the results of an experiment performed on a real object was obtained.

Analysis of Effect of Crack in Composite Beam on Slip of Shear Connectors

2013 ◽  
Vol 405-408 ◽  
pp. 925-928
Author(s):  
Wan Heng He ◽  
Qing Hua Gu ◽  
Ying Chen Ma ◽  
Xin Hua Ni ◽  
Xiang Feng Meng
Keyword(s):  
Mechanical Properties ◽  
Full Advantage ◽  
Brittle Material ◽  
Composite Beam ◽  
Brittle Materials ◽  
Second Order ◽  
Ductile Materials ◽  
Shear Connectors ◽  
Ultimate Moment

Composite beam takes full advantage of mechanical properties of brittle and ductile materials elements. The key point is to rely on the shear connectors ensure overall coordination of composite beam, so as to achieve the effect of flexural component. The crack in composite beam caused by brittle materials elements is not negligible. We obtained the slip of shear connectors with the second order precision under the conditions that there are cracks in the brittle material elements, and the ultimate moment is obtained too.

scholarly journals Brittle materials at high-loading rates: an open area of research

2017 ◽  
Vol 375 (2085) ◽  
pp. 20160436 ◽  
Author(s):  
Pascal Forquin
Keyword(s):  
Strain Rate ◽  
High Strain ◽  
Concrete Structures ◽  
Brittle Materials ◽  
Impact Testing ◽  
High Loading ◽  
Strain Rates ◽  
High Strain Rates ◽  
Loading Rates ◽  
Complex Features

Brittle materials are extensively used in many civil and military applications involving high-strain-rate loadings such as: blasting or percussive drilling of rocks, ballistic impact against ceramic armour or transparent windshields, plastic explosives used to damage or destroy concrete structures, soft or hard impacts against concrete structures and so on. With all of these applications, brittle materials are subjected to intense loadings characterized by medium to extremely high strain rates (few tens to several tens of thousands per second) leading to extreme and/or specific damage modes such as multiple fragmentation, dynamic cracking, pore collapse, shearing, mode II fracturing and/or microplasticity mechanisms in the material. Additionally, brittle materials exhibit complex features such as a strong strain-rate sensitivity and confining pressure sensitivity that justify expending greater research efforts to understand these complex features. Currently, the most popular dynamic testing techniques used for this are based on the use of split Hopkinson pressure bar methodologies and/or plate-impact testing methods. However, these methods do have some critical limitations and drawbacks when used to investigate the behaviour of brittle materials at high loading rates. The present theme issue of Philosophical Transactions A provides an overview of the latest experimental methods and numerical tools that are currently being developed to investigate the behaviour of brittle materials at high loading rates. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’.

scholarly journals A Numerical Simulation of Effects of Softening and Heterogeneity on the Stress Intensity Factor of Quasi-Brittle Material

2014 ◽  
Vol 6 ◽  
pp. 586472 ◽  
Author(s):  
Tielin Chen ◽  
Chao Li ◽  
Dingli Zhang
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Brittle Material ◽  
Fracture Behavior ◽  
Brittle Materials ◽  
Numerical Approach ◽  
Crack Initiation And Propagation ◽  
Nonlinear Fracture ◽  
Initiation And Propagation

A numerical approach to simulate the crack initiation and propagation process of the nonlinear fracture behavior of the quasi-brittle materials under tensile loading is presented. The nonlinear fracture of Mode I of quasi-brittle material is analyzed by considering the effects of microscopic softening rate and heterogeneity. The results show that the softening rate and the heterogeneity of quasi-brittle material affect the values of stress intensity factor K I. The softening index affects merely the size of the plastic zones while the heterogeneity causes the more sophisticated response of quasi-brittle materials.

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