Second-Order Computational Homogenization Approach Using Higher-Order Gradients at Microlevel

2015 ◽  
Vol 665 ◽  
pp. 181-184 ◽  
Author(s):  
Tomislav Lesičar ◽  
Zdenko Tonković ◽  
Jurica Sorić
Keyword(s):  
Heterogeneous Material ◽  
Computational Homogenization ◽  
Second Order ◽  
Material Behavior ◽  
Bending Test ◽  
Present Contribution ◽  
Three Point Bending ◽  
Linear Elastic ◽  
Homogenization Approach ◽  
Realistic Description

Realistic description of heterogeneous material behavior demands more accurate modeling at macroscopic and microscopic scales. To observe strain localization phenomena and material softening occurring at the microstructural level, an analysis on the microlevel is unavoidable. Multiscale techniques employing several homogenization schemes can be found in literature. Widely used second-order homogenization requiresC1continuity at the macrolevel, while standardC0continuity has usually been hold at microlevel. However, due to theC1-C0transition macroscale variables cannot be defined fully consistently. The present contribution is concerned with a multiscale second-order computational homogenization employingC1continuity at both scales under assumptions of small strains and linear elastic material behavior. All algorithms derived are implemented into the FE software ABAQUS. The numerical efficiency and accuracy of the proposed computational strategy is demonstrated by modeling three point bending test of the notched specimen.

Measure of Nonlocal Response in Multiscale Gradient Modeling

2016 ◽  
Vol 713 ◽  
pp. 297-300
Author(s):  
Tomislav Lesičar ◽  
Zdenko Tonković ◽  
Jurica Sorić
Keyword(s):  
Multiple Scales ◽  
Gradient Elasticity ◽  
Heterogeneous Material ◽  
Second Order ◽  
Material Behavior ◽  
Successful Development ◽  
Macroscopic Fracture ◽  
Realistic Description ◽  
Gradient Elasticity Theory ◽  
Gradient Modeling

Realistic description of heterogeneous material behavior demands more accurate modeling at multiple scales. Multiscale scheme employing second-order homogenization requires C1 continuity at the macrolevel, while classical continuum is usually kept at the microlevel (C1-C0 homogenization). However, due to C1-C0 transition, consistency of macroscale variables is violated. This research proposes a new second-order homogenization scheme employing C1 continuity at both scales. Discretization is performed by the C1 finite element and Aifantis gradient elasticity theory. A new gradient boundary conditions are derived. The relation between the Aifantis length scale and the RVE size has been found. The new procedure is tested on a benchmark example. After successful development of the C1-C1 multiscale scheme, the next step is an extension to consistent scaling of the microscale strain localization towards a macroscopic fracture.

scholarly journals Determination of Stress Intensity Factor Value for Chevron-Notched Specimens – Pilot Study

2017 ◽  
Vol 17 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Jakub Sobek ◽  
Stanislav Seitl
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Material Behavior ◽  
Bending Test ◽  
Layer Width ◽  
Test Configuration ◽  
Three Point Bending ◽  
Loading Mode ◽  
Chevron Notch

Abstract The description of material behavior is one of important information for its application in civil engineering. One area is covering fracture mechanical properties. For evaluation of the fracture toughness values, the knowledge of calibration curve is important. The paper is aimed on the numerical modelling of the test specimens with a chevron notch serving as an initiator of the stress distribution at the crack tip. The three-point bending test configuration with a chevron notch is used for the simulation given by plane model with different layer width of cross section part and output is given by the value of the stress intensity factor KI for tension loading mode.

scholarly journals The Viscoelasticity Model of Corn Straw under the Different Moisture Contents

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Sun Zhong-Zhen ◽  
Jiang Huan-Xin ◽  
Cai He-Ping ◽  
Yu Qiu-Sheng ◽  
Lu Li-Xin ◽  
...  
Keyword(s):  
Elastic Element ◽  
Viscoelastic Model ◽  
Bending Test ◽  
Corn Stalk ◽  
Corn Straw ◽  
Three Point Bending ◽  
Linear Elastic ◽  
Moisture Contents ◽  
Set Up ◽  
Nonlinear Elastic

Viscoelastic model of corn straw, based on different moisture contents, is set up to characterise the deformation through three-point bending test. The model contains a linear elastic element, a damping element, and a nonlinear elastic element. The parameters of the model are determined according to the features of three-point bending test curve and characteristic of the model. The relationships between mechanical properties, energy absorption behavior of corn stalk, and moisture content have been, respectively, analysed. And regression analysis and curve fitting have been conducted based on various parameters and moisture contents with Matlab. These parameters provide the basis for straw crushing equipment design.

scholarly journals Additive Manufacturing-Based In Situ Consolidation of Continuous Carbon Fibre-Reinforced Polycarbonate

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2450
Author(s):  
Andreas Borowski ◽  
Christian Vogel ◽  
Thomas Behnisch ◽  
Vinzenz Geske ◽  
Maik Gude ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fibre ◽  
Bending Test ◽  
Thermoplastic Composites ◽  
Experimental Investigations ◽  
Material Structure ◽  
Three Point Bending ◽  
Continuous Fibre ◽  
Local Material

Continuous carbon fibre-reinforced thermoplastic composites have convincing anisotropic properties, which can be used to strengthen structural components in a local, variable and efficient way. In this study, an additive manufacturing (AM) process is introduced to fabricate in situ consolidated continuous fibre-reinforced polycarbonate. Specimens with three different nozzle temperatures were in situ consolidated and tested in a three-point bending test. Computed tomography (CT) is used for a detailed analysis of the local material structure and resulting material porosity, thus the results can be put into context with process parameters. In addition, a highly curved test structure was fabricated that demonstrates the limits of the process and dependent fibre strand folding behaviours. These experimental investigations present the potential and the challenges of additive manufacturing-based in situ consolidated continuous fibre-reinforced polycarbonate.

Effect of Concrete Mixture Composition on Acoustic Emission and Fracture Parameters Obtained from Three-Point Bending Test

2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Mixture Composition ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

scholarly journals Experimental and Numerical simulation of a Three Point Bending Test of a Stainless Steel Beam

2021 ◽  
Vol 55 ◽  
pp. 1114-1121
Author(s):  
Daniel Jindra ◽  
Zdeněk Kala ◽  
Jiří Kala ◽  
Stanislav Seitl
Keyword(s):  
Numerical Simulation ◽  
Stainless Steel ◽  
Bending Test ◽  
Steel Beam ◽  
Three Point Bending

scholarly journals Fracture and Size Effect of PFRC Specimens Simulated by Using a Trilinear Softening Diagram: A Predictive Approach

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3795
Author(s):  
Fernando Suárez ◽  
Jaime C. Gálvez ◽  
Marcos G. Alberti ◽  
Alejandro Enfedaque
Keyword(s):  
Reinforced Concrete ◽  
Size Effect ◽  
A Priori ◽  
Plain Concrete ◽  
Specimen Size ◽  
Bending Test ◽  
Orientation Factor ◽  
Fibre Reinforced Concrete ◽  
Softening Function ◽  
Three Point Bending

The size effect on plain concrete specimens is well known and can be correctly captured when performing numerical simulations by using a well characterised softening function. Nevertheless, in the case of polyolefin-fibre-reinforced concrete (PFRC), this is not directly applicable, since using only diagram cannot capture the material behaviour on elements with different sizes due to dependence of the orientation factor of the fibres with the size of the specimen. In previous works, the use of a trilinear softening diagram proved to be very convenient for reproducing fracture of polyolefin-fibre-reinforced concrete elements, but only if it is previously adapted for each specimen size. In this work, a predictive methodology is used to reproduce fracture of polyolefin-fibre-reinforced concrete specimens of different sizes under three-point bending. Fracture is reproduced by means of a well-known embedded cohesive model, with a trilinear softening function that is defined specifically for each specimen size. The fundamental points of these softening functions are defined a priori by using empirical expressions proposed in past works, based on an extensive experimental background. Therefore, the numerical results are obtained in a predictive manner and then compared with a previous experimental campaign in which PFRC notched specimens of different sizes were tested with a three-point bending test setup, showing that this approach properly captures the size effect, although some values of the fundamental points in the trilinear diagram could be defined more accurately.

Experimental and Numerical Investigation of Critical Buckle Load of Composite Specimens

2015 ◽  
Vol 732 ◽  
pp. 85-90
Author(s):  
Lukáš Bek ◽  
Radek Kottner ◽  
Jan Krystek ◽  
Tomáš Kroupa
Keyword(s):  
Static Analysis ◽  
Glass Fibre ◽  
Large Deformations ◽  
Bending Test ◽  
Test Results ◽  
Beam Test ◽  
Three Point Bending ◽  
Box Beams ◽  
Buckle Beam ◽  
Thin Walled

Different carbon and glass fibre strips were subjected to the double clamp buckle beam test. Furthermore, thin-walled glass fibre box-beams were subjected to the three-point bending test. Results of experiments were compared to different numerical simulations using buckling analysis or static analysis considering large deformations.

Influence of Honeycomb Core Compression on the Mechanical Properties of the Sandwich Structure

2013 ◽  
Vol 486 ◽  
pp. 283-288
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek
Keyword(s):  
Mechanical Properties ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Low Velocity Impact ◽  
Bending Test ◽  
Honeycomb Core ◽  
Low Velocity ◽  
Three Point Bending ◽  
Core Technology

This research paper deals with an investigation of the influence of honeycomb core compression on the mechanical properties of sandwich structures. These structures consist of prepreg facing layers and two different material types of honeycomb and are produced by modified compression molding called Crush-Core technology. Produced structures are mechanically tested in three-point bending test and subjected to low-velocity impact and Charpy impact test.

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