Ductile Failure Predictions for the Three-Point Bending Test of a Complex Geometry Made From Aluminum Alloy

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Petr Kubík ◽  
František Šebek ◽  
Josef Zapletal ◽  
Jindřich Petruška ◽  
Tomáš Návrat

Abstract The ductile failure predictions have been an issue in many engineering applications. It begins with a design of machines and tools, continues with an evaluation of manufacturing processes, and last but not least ends with the assessment of various structures. The paper deals with a predictability of used criteria for a random structure of aluminum alloy 2024-T351, which was performed under the conditions of room temperature three-point bending. The bi-failure mode creates a space for the numerical studies of various approaches and gives an insight into the model performance. The plasticity was described by Lode-dependent yield criterion, which was coupled with several pressure and Lode-dependent fracture models to form a continuum damage mechanics approach via the material weakening. It was incorporated through a nonlinear damage accumulation, which was finally implemented using Fortran 77 subroutine into abaqus/explicit. All the models exhibited a good ability of crack onset prediction in terms of the force responses and realistic predictability of the crack propagation. The field of deformations was successfully compared with experimental data obtained by an optical method.

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5807
Author(s):  
Maciej Mogilski ◽  
Maciej Jabłoński ◽  
Martyna Deroszewska ◽  
Robert Saraczyn ◽  
Jan Tracz ◽  
...  

The aim of this study was to measure the energy absorbed by composite panels with carbon fiber-reinforced polymer (CFRP) skins and a 5052 aluminum alloy honeycomb core and to compare it to previous research and isotropic material—two 25 × 1.75 mm 1.0562 alloy steel tubes. The panel skins layup consisted of pre-impregnated Pyrofil TR30S 210 gsm 3K 2 × 2 twill oriented in directions 0/90 and −45/45 and having a consolidated thickness of 1 mm or 2 mm. The core consisted of a 15 mm or 20 mm honeycomb oriented along its lengthwise direction. The first test consisted of a three-point bending of specimens supported at a span of 400 mm with a 50 mm radius tubular load applicator in the middle. Second, a perimeter shear test was conducted using a 25 mm diameter punch and a 38 mm diameter hole. The results of the three-point bending test show that the energy absorbed by panels with 1 mm skins was similar to the energy absorbed by the tubes (96 J), which was better than the previously considered panels. In the case of perimeter shear, the average maximum forces for the top and bottom skin were 5.7 kN and 6.6 kN, respectively. For the panel with thicker skins (2 mm), the results were about 2 times higher.


2012 ◽  
Vol 560-561 ◽  
pp. 973-978 ◽  
Author(s):  
Jun Hang Guo ◽  
Ri Ichi Murakami ◽  
Sheng Dun Zhao

There are many models and failure criteria have been developed to predict the ductile fracture (DF) in metal plastic deformation. But usually, it is difficult to select a suitable model and the corresponding criterion from them. So, finding a way to identity their applicability and reliability is useful for selecting these DF criteria. In this paper, ductile fracture of aluminum alloy A5052P-H34 is studied by experiments and finite element simulations. In experiments, the mode I crack was obtained by uniaxial tension of plate with a circular hole in the center. The von Mises yield model and continuum damage mechanics based Rousselier model and modified Rousselier model are chosen to describe the material behavior. Three failure criteria, including the Cockcroft-Latham integral, maximum shear stress theory and critical void volume fraction criterion are investigated to determine their reliability in ductile failure prediction. These constitutive models and DF criteria are implemented by user material subroutine in ABAQUS/Explicit to predict the crack. And the crack initiation and propagation is implemented by element erosion method. By comparing the experiments and simulations, the modified Rousselier’s model with the corresponding criterion shows agreement with the experiments.


Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1723 ◽  
Author(s):  
Krzysztof Peliński ◽  
Jerzy Smardzewski

The work concerns a three-point bending test of beams made of plywood, high density fibre boards, cardboard, and wood-epoxy mass. The goal of the investigation was to determine the effect of thickness and type of wood-based facings on stiffness, strength, ability to absorb, and dissipate the energy of sandwich beams with an auxetic core. The cognitive goal of the work was to demonstrate the possibility of using recycled materials for facings and cores instead of popular wood composites. Experimental studies and numerical calculations were performed on correctly calibrated models. Experimental studies have shown that the beams with HDF facings (E = 1528 MPa, MOR = 12.61 MPa) and plywood facings (E = 1248–1395 MPa, MOR = 8.34–10.40 MPa) have the most favourable mechanical properties. Beams with plywood facings also have a good ability to absorb energy (1.380–1.746 J), but, in this respect, the beams manufactured of HDF (2.223 J) exhibited better capacity. The use of an auxetic core and facings of plywood and cardboard significantly reduces the amount of dissipated energy (0.0093 J, 0.0067 J). Therefore, this type of structures can be used for modeling beams carrying high deflections.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2450
Author(s):  
Andreas Borowski ◽  
Christian Vogel ◽  
Thomas Behnisch ◽  
Vinzenz Geske ◽  
Maik Gude ◽  
...  

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.


2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák

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.


2021 ◽  
Vol 55 ◽  
pp. 1114-1121
Author(s):  
Daniel Jindra ◽  
Zdeněk Kala ◽  
Jiří Kala ◽  
Stanislav Seitl

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3795
Author(s):  
Fernando Suárez ◽  
Jaime C. Gálvez ◽  
Marcos G. Alberti ◽  
Alejandro Enfedaque

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.


2015 ◽  
Vol 732 ◽  
pp. 85-90
Author(s):  
Lukáš Bek ◽  
Radek Kottner ◽  
Jan Krystek ◽  
Tomáš Kroupa

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.


2013 ◽  
Vol 486 ◽  
pp. 283-288
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek

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.


2016 ◽  
Vol 837 ◽  
pp. 198-202
Author(s):  
Luboš Pazdera ◽  
Libor Topolář ◽  
Tomáš Vymazal ◽  
Petr Daněk ◽  
Jaroslav Smutny

The aim of the paper is focused on the analysis of the mechanical properties of the concrete specimens with plasticizer at three point bending test by the signal analysis of the acoustic emission signal. The evaluations were compared the measurement and the results obtained with theoretical presumptions. The Joint Time Frequency Analysis applied on measurement data and its evaluation is described. It is well known that the Acoustic Emission Method is a very sensitive method to determine active cracks into structure. However, evaluation of acoustic emission signals is very difficult. A non-traditional method was used to signal analysis of burst acoustic emission signals recorded during three point bending test.


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