A Mathematical Solution for Calculating the Springback of Laminated Beech Stacks Molded within the Elastic Range

The springback effect in molded wood laminations within the elastic range has, to date, not yet been mathematically described. Once cured, residual internal stresses within the laminations cause the final form to deviate from that of the die. Test pieces of beech laminations of 1 mm, 2 mm and 4 mm thicknesses and stack sizes of between 2 and 16 laminations were used. The elasticity value of each stack was obtained using non-glued laminations in a three-point bending test within the elastic region. The laminations were glued with polyurethane resin and mounted in a radius form die. The stress induced by the die onto the stack is within the elastic region of the material without any prior chemical or physical plasticisation of the wood. After curing was complete and the laminations removed from the die, the actual radius was calculated using a circular equation within the CAD program, using three measurement points taken from the stack. The radius of the die within the limits of this study has a negligible effect when predicting the springback of the stack. The exponential correlation between springback and the number of laminations, was used to calculate the springback effect on molded laminated stacks.

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Homogeneous Pinus sp. particle boards reinforced with laminated composite materials

Engenharia Agrícola ◽

10.1590/1809-4430-eng.agric.v36n3p558-565/2016 ◽

2016 ◽

Vol 36 (3) ◽

pp. 558-565 ◽

Cited By ~ 4

Author(s):

André L. Christoforo ◽

Maria F. do Nascimento ◽

Tulio H. Panzera ◽

Sérgio L. M Ribeiro Filho ◽

Francisco A. R. Lahr

Keyword(s):

Composite Materials ◽

Castor Oil ◽

Mechanical Performance ◽

Laminated Composite ◽

Laminated Plates ◽

Modulus Of Rupture ◽

Bending Test ◽

Three Point Bending ◽

Polyurethane Resin ◽

Laminated Composite Materials

ABSTRACT This study aimed to evaluate the mechanical performance of laminated composite materials (fiberglass, carbon, sisal, palm fiber) in epoxy matrix as reinforcement in wood particleboards of Pinus sp. with bicomponent polyurethane resin from castor oil. Modulus of elasticity (MOE) and modulus of rupture (MOR) were investigated using a three-point bending test. Single-layered laminated plates were used to reinforce traction of specimens obtained from boards. MOE and MOR of materials developed without reinforcements exceeded limits in ABNT standards both NBR 12810-2:2002 and A208.1:199, proving therefore their feasibility. In all investigated cases, inclusion of reinforcements led to higher values for both MOE and MOR. Composites in fiberglass presented the best results.

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Preferential Orientation Dependent Mechanical and Electrical Properties in Naβ-Alumina Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.301.147 ◽

2006 ◽

Vol 301 ◽

pp. 147-150 ◽

Cited By ~ 2

Author(s):

Akira Kishimoto ◽

Kousei Shimokawa

Keyword(s):

Ionic Conductivity ◽

Mechanical Strength ◽

Hot Pressing ◽

Bending Test ◽

Two Dimensional ◽

Mechanical Reliability ◽

Alumina Ceramics ◽

Three Point Bending ◽

Mechanical And Electrical Properties ◽

Test Pieces

Nab-alumina is a two- dimensional ionic conductor in which conducting planes of Na+ ion are separated by insulating spinel block layers. For practical use, Nab- alumina needs not only high ionic conductivity but also mechanical reliability. Therefore, we prepared preferentially oriented Nab-alumina ceramics by hot pressing and evaluated the ionic conductivity and mechanical strength. The ionic conductivity perpendicular to the c-axis-oriented plane was five times higher than that parallel to c-axis. From the preferentially oriented Nab-alumina ceramics three types of test pieces were cut for a three-point bending test. In one type of test piece, the longest side was parallel to the hot-pressing direction, while the longest sides were perpendicular to that direction in the other types of test pieces. The latter test pieces showed mechanical strength 1.5 times that of the former.

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

Materials ◽

10.3390/ma14092450 ◽

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1100.152 ◽

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.

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

Transportation Research Procedia ◽

10.1016/j.trpro.2021.07.183 ◽

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

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

Materials ◽

10.3390/ma14143795 ◽

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.

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Experimental and Numerical Investigation of Critical Buckle Load of Composite Specimens

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.732.85 ◽

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.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.486.283 ◽

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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Three-Point Bending Test Evaluation of Concrete Specimens by Non-Traditional Analysis of Acoustic Emission Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.837.198 ◽

2016 ◽

Vol 837 ◽

pp. 198-202

Author(s):

Luboš Pazdera ◽

Libor Topolář ◽

Tomáš Vymazal ◽

Petr Daněk ◽

Jaroslav Smutny

Keyword(s):

Acoustic Emission ◽

Signal Analysis ◽

Measurement Data ◽

Bending Test ◽

Test Evaluation ◽

Acoustic Emission Method ◽

Emission Method ◽

Three Point Bending ◽

Time Frequency ◽

Emission Signal

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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