Bending and Contact Strength of Monolithic Ceramic Materials

2011 ◽  
Vol 21 (2) ◽  
pp. 293-305 ◽  
Author(s):  
Lucia Hegedűsová ◽  
Ladislav Ceniga ◽  
Ján Dusza
Keyword(s):  
Mechanical Loading ◽  
Ceramic Materials ◽  
Mechanical Tests ◽  
Bending Test ◽  
Weibull Analysis ◽  
Single Cycle ◽  
Contact Test ◽  
Four Point Bending ◽  
Four Point Bending Test

The article deals with the determination of strength of monolithic ceramic materials by mechanical tests, in bending and contact modes, simulated by a four-point bending test and single-cycle contact test using rollers or spheres, respectively. In general, the determination of strength of ceramic materials results from statistical methods, usually represented by the Weibull analysis comprising of the determination of the characteristic strength σ0 and the Weibull modulus m. Accordingly, the characteristic strength σ0,bend and σ0,cont as well as the Weibull moduli mbend and mcont, related to the four-point bending test and the single-cycle contact test using rollers, are determined, respectively. Additionally, the comparison of numerical results of σ0,bend/ σ0,cont, mbend/ mcont confirms the validity of the Fett's theory. Along with this verification and the Weibull analysis for mechanical loading by spheres, a microstructural analysis of strength-degrading defects as fraction origins is performed for the bending and contact modes which induce different types of crack. Finally, the determination of mechanical loading causing material failure and an analysis of parameters of the cracks is also presented. The mechanical tests were applied to monolithic Si3N4 and SiC ceramic materials.

Contact Strength and Cracking of Laminar Ceramics

2012 ◽  
Vol 31 (2) ◽  
Author(s):  
Lucia Hegedűsov’a ◽  
Ladislav Ceniga
Keyword(s):  
Statistical Methods ◽  
Ceramic Materials ◽  
Mechanical Tests ◽  
Bending Test ◽  
Contact Strength ◽  
Weibull Analysis ◽  
Single Cycle ◽  
Four Point Bending ◽  
Four Point Bending Test

AbstractThe paper deals with the determination of strength of laminar ceramics by mechanical tests in bending and contact modes. The bending and contact modes are simulated by the four-point bending test, and by single-cycle contact test using rollers or spheres, respectively. In general, the determination of strength of ceramic materials results from statistical methods which are usually represented by the Weibull analysis. The Weibull analysis comprises the determination of the characteristic strength

Contact and Bending Strength Tests of Ceramics: What is the Difference?

2009 ◽  
Vol 409 ◽  
pp. 185-192
Author(s):  
Lucia Hegedűsová ◽  
Alexandra Kovalčíková ◽  
Monika Kašiarová ◽  
Ján Dusza
Keyword(s):  
Bending Strength ◽  
Ceramic Materials ◽  
Contact Test ◽  
Four Point Bending ◽  
Sic Ceramic ◽  
Bending Mode ◽  
Strength Tests ◽  
The Difference

The paper deals with the determination of the characteristic strength and the Weibull modulus m of Si3N4 and SiC ceramic materials using conventional four-point bending and unconventional contact tests between opposite rollers and opposite spheres. Ceramographic and fractographic methods were used for the characterization of strength degrading defects represented by processing flaws and by cracks of different types arising during the loading. The processing flaws influenced the Weibull parameters mainly in the bending mode, and the strength and its scatter in contact modes was influenced by lateral, median and contact end cracks, originated during the contact test using rollers, and by cone cracks originated during the contact test using spheres.

scholarly journals Crushing of Double-Walled Corrugated Board and Its Influence on the Load Capacity of Various Boxes

2021 ◽  
Author(s):  
Tomasz Gajewski ◽  
Tomasz Garbowski ◽  
Natalia Staszak ◽  
Małgorzata Kuca
Keyword(s):  
Load Capacity ◽  
Shear Stiffness ◽  
Mechanical Tests ◽  
Torsional Stiffness ◽  
Bending Test ◽  
Corrugated Board ◽  
Four Point Bending ◽  
Residual Thickness ◽  
Flexographic Printing ◽  
Four Point Bending Test

As long as the non-contact digital printing is not a common standard in the corrugated packaging industry, corrugated board crushing is a real issue that affects the load capacity of the boxes. Crushing mainly occurs during the converting of corrugated board (e.g. analog flexographic printing or laminating) and is a process that cannot be avoided. However, as show in this study, it can be controlled. In this work, extended laboratory tests were carried out on the crushing of double-walled corrugated board. The influence of fully controlled crushing (with a precision: ±10 μm) in the range from 10 to 70 % on different laboratory measurements was checked. Most of the typical mechanical tests were performed e.g. edge crush test, four-point bending test, shear stiffness test, torsional stiffness test, etc. on reference and crushed specimens. The residual thickness reduction of the crushed samples was also controlled. All empirical observations and performed measurements were the basis for building an analytical model of crushed corrugated board. The proven and verified model was then used to study the crushing effect of the selected corrugated board on the efficiency of simple packages with various dimensions.

Testing of Concrete and Fibre Reinforced Concrete in Uniaxial Tension

2015 ◽  
Vol 1106 ◽  
pp. 49-52
Author(s):  
Martin Tipka ◽  
Jitka Vašková
Keyword(s):  
Reinforced Concrete ◽  
Uniaxial Tension ◽  
Direct Analysis ◽  
Bending Test ◽  
Strain Diagram ◽  
Fibre Reinforced Concrete ◽  
Four Point Bending ◽  
Deformation Parameters ◽  
Four Point Bending Test

The paper deals with an investigation of tensile properties of concrete and fibre reinforced concrete using the test in uniaxial tension. This arrangement is technically more difficult compared to the commonly used bending test, but allows easier determination of strength-deformation parameters of material. The advantage of the test is the possibility of direct analysis of the post-peak part of the stress-strain diagram in tension. The article describes the recommended test arrangement and analyzes methodology of loading. Attention is focused on the critical phase of the loading process and subsequent evaluation of results. In the experimental research was compared strength and corresponding strain of specific fibre reinforced concrete, obtained in three-point and four-point bending test, and the uniaxial tension test. The results of this comparative study are presented in the conclusion.

Bending and Contact Strength of a Ceramic Nanocomposite

2009 ◽  
Vol 417-418 ◽  
pp. 761-764
Author(s):  
Ján Dusza ◽  
Lucia Hegedűsová ◽  
Monika Kašiarová ◽  
Erika Csehová
Keyword(s):  
Microstructural Analysis ◽  
Bending Test ◽  
Material Failure ◽  
Contact Loading ◽  
Four Point Bending ◽  
Different Dimensions ◽  
Processing Defects ◽  
Four Point Bending Test ◽  
Stable Growth

The paper deals with the determination of the characteristic strength and as well as the Weibull moduli and of the Si3N4+SiC micro/nanocomposite determined by the four-point bending test and the contact test using opposite spheres both applied to specimens of different size, respectively. Material failure in the bending and contact modes is caused by the presence of processing defects as fracture origins, and by the formation of cone cracks, respectively, where a stable growth of the cone cracks initiated during contact loading is assumed to be a reason of , . A microstructural analysis of the processing flaws, and a mathematical analysis of the propagation of the cone cracks regarding different dimensions of a specimen are also presented.

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