scholarly journals Impact of dampness to changes in the mechanical properties of solid fired bricks

2021 ◽  
Vol 1209 (1) ◽  
pp. 012036
Author(s):  
V Bartoň ◽  
J Šnédar ◽  
P Cikrle
Keyword(s):  
Mechanical Properties ◽  
Regression Models ◽  
Natural Frequencies ◽  
Resonance Method ◽  
Record Values ◽  
Ultrasonic Waves ◽  
Historic Buildings ◽  
Fired Bricks ◽  
Non Destructive ◽  
Passage Times

Abstract This work deals with the monitoring of changes in the mechanical properties of solid fired bricks depending on their dampness using non-destructive methods. Decreases of first natural frequencies by the resonance method and increase of passage times of ultrasonic waves depending on increasing dampness are monitored. The elements were firstly fully saturated and then slowly dried so that it was possible to record the values of the first natural frequencies and the passage times of the ultrasonic waves at different dampness. It is not possible to record values in all dampness, so the measured values were interpolated by regression models. A polynomial of the 2nd degree seems to be the most suitable. Dampness corresponding to the minimum natural frequencies and the maximum passage times of the ultrasonic waves were performed on these regression models. This research is the first step in determining the durability criteria for ceramic products, especially solid fired bricks. In the future, durability criteria should help in the reconstruction of historic buildings to assess whether the element that will be exposed to the weather is durable or not. These tests are completely non-destructive, which means that the tested element can be subsequently used in construction.

scholarly journals LONG-TIME INVESTIGATION OF CEMENT PASTES WITH MICRONIZED OLD CONCRETE, INFLUENCE OF DIFFERENT TYPE OF MIXING APPROACH ON MECHANICAL PROPERTIES

2020 ◽  
Vol 26 ◽  
pp. 71-75
Author(s):  
Zdeněk Prošek ◽  
Pavel Tesárek
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Resonance Method ◽  
Dynamic Shear Modulus ◽  
Cement Composites ◽  
Cement Pastes ◽  
Long Time ◽  
The Individual ◽  
The Impact ◽  
Non Destructive

The article focuses on the impact of different type of mixing approach on resulting mechanical properties of cement composites. The monitored parameters of the mixing approach were the speed of mixing and the method of mixing the individual components of the fresh mixture. The mechanical properties of the resulting composites were the main comparative parameter. The determined mechanical properties were dynamic modulus of elasticity, dynamic shear modulus, flexural strength and compressive strength. Dynamics moduli were detected using non-destructive resonance method during the whole experiment and compressive and flexural strength were determined by destructive method for 28 and 129 days old samples. Testing samples had dimensions equal to 40×40×160 mm.

Composite Material Based on Cement and PVA: Evolution of Mechanical Properties during First 28 Days

2014 ◽  
Vol 1054 ◽  
pp. 215-220 ◽  
Author(s):  
Martin Lidmila ◽  
Pavel Tesárek ◽  
Tomáš Plachy ◽  
Zdeněk Prošek ◽  
Václav Nežerka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Resonance Method ◽  
Cement Pastes ◽  
Shear Moduli ◽  
Curing Conditions ◽  
Laboratory Environment ◽  
Non Destructive ◽  
Common Laboratory

The aim of the presented study was to find a relationship between PVA concentration and properties of cement pastes. The PVA solution was added into fresh mortar in the amount equal to 1.4 and 2.8 % of cement weight. The produced samples were consequently stored in different curing conditions – exposed to air in common laboratory environment or submerged in water. The development of the dynamic Young’s and shear moduli was monitored using the non-destructive resonance method during first 28 days of hardening. The obtained data were compared to the measurements of a pure cement reference paste.

Effect of Microfillers on Selected Destructive and Nondestructive Mechanical Properties of Cement Mortars: Different Types of Recycled Materials

2016 ◽  
Vol 722 ◽  
pp. 195-200
Author(s):  
Tomáš Plachý ◽  
Pavel Tesárek ◽  
Lukáš Hlubocký ◽  
Jaromír Hrůza ◽  
Jozef Fládr ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Resonance Method ◽  
Recycled Concrete ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Measuring Device ◽  
Cement Mortars ◽  
Marble Powder ◽  
Non Destructive

The paper presents the use of non-destructive testing to determine the evolution of mechanical properties. For testing, we used the resonance method. The measuring device of company Brüel&Kjær was used. Specifically, evolution of dynamic modulus of elasticity (determined from the longitudinal and transverse vibration) and the shear modulus was determined for the first 28 days after production of the samples. The results of non-destructive method were also used for verifying the relevance of the results of destructive testing, specifically the results of the compressive strength and a three-point flexural strength. Testing of mechanical properties was performed on samples of cement mortars, where the micronized recycled concrete and micronized marble powder were used as microfillers, both materials were prepared on a high-speed mill of the Lavaris company (Czech Republic).

Influence of Recycled Materials on Resulting Mechanical Properties of Cement Composites

2016 ◽  
Vol 825 ◽  
pp. 53-56
Author(s):  
Zdeněk Prošek ◽  
Jaroslav Topič ◽  
Jan Trejbal ◽  
Karel Šeps ◽  
Pavel Tesárek
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Resonance Method ◽  
Recycled Concrete ◽  
Silica Sand ◽  
Destructive Testing ◽  
Recycled Materials ◽  
High Speed Grinding ◽  
Marble Powder ◽  
Non Destructive

This article presents the mechanical properties of composite materials based on recycled materials which differ in their composition – type of recycled materials. Dynamic modulus of elasticity was monitored during the first 28 days since manufacture by use of non-destructive testing (resonance method). Flexural strength and compressive strength were determined for the 28 days old specimens. The aim of this article was to determine the influence of type and amount of recycled material on the resulting mechanical properties. Mixtures with 3 different microground materials (recycled concrete, marble powder and silica sand) were tested. Microground materials were produced in the company Lavaris (Czech Republic) by use of high speed grinding. The results obtained from these materials were compared with reference material – cement mortar.

scholarly journals Mechanical Properties of Sandstone using non-Destructive Method

2020 ◽  
Vol 241 ◽  
pp. 113
Author(s):  
H. Rajaoalison ◽  
A. Zlotkowski ◽  
G. Rambolamanana
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Ultrasonic Waves ◽  
Effect Of Temperature ◽  
Drilling Process ◽  
Wellbore Instability ◽  
S Waves ◽  
Coefficient Corrélation ◽  
Rock Parameters ◽  
Non Destructive

The understanding of physical and mechanical properties of rock is considered as critical in drilling, geo-engineering, and construction applications. As an example, the awareness of these rock parameters contributes to avoid or minimizing instability around the wellbore while drilling. The laboratory experiment of understanding of these parameters can be done in two-different ways: static, where the sample subjects to destruction after the test and dynamic, known as non-destruction method. The non-destructive method using ultrasonic waves under a series of different stress conditions, starting from 7 to 56 MPa with incrementation of 7MPa, has been used in this paper in order to characterize the mechanical properties of dry Zbylutów sandstone at 20 and 80°C. The velocity of primary (P) and secondary (S) waves within these ranges has been recorded in order to understand the behavior of the mechanical properties. The results showed that the Young’s modulus, bulk modulus, shear modulus, and Lame’s constant of Zbylutów sandstone have a positive correlation with good coefficient correlation with the increased stress, while the Poisson’s ratio showed a negative correlation. Besides, the effect of temperature on the rock parameters is approved by the decrease of primary wave velocity in this two-different temperature range. Such results are necessary when preparing the appropriate mud weight for drilling process, which is related to wellbore instability.  

Failure Analysis of Flip-Chip Interconnections Through Acoustic Microscopy

1996 ◽  
Author(s):  
O. Diaz de Leon ◽  
M. Nassirian ◽  
C. Todd ◽  
R. Chowdhury
Keyword(s):  
Failure Analysis ◽  
Large Scale ◽  
Flip Chip ◽  
Ultrasonic Waves ◽  
Acoustic Microscopy ◽  
Acoustic Microscope ◽  
Chip Technology ◽  
Ball Joints ◽  
Non Destructive ◽  
Scanning Acoustic Microscope

Abstract Integration of circuits on semiconductor devices with resulting increase in pin counts is driving the need for improvements in packaging for functionality and reliability. One solution to this demand is the Flip- Chip concept in Ultra Large Scale Integration (ULSI) applications [1]. The flip-chip technology is based on the direct attach principle of die to substrate interconnection.. The absence of bondwires clearly enables packages to become more slim and compact, and also provides higher pin counts and higher-speeds [2]. However, due to its construction, with inherent hidden structures the Flip-Chip technology presents a challenge for non-destructive Failure Analysis (F/A). The scanning acoustic microscope (SAM) has recently emerged as a valuable evaluation tool for this purpose [3]. C-mode scanning acoustic microscope (C-SAM), has the ability to demonstrate non-destructive package analysis while imaging the internal features of this package. Ultrasonic waves are very sensitive, particularly when they encounter density variations at surfaces, e.g. variations such as voids or delaminations similar to air gaps. These two anomalies are common to flip-chips. The primary issue with this package technology is the non-uniformity of the die attach through solder ball joints and epoxy underfill. The ball joints also present defects as open contacts, voids or cracks. In our acoustic microscopy study packages with known defects are considered. It includes C-SCAN analysis giving top views at a particular package interface and a B-SCAN analysis that provides cross-sectional views at a desired point of interest. The cross-section analysis capability gives confidence to the failure analyst in obtaining information from a failing area without physically sectioning the sample and destroying its electrical integrity. Our results presented here prove that appropriate selection of acoustic scanning modes and frequency parameters leads to good reliable correlation between the physical defects in the devices and the information given by the acoustic microscope.

Measurement of Young’s Modulus and Shear Modulus of Some Structures Welded Using Flux Cored Wire by Vibration Tests

2014 ◽  
Vol 216 ◽  
pp. 151-156 ◽  
Author(s):  
Liviu Bereteu ◽  
Mircea Vodǎ ◽  
Gheorghe Drăgănescu
Keyword(s):  
Shear Modulus ◽  
Arc Welding ◽  
Natural Frequencies ◽  
Free Vibrations ◽  
Vibration Modes ◽  
Cored Wire ◽  
Flux Cored Arc Welding ◽  
Longitudinal Elastic Modulus ◽  
Vibration Tests ◽  
Non Destructive

The aim of this work was to determine by vibration tests the longitudinal elastic modulus and shear modulus of welded joints by flux cored arc welding. These two material properties are characteristic elastic constants of tensile stress respectively torsion stress and can be determined by several non-destructive methods. One of the latest non-destructive experimental techniques in this field is based on the analysis of the vibratory signal response from the welded sample. An algorithm based on Pronys series method is used for processing the acquired signal due to sample response of free vibrations. By the means of Finite Element Method (FEM), the natural frequencies and modes shapes of the same specimen of carbon steel were determined. These results help to interpret experimental measurements and the vibration modes identification, and Youngs modulus and shear modulus determination.

Influence of the applied pressure of the transducer on the propagation speed of the ultrasonic wave in wood

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Edgar V.M. Carrasco ◽  
Rejane C. Alves ◽  
Mônica A. Smits ◽  
Vinnicius D. Pizzol ◽  
Ana Lucia C. Oliveira ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Applied Pressure ◽  
Pressure Gauge ◽  
Eucalyptus Grandis ◽  
Propagation Speed ◽  
Ultrasonic Waves ◽  
Ultrasonic Speed ◽  
Wave Propagation Speed ◽  
Propagation Technique ◽  
Non Destructive

Abstract The non-destructive wave propagation technique is used to estimate the wood’s modulus of elasticity. The propagation speed of ultrasonic waves is influenced by some factors, among them: the type of transducer used in the test, the form of coupling and the sensitivity of the transducers. The objective of the study was to evaluate the influence of the contact pressure of the transducers on the ultrasonic speed. Ninety-eight tests were carried out on specimens of the species Eucalyptus grandis, with dimensions of 120 × 120 × 50 mm. The calibration of the pressure exerted by the transducer was controlled by a pressure gauge using a previously calibrated load cell. The robust statistical analysis allowed to validate the experimental results and to obtain consistent conclusions. The results showed that the wave propagation speed is not influenced by the pressure exerted by the transducer.

Vibration-Based Crack Detection in L-Frames

2014 ◽  
Vol 658 ◽  
pp. 261-268
Author(s):  
Jean Louis Ntakpe ◽  
Gilbert Rainer Gillich ◽  
Florian Muntean ◽  
Zeno Iosif Praisach ◽  
Peter Lorenz
Keyword(s):  
Strain Energy ◽  
Crack Detection ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Structural Elements ◽  
Element Analysis ◽  
Accurate Localization ◽  
Mathematical Expressions ◽  
Measurement Results ◽  
Non Destructive

This paper presents a novel non-destructive method to locate and size damages in frame structures, performed by examining and interpreting changes in measured vibration response. The method bases on a relation, prior contrived by the authors, between the strain energy distribution in the structure for the transversal vibration modes and the modal changes (in terms of natural frequencies) due to damage. Using this relation a damage location indicator DLI was derived, which permits to locate cracks in spatial structures. In this paper an L-frame is considered for proving the applicability of this method. First the mathematical expressions for the modes shapes and their derivatives were determined and simulation result compared with that obtained by finite element analysis. Afterwards patterns characterizing damage locations were derived and compared with measurement results on the real structure; the DLI permitted accurate localization of any crack placed in the two structural elements.

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