Mechanical and Non-Destructive Testing of Plasterboards Subjected to a Hydration Process

The aim of this study was to investigate the effect of plasterboards’ humidity absorption on their performance. Specimens’ hydration procedure consisted of consecutive immersing in water and subsequent drying at room temperature. Such a procedure was performed to increase the content of moisture within the material volume. The microstructural observations of five different plasterboard types were performed through optical and scanning electron microscopy. The deterioration of their properties was evaluated by using a three-point bending test and a subsequent ultrasonic (ultrasound testing (UT)) longitudinal wave velocity measurement. Depending on the material porosity, a loss of UT wave velocity from 6% to 35% and a considerable decrease in material strength from 70% to 80% were observed. Four types of approximated formulae were proposed to describe the dependence of UT wave velocity on board moisture content. It was found that the proposed UT method could be successfully used for the on-site monitoring of plasterboards’ hydration processes.

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Grading of structural timber of Populus × euramericana clone I-214

Holzforschung ◽

10.1515/hf-2011-0153 ◽

2012 ◽

Vol 66 (5) ◽

pp. 633-638 ◽

Cited By ~ 17

Author(s):

Milagros Casado ◽

Luis Acuña ◽

Luis-Alfonso Basterra ◽

Gemma Ramón-Cueto ◽

Daniel Vecilla

Keyword(s):

High Strength ◽

Bending Test ◽

Non Destructive Testing ◽

Destructive Testing ◽

Visual Grading ◽

Populus Euramericana ◽

Four Point Bending ◽

Low Elastic Modulus ◽

Non Destructive

Abstract Grading tests were performed on 338 poplar wood samples (Populus × euramericana I-214) with dimensions of 150×50 mm2, 150×80 mm2, and 200×100 mm2 prepared for structural utilization. The non-destructive testing methods included ultrasound (Sylvatest) and induced vibrations (Portable Lumber Grader) combined with visual grading criteria. Additionally, screw withdrawal resistance was tested by the instrument Fakopp. These results were compared with those obtained by a four-point bending test according to the EN 408 (2004) standard. Ultrasound and induced vibrations overestimated the quality of this type of wood. Correlation equations are proposed to determine the true characteristics for each testing method. It can be concluded that poplar timber from clone I-214 has acceptable flexural strength, but a comparatively low elastic modulus, whereby it is not graded within a high strength class according to the EN 338 (2009) standard.

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Alternative methodology for calculating the modulus of elasticity of wooden beams of structural dimensions

Engenharia Agrícola ◽

10.1590/s0100-69162014000100016 ◽

2014 ◽

Vol 34 (1) ◽

pp. 153-160 ◽

Cited By ~ 5

Author(s):

André L. Christoforo ◽

Tulio H. Panzera ◽

Carlito Calil Neto Junior ◽

Mauro A. Demarzo ◽

Sérgio L. M. Ribeiro Filho ◽

...

Keyword(s):

Modulus Of Elasticity ◽

Least Squares Method ◽

Bending Test ◽

Non Destructive Testing ◽

Destructive Testing ◽

Response Variable ◽

Structural Dimensions ◽

Calculation Methodology ◽

Alternative Methodology ◽

Non Destructive

This study aims to present an alternative calculation methodology based on the Least Squares Method for determining the modulus of elasticity in bending wooden beams of structural dimensions. The equations developed require knowledge of three or five points measured in displacements along the piece, allowing greater reliability on the response variable, using the statistical bending test at three points and non-destructively, resulting from imposition of measures from small displacements L/300 and L/200, the largest being stipulated by the Brazilian norm NBR 7190:1997. The woods tested were Angico, Cumaru, Garapa and Jatoba. Besides obtaining the modulus of elasticity through the alternative methodology proposed, these were also obtained employing the Brazilian norm NBR 7190:1997, adapted to the condition of non-destructive testing (small displacements) and for pieces of structural dimensions. The results of the modulus of elasticity of the four species of wood according to both calculation approaches used proved to be equivalent, implying the good approximation provided by the methodology of calculation adapted from the Brazilian norm.

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Material Strength Evaluation and Damage Detection by X-Ray Diffraction

Advances in X-ray Analysis ◽

10.1154/s0376030800009174 ◽

1991 ◽

Vol 35 (A) ◽

pp. 489-501

Author(s):

Toru Goto

Keyword(s):

Damage Detection ◽

Crystalline Structure ◽

Material Strength ◽

Non Destructive Testing ◽

X Ray Diffraction ◽

Destructive Testing ◽

Strength Evaluation ◽

X Ray ◽

Surface Observation ◽

Non Destructive

AbstractThe number of products that have to be inspected in pre-service and/or in service is increasing. Not only inspection for flaws are required increasingly, using the ordinary non-destructive testing, but also inspection of material characteristics, such as material strength evaluation and/or damage detection. For such inspection, X-ray diffraction has great possibilities as one of the most promising techniques, because it is (a) noncontact, (b) very sensitive to changes in parameters of the crystalline structure, and (c) suitable for surface observation.In this paper, three topics are introduced which will be useful in the field of material strength evaluation and damage detection using X-ray diffraction.

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Comparison of Sandstone Damage Measurements Based on Non-Destructive Testing

Materials ◽

10.3390/ma13225154 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5154

Author(s):

Duohao Yin ◽

Qianjun Xu

Keyword(s):

Elastic Modulus ◽

Wave Velocity ◽

Damage Variable ◽

The Other ◽

P Wave ◽

Non Destructive Testing ◽

Destructive Testing ◽

P Wave Velocity ◽

Amplitude Attenuation ◽

Non Destructive

Non-destructive testing (NDT) methods are an important means to detect and assess rock damage. To better understand the accuracy of NDT methods for measuring damage in sandstone, this study compared three NDT methods, including ultrasonic testing, electrical impedance spectroscopy (EIS) testing, computed tomography (CT) scan testing, and a destructive test method, elastic modulus testing. Sandstone specimens were subjected to different levels of damage through cyclic loading and different damage variables derived from five different measured parameters—longitudinal wave (P-wave) velocity, first wave amplitude attenuation, resistivity, effective bearing area and the elastic modulus—were compared. The results show that the NDT methods all reflect the damage levels for sandstone accurately. The damage variable derived from the P-wave velocity is more consistent with the other damage variables, and the amplitude attenuation is more sensitive to damage. The damage variable derived from the effective bearing area is smaller than that derived from the other NDT measurement parameters. Resistivity provides a more stable measure of damage, and damage derived from the acoustic parameters is less stable. By developing P-wave velocity-to-resistivity models based on theoretical and empirical relationships, it was found that differences between these two damage parameters can be explained by differences between the mechanisms through which they respond to porosity, since the resistivity reflect pore structure, while the P-wave velocity reflects the extent of the continuous medium within the sandstone.

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Application of the Non-Destructive Testing Method to Determine the Gmax of Bangkok Clay

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.418.157 ◽

2013 ◽

Vol 418 ◽

pp. 157-160 ◽

Cited By ~ 1

Author(s):

Keeratikan Piriyakul

Keyword(s):

Shear Wave ◽

Wave Velocity ◽

Field Test ◽

Shear Wave Velocity ◽

Non Destructive Testing ◽

Bender Element ◽

Destructive Testing ◽

Testing Method ◽

Bender Element Test ◽

Non Destructive

This article presents the application of the non-destructive testing method (so called Bender element test) to measure the shear wave velocity and determine the maximum shear modulus of soft Bangkok clay samples. This research proposes the bender element technique to measure the shear wave velocity by means of piezoelectric ceramic sensors. The details of the bender element test were clearly explained. The laboratory bender element test data of the shear wave velocity were compared with the field test results and show that the field propagating waves pass along layers of higher stiffness while the laboratory test data were performed on small, possible less stiff material. The inversion calculation of the shear wave velocity in the field test is based on a linear elastic isotropic assumption which is not valid for the Bangkok subsoil and might be a second reason for the noticed differences in velocity.

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Quality Assessment of Strengthened Concrete by FRP Laminates using Non-Destructive Testing

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.c5170.029320 ◽

2020 ◽

Vol 9 (3) ◽

pp. 1179-1188

Keyword(s):

Wave Velocity ◽

Concrete Beams ◽

Plain Concrete ◽

P Wave ◽

Flexural Behavior ◽

Non Destructive Testing ◽

Destructive Testing ◽

P Wave Velocity ◽

Externally Bonded ◽

Non Destructive

A non-destructive testing program has been designed to evaluate the integrity of the bond strength of plain concrete beams strengthened by Glass Fiber Reinforced Polymer (GFRP) Laminates. A series of concurrent static load and non-destructive testing experiments were carried out in the materials and testing laboratory at the college of engineering, Mataria, Helwan University, Cairo, Egypt. A total of 90 plain concrete standard beam specimens of dimensions 150 mm x 150 mm x 750 mm were constructed in the laboratory with three different design strength categories (38, 45, and 50) MPa. The beam specimens were strengthened by externally bonded GFRP laminates with various number of layers namely (3, 5 and 7) layers. In addition, the effect of debonding of the GFRP laminates was investigated by simulating it by variation in voids between concrete and laminates namely, (0, 30 and 60%). This study investigates the effectiveness of externally bonded GFRP laminates on the flexural strength of plain concrete beams by using Ultrasonic Pulse Velocity (UPV) device before and during loading until failure and their effect on the p-wave velocities. Four-point flexural tests were performed on the concrete beams, strengthened with different layouts of GFRP laminates and different percentage of voids at the concrete-laminate interface. The capacity of the beams and p-wave velocity were investigated. It was found that as the percentage of voids decreased, the capacity of strengthened concrete beams increased linearly. The reduction in voids enhanced the beam flexural behavior and controlled tension crack propagation. In addition, it was observed that use of GFRP laminates were more effective with higher concrete characteristic strength provided that debonding is not present. Finally, it was evident that the UPV technique was successful in detecting the variation in concrete p-wave velocity with strength and laminate layers variation.

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Correlation between Crack Growth Rate and Magnetic Memory Signal of X45 Steel

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.2293 ◽

2007 ◽

Vol 353-358 ◽

pp. 2293-2296 ◽

Cited By ~ 3

Author(s):

Hai Yan Xing ◽

Ri Xin Wang ◽

Min Qiang Xu ◽

Jia Zhong Zhang

Keyword(s):

Growth Rate ◽

Crack Growth Rate ◽

Crack Growth ◽

Fatigue Testing ◽

Magnetic Memory ◽

Non Destructive Testing ◽

Destructive Testing ◽

Three Point Bending ◽

Growth Evaluation ◽

Non Destructive

Crack growth rate, as an important parameter, is widely applied in crack growth evaluation and fatigue life prediction. The objective of this paper is to study crack growth rate with the metal magnetic memory (MMM) technology which is a non-destructive testing method newly developed. The correlation between crack growth rate da / dN and magnetic memory signal Hp(y) is investigated through three-point bending fatigue testing. Samples of steel X45, with different heat treatments, quenching and thermal refining, are tested in HYG fatigue machinery. The correlation curves of da / dN ~ Hp(y) are built and the characteristics of magnetic memory signal are given. The influence of heat treatment on Hp(y) is also analyzed. The crack growth rate model of X45 based on MMM signal is presented and verified.

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