Planar shear moduli of rigidity of an oriented strand board from bending and shear tests

2004 ◽  
Vol 37 (7) ◽  
pp. 480-484 ◽  
Author(s):  
W. H. Thomas
Keyword(s):  
Oriented Strand Board ◽  
Shear Tests ◽  
Shear Moduli ◽  
Planar Shear

A new device for planar shear tests on wood-based panels

1997 ◽  
Vol 30 (10) ◽  
pp. 634-639
Author(s):  
N. Baldassino ◽  
P. Zanon ◽  
R. Zanuttini
Keyword(s):  
Shear Tests ◽  
New Device ◽  
Planar Shear

Equivalent viscoelastic solids for heterogeneous fluid-saturated porous rocks

Geophysics ◽  
2009 ◽  
Vol 74 (1) ◽  
pp. N1-N13 ◽  
Author(s):  
J. Germán Rubino ◽  
Claudia L. Ravazzoli ◽  
Juan E. Santos
Keyword(s):  
Monte Carlo ◽  
Seismic Waves ◽  
Fluid Pressure ◽  
Porous Rocks ◽  
Quality Factors ◽  
Shear Tests ◽  
Viscoelastic Solids ◽  
Shear Moduli ◽  
Phase Velocities ◽  
Biot’S Equations

Different theoretical and laboratory studies on the propagation of elastic waves in real rocks have shown that the presence of heterogeneities larger than the pore size but smaller than the predominant wavelengths (mesoscopic-scale heterogeneities) may produce significant attenuation and velocity dispersion effects on seismic waves. Such phenomena are known as “mesoscopic effects” and are caused by equilibration of wave-induced fluid pressure gradients. We propose a numerical upscaling procedure to obtain equivalent viscoelastic solids for heterogeneous fluid-saturated rocks. It consists in simulating oscillatory compressibility and shear tests in the space-frequency domain, which enable us to obtain the equivalent complex undrained plane wave and shear moduli of the rock sample. We assume that the behavior of the porous media obeys Biot’s equations and use a finite-element procedure to approximate the solutions of the associated boundary value problems. Also, because at mesoscopic scales rock parameter distributions are generally uncertain and of stochastic nature, we propose applying the compressibility and shear tests in a Monte Carlo fashion. This facilitates the definition of average equivalent viscoelastic media by computing the moments of the equivalent phase velocities and inverse quality factors over a set of realizations of stochastic rock parameters described by a given spectral density distribution. We analyzed the sensitivity of the mesoscopic effects to different kinds of heterogeneities in the rock and fluid properties using numerical examples. Also, the application of the Monte Carlo procedure allowed us to determine the statistical properties of phase velocities and inverse quality factors for the particular case of quasi-fractal heterogeneities.

scholarly journals On anisotropic mechanical properties of heterogeneous magnetic polymeric composites

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180212 ◽  
Author(s):  
Dmitry Borin ◽  
Gennady Stepanov ◽  
Eike Dohmen
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
External Field ◽  
Axial Loading ◽  
Homogeneous Magnetic Field ◽  
Field Application ◽  
Direction Parallel ◽  
Shear Moduli ◽  
Planar Shear ◽  
Anisotropic Mechanical Properties

This study is devoted to the magneto-mechanical characterization of heterogeneous magnetoactive elastomers based on an elastic polydimethylsiloxane matrix with embedded spherical magnetic soft microparticles and magnetic hard microparticles of irregular shape. An issue of the anisotropic mechanical properties of these smart composites is considered. Non-magnetized and pre-magnetized specimens are characterized using a planar shear and axial loading in an externally applied homogeneous magnetic field. The field direction differs relative to the direction of the field used for the specimens pre-magnetization. Results of the different methods allow comparison of the tensile shear moduli for the samples with an initially identical composition. Obtained results demonstrate a strong correlation between the composite behaviour and orientation of the magnetic field used for the pre-magnetization of the sample relative to the external field applied to a sample during the test. Composites pre-magnetized in the direction parallel to an applied mechanical force and external magnetic field show higher magnetorheological response than composites pre-magnetized transversally to the force and the field. Application of the external field directed opposite to the direction of the pre-magnetization reduces the observed stiffening. Moreover, in this situation a softening of the material can be observed, depending on the magnitude of the external field and the field used for pre-magnetization. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

scholarly journals Comparison of methods for determining shear modulus of wood

2020 ◽  
Vol 78 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Robert Krüger ◽  
André Wagenführ
Keyword(s):  
European Beech ◽  
Torsion Test ◽  
Test Methods ◽  
Orthotropic Materials ◽  
Shear Tests ◽  
Shear Moduli ◽  
Linear Elastic ◽  
Frame Method ◽  
Square Plate ◽  
Picture Frame

Abstract In this study, the relatively new picture frame method applied to wood is compared with three established shear test methods, namely the experimental modal analysis, the square plate twist method and the torsion test. For the investigations, the wood species European beech (Fagus sylvatica L.) and spruce (Picea abies L. Karst.) were used and the shear tests were conducted in LR and RL direction. The results show comparable shear moduli for beech and spruce in the range of 931–1289 Nmm−2 and 495–842 Nmm−2, respectively. In contrast to the theory of linear elastic orthotropic materials, significant differences in the results of the picture frame method between LR and RL direction were observed for spruce.

Understanding the effect of weathering on adhesive bonds for wood composites using digital image correlation (DIC)

Holzforschung ◽  
2019 ◽  
Vol 73 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Paige McKinley ◽  
Arijit Sinha ◽  
Frederick A. Kamke
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Failure Load ◽  
Image Correlation ◽  
Wood Composites ◽  
Shear Tests ◽  
Adhesive Bonds ◽  
Shear Moduli ◽  
Lap Shear

Abstract The quality of wood composites is dependent on the bondlines’ performance and their moisture resistance. The effect of moisture intrusion into bondlines is the focus of this study. The strain profile in the bondline during loading was investigated and the effects of weathering on the bondline were quantified by digital image correlation (DIC), while load deflection data were collected from lap-shear tests (LShTs). A total of 75 LShTs were evaluated including four different adhesive types with Douglas-fir wood, out of which 39 served as controls and 36 as substrates for weathering. The effect of weathering on failure load was not statistically significant. Only the bonded surface and adhesive type have significant effects on failure load, as well as the three-way interaction between the bonded surface, adhesive, and weathering, as revealed by three-way analysis of variance (ANOVA). The average effective shear moduli for the weathered samples were significantly lower than those for the control samples.

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