Two Different Loading Directions to Determine the Shear and Longitudinal Modulus of Elasticity

Abstract Sitka spruce (Picea sitchensis) is the most widely planted commercial tree species in the United Kingdom and Ireland. Because of the increasing use of this species for construction, the ability to predict wood stiffness is becoming more important. In this paper, a number of models are developed using data on cellulose abundance and orientation obtained from the SilviScan-3 system to predict the longitudinal modulus of elasticity (MOE) of small defect-free specimens. Longitudinal MOE was obtained from both bending tests and a sonic resonance technique. Overall, stronger relationships were found between the various measures of cellulose abundance and orientation and the dynamic MOE obtained from the sonic resonance measurements, rather than with the static MOE obtained from bending tests. There was only a moderate relationship between wood bulk density and dynamic MOE (R2=0.423), but this relationship was improved when density was divided by microfibril angle (R2=0.760). The best model for predicting both static and dynamic MOE involved the product of bulk density and the coefficient of variation in the azimuthal intensity profile (R2=0.725 and 0.862, respectively). The model parameters obtained for Sitka spruce differed from those obtained in earlier studies on Pinus radiata and Eucalyptus delegatensis, indicating that the model might require recalibration before it can be applied to different species.

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Evaluation of Longitudinal Modulus of Elasticity in Wood Species for Structural Application

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.192 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 192-195

Author(s):

Eduardo Chahud ◽

Luiz Antônio Melgaço Nunes Branco ◽

André Luis Christoforo ◽

Francisco Antonio Rocco Lahr ◽

Rosane Aparecida Gomes Battistelle ◽

...

Keyword(s):

Wood Species ◽

Modulus Of Elasticity ◽

Mechanical Test ◽

Font Size ◽

Bending Tests ◽

Structural Application ◽

Longitudinal Elastic Modulus ◽

Longitudinal Modulus ◽

Dipteryx Odorata ◽

Brazilian Standard

1024x768 This research aimed to investigate possible differences in values of longitudinal modulus of elasticity for wood species usually employed for structural purposes, as Castanheira (Bertholletia excelsa), Cambará (Erisma uncinatum), Cumaru (Dipteryx odorata), Jatobá (Hymenaea stilbocarpa), Garapa (Apuleia leiocarpa) and Peroba Rosa (Aspidosperma polyneuron), obtained from compression and tension parallel to grain, and static bending tests. Recommendations of the Brazilian standard ABNT NBR 7190:1997, Annex B, were followed. Statistical analysis results for the cited properties, had equivalent averages for the six wood species analyzed. This confirms that any of the three tests can be used to obtain the longitudinal elastic modulus and which could avoid the necessity of evaluating stiffness values for wood by more than one kind of mechanical test. Normal 0 21 false false false PT-BR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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Evaluating a Test Parameter in Static Bending for Pinus sp. Wood

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.196 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 196-199

Author(s):

Elen Aparecida Martines Morales ◽

Helder Kenzo Kondo ◽

Juliana Cortez Barbosa ◽

Cristiane Inácio de Campos ◽

Francisco Antonio Rocco Lahr ◽

...

Keyword(s):

Shear Stress ◽

Cross Section ◽

Modulus Of Elasticity ◽

Nonlinear Behavior ◽

Pinus Elliottii ◽

Vertical Deflection ◽

Test Parameter ◽

Bending Tests ◽

Paulo State ◽

Longitudinal Modulus

Abstract. The study aimed to analyze the longitudinal modulus of elasticity (Em), based on static bending tests, in different spans and confirm that it’s necessary adopt as 21 the ratio between span and height of the cross section of the specimen to turn no significant the influence of shear stress on vertical deflection. So, simplified equation to determine Emcan be employed. Specimens ofPinus elliottiivar.elliottiiandPinus elliottiivar. elliottii×Pinus cariabeaehondurensis(hybrid), came from Itapeva region, São Paulo State, Brazil, were considered. Bending tests were conducted in Labs of Experimental Campus Itapeva, UNESP, adapting recommendations of Brazilian Code ABNT NBR 7190. Twelve specimens of each species were tested. The trend lines for the plotted graphics showed clearly a nonlinear behavior until the neighborhood of ratio 21 and no expressive variations after this point, confirming that normative recommendations are correct.

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Mechanical Properties of Hydroxyapatite Doped with Magnesium, Used in Bone Implants

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.430.222 ◽

2013 ◽

Vol 430 ◽

pp. 222-229 ◽

Cited By ~ 1

Author(s):

Oana Suciu ◽

Teodora Ioanovici ◽

Liviu Bereteu

Keyword(s):

Mechanical Properties ◽

Thermal Stability ◽

Modulus Of Elasticity ◽

Mechanical Characteristics ◽

Precipitation Method ◽

Bone Implants ◽

Wet Precipitation ◽

Longitudinal Modulus

Hydroxyapatite is a biomaterial, more exactly a bioceramic, from a category of materials frequently used in bone implants. In order to improve mechanical properties, hydroxyapatite is doped with different chemical substitutes, among which the most used are: Mg2*, Zn 2*, La3*, Y3*, In3* Bi3* CO32-, Si and Mn. In the paper are presented the modality of obtaining hydroxyapatite doped with magnesium through wet precipitation method and also the determination of its main mechanical characteristics. There is also an analysis on the effects of magnesium on the following mechanical properties: density, hardness, longitudinal modulus of elasticity, conductibility and thermal stability.

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