The Use of Genetic Programming and Regression Analysis for Modeling the Modulus of Elasticity of NSC and HSC

Purpose The purpose of this paper is to study the influence of the porous structure on the maximum stress and modulus of elasticity of the specimens which are fabricated by rapid prototypes. According to the experimental results, modify the theoretical formula of elastic modulus. Design/methodology/approach The Objet Eden 250 was used to prepare the Vero White photosensitive resin samples with different porosity (ranges from 25 to 65 per cent) and different pore structures. The mechanical properties of different samples were numerically simulated and the formulas of the modulus of elasticity were established. Through the compression test, the performance of the specimen is compared and analyzed, and the theoretical elastic modulus formula is optimized. Findings With the increase of porosity, the maximum stress of honeycomb structure specimens decreases. The maximum stress of the honeycomb structure specimen with circular pore shape is higher than the hexagon cross-section while the hexahedron and octahedron structure are the arms (wall thickness between pores) with a square cross-section. The error comparison between the modulus of elasticity before and after the structure models regression analysis shows that after the regression analysis, the error of theoretical value and the actual value is between 0 and 14 per cent which is lower than the value before the regression analysis which was between 5 and 27 per cent. Originality/value The paper obtains rules of the influence of different porous structures which were fabricated by the Vero White photosensitive resin material on mechanical properties and higher prediction accuracy formula of elastic modulus. The conclusions provide a theoretical basis for Northeastern University, China, to reduce mass and mechanical properties prediction of load-bearing parts.

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The Effect of Knots on Bending Modulus of Elasticity of Dimension Lumber

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.517.677 ◽

2012 ◽

Vol 517 ◽

pp. 677-682

Author(s):

Yong Zhong ◽

Hai Qing Ren ◽

Wan Li Lou ◽

Xia Zhen Li

Keyword(s):

Regression Analysis ◽

Modulus Of Elasticity ◽

Multivariate Regression ◽

Predictive Accuracy ◽

Multivariate Regression Analysis ◽

Average Density ◽

Full Scale ◽

Bending Test ◽

Bending Modulus ◽

Dimension Lumber

The defects, especially for knot, seriously affect the bending properties of wood. In this paper, full scale specimens and clear specimens for bending test, cut from dimension lumbers of Larix gmelinii with different kinds of knots, aimed to predictive accuracy of the modulus of elasticity (MOE) in bending and to improve the accuracy of MOE by multivariate regression analysis with density and knot information. According to the regression analysis results, the [(IK/Ig)·(MK/Mo)] of all knots and the average density ρa showed the best predictive accuracy of MOE for full scale specimen (Efull), with 0.674 of R2 and 1.15 of RMSE. Based on the ratio of regression parameter B/A of independent variables for density and knots information, the knots had less influential than density on influencing Efull. Finally, a simplified theoretical model that can be used to calculate MOE for dimension lumber, was defined as Efull/Eclear = B[(IK/Ig)·(MK/Mo)]+C .

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Tensile Properties Study of Polyester/Cotton/Silk Tri-Component Sirofil Composite Yarn

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.331.129 ◽

2011 ◽

Vol 331 ◽

pp. 129-132

Author(s):

Li Bin Lv ◽

Mei Du

Keyword(s):

Regression Analysis ◽

Tensile Properties ◽

Modulus Of Elasticity ◽

Elasticity Modulus ◽

Linear Regression Analysis ◽

Element Model ◽

Experimental Result ◽

Composite Yarn ◽

Non Linear ◽

Large Distortion

The tensile properties of tri-component Sirofil composite yarn is analyzed. To characterize the stretchability of the composite yarn, a three-element model with little distortion has been established. It is concluded that the elasticity modulus can be improved when three single yarns with different modulus of elasticity are composited. Under this condition, the modulus of elasticity of the composite yarn is among the three. Furthermore, in order to describe the elongation of the composite yarn at break, a four-component dynamic model of drawing with large distortion is developed. And the results obtained are verified by non-linear regression analysis. It is demonstrated that the properties of non-linear visco-elasticity of sirofil composite yarn can be characterized by using multinomial and the curve plotted according to the experimental result is basically in agreement with that deduced by the theoretical model.

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Assessing the bending strength and modulus of elasticity in bending of exterior foiled plywoods in relation to their construction

Journal of Forest Science ◽

10.17221/4546-jfs ◽

2012 ◽

Vol 51 (No. 2) ◽

pp. 76-94

Author(s):

J. Hrázský ◽

P. Král

Keyword(s):

Mechanical Properties ◽

Regression Analysis ◽

Correlation Analysis ◽

Moisture Content ◽

Surface Treatment ◽

Modulus Of Elasticity ◽

Bending Strength ◽

Physical And Mechanical Properties ◽

Institutional Research ◽

The Given

The paper summarizes results of an institutional research aimed at assessing the bending strength and modulus of elasticity in bending of exterior foiled combined and all-beech plywoods in relation to their construction. A relationship was studied of the plywood construction and selected physical and mechanical properties. In studied sheets, moisture, density, bending strength and modulus of elasticity were analysed along and across the grain of the upper veneer. All measurements were carried out in water-resistant plywoods with surface treatment with a phenolformaldehyde foil 8, 10, 12 and 15 mm thick in combined plywoods and 10, 12, 15 and 18 mm thick in all-beech plywoods. The construction of plywoods significantly influences their quality that is determined particularly by the bending strength and modulus of elasticity. Using regression analysis relationships were demonstrated particularly that with the increasing moisture content of plywoods the bending strength decreased and with the increasing density the bending strength and modulus of elasticity increased. The same trend was also proved in connection with the increasing number of veneers of plywood sheets. Using correlation analysis, combinations of interrelationships of the given properties were statistically tested.

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