Determining Young’s modulus of timber on the basis of a strength database and stress wave propagation velocity I: an estimation method for Young’s modulus employing Monte Carlo simulation

2010 ◽  
Vol 56 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Mariko Yamasaki ◽  
Yasutoshi Sasaki
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Wave Propagation ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Estimation Method ◽  
Stress Wave Propagation ◽  
Wave Propagation Velocity ◽  
Stress Wave Propagation Velocity ◽  
Strength Database

scholarly journals A coupling model based on grey relational analysis and stepwise discriminant analysis for wood defect area identification by stress wave

BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1171-1186
Author(s):  
Xin Li ◽  
Wei Qian ◽  
Liting Cheng ◽  
Lihong Chang
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Propagation Velocity ◽  
Wood Specimen ◽  
Coupling Model ◽  
Stress Wave Propagation ◽  
Sectional Area ◽  
Wave Propagation Velocity ◽  
Cross Sectional ◽  
Stress Wave Propagation Velocity

Based on the experimental idea of reverse simulation, a quantitative area of hole was excavated at the sectional center of a wood specimen. The excavation area was 1/32S, 1/16S, 1/8S, 1/4S, and 1/2S (where S represents cross-sectional area of the complete specimen) and stress wave nondestructive testing of six sensors was performed. The stress wave propagation paths were statistically summarized to obtain the stress wave propagation velocity (Va) for two adjacent sensors, the stress wave propagation velocity (Vb) for two separated sensors, and the stress wave propagation velocity (Vc) for two opposite sensors. Furthermore, by analyzing the advantages and disadvantages of grey relation and stepwise discriminant model when both of them were used alone, a coupling model generated from them was established to dispose the test data. The attenuation ratios Ψa, Ψb, and Ψc of stress wave under three propagation paths and their relation ratios Va/Vb, Vb/Vc, and Va/Vc, a total of six groups of measured data, were selected as discriminant factors for the hole area grade of the wood specimen. The verification results showed that the discriminant accuracy of the coupling model was 100%, and it was concluded that the attenuation ratio (Ψb) of the stress wave propagation velocity for two separated sensors had the strongest discriminant ability against cross-sectional area of the specimen.

Improvement of Young's modulus and tensile strength of polymer impregnation and pyrolysis processed SiC/SiC composite by improved continuity of matrix

2004 ◽  
Vol 19 (8) ◽  
pp. 2377-2388 ◽  
Author(s):  
S. Ochiai ◽  
H. Okuda ◽  
S. Kimura ◽  
K. Morishita ◽  
M. Tanaka ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Tensile Strength ◽  
Monte Carlo ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Shear Lag ◽  
Pyrolysis Method ◽  
The Matrix ◽  
Barium Magnesium Aluminosilicate ◽  
Polymer Impregnation

Influences of the continuity of the matrix on Young's modulus and tensile strength of unidirectional SiC/SiC mini-composite prepared by the polymer impregnation and pyrolysis method were studied experimentally by observation of appearance of matrix and tensile test and analytically by a shear lag–Monte Carlo simulation. The continuity of the matrix was improved by the addition of particles such as ZrSiO4, barium magnesium aluminosilicate, and Pyrex (borosilicate glass) into the matrix. The improved continuity of the matrix led to the increase in stress carrying capacity of the matrix and therefore to the increase in Young's modulus and tensile strength of the composite. Such a correlation between the continuity of the matrix and the property of the composite was verified numerically by the shear lag–Monte Carlo simulation.

FEM Stress Analysis and Strength of Scarf Adhesive Joints of Similar Adherend Subjected to Impact Tensile Loadings

2007 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yuya Hirayama ◽  
He Dan
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Stress Wave ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Stress Wave Propagation ◽  
Adhesive Thickness ◽  
Three Dimensional Finite Element

The stress wave propagation and stress distribution in scarf adhesive joints have been analyzed using three-dimensional finite element method (FEM). The FEM code employed was LS-DYNA. An impact tensile loading was applied to the joint by dropping a weight. The effect of the scarf angle, Young’s modulus of the adhesive and adhesive thickness on the stress wave propagations and stress distributions at the interfaces have been examined. As the results, it was found that the point where the maximum principal stress becomes maximum changes between 52 degree and 60 degree under impact tensile loadings. The maximum value of the maximum principal stress increases as scarf angle decreases, Young’s modulus of the adhesive increases and adhesive thickness increases. In addition, Experiments to measure the strains and joint strengths were compared with the calculated results. The calculated results were in fairly good agreements with the experimental results.

Robustness of Residual Stresses in Castings and an Improved Process Window

2009 ◽  
Author(s):  
Magnus Hofwing ◽  
Niclas Stro¨mberg
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Thermal Expansion ◽  
Monte Carlo Simulations ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Young's Modulus ◽  
Process Window ◽  
Quadratic Response

In this work the robustness of residual stresses in finite element simulations with respect to deviations in mechanical parameters in castings is evaluated. Young’s modulus, the thermal expansion coefficient and the hardening are the studied parameters. A 2D finite element model of a stress lattice is used. The robustness is evaluated by comparing purely finite element based Monte Carlo simulations and Monte Carlo simulations based on linear and quadratic response surfaces. Young’s modulus, the thermal expansion coefficient and the hardening are assumed to be normal distributed with a standard deviation that is 10% of their nominal value at different temperatures. In this work an improved process window is also suggested to show the robustness graphically. By using this window it is concluded that least robustness is obtained for high hardening values in combination to deviations in Young’s modulus and the thermal expansion coefficient. It is also concluded that quadratic response surface based Monte Carlo simulations substitute finite element based Monte Carlo simulations satisfactory. Furthermore, the standard deviation of the responses are evaluated analytically by using the Gauss formula, and are compared to results from Monte Carlo simulations. The analytical solutions are accurate as long as the Gauss formula is not utilized close to a stationary point.

Three-Dimensional Finite Element Stress Response Analysis of Laminated Cantilever Beams With Adhesive Layers Subjected to Impact Loadings

1999 ◽  
Author(s):  
Jyo Shimura ◽  
Izumi Higuchi ◽  
Toshiyuki Sawa
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Stress Wave Propagation ◽  
Adhesive Interface ◽  
Number Of Layers ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract The stress behavior in adhesive laminated cantilever beams subjected to impact loadings is analyzed using three-dimensional finite-element method (FEM) in the elastic region. The stress wave propagation and the stress distribution at the interfaces are examined. The effects of Young’s modulus of adherends, adhesive, the adherend thickness and the number of layers on the stress wave propagation at the interfaces are clarified. The following results are obtained. The maximum principal stress (σ1) is maximal at the adhesive interfaces. It is found that the maximum principal stress (σ1) at the adhesive interface increases as the Young’s modulus of the upper adherends increases. The maximum principal stress (σ1) at the adhesive interface increases as Young’s modulus of the adhesive increases. The maximum principal stress (σ1) at the adhesive interface decreases as the thickness of the adherend to which an impact load is applied increases. It is seen that the maximum principal stress (σ1) increases as number of layers increases. Experiments were carried out to measure the strain response of adhesive laminated cantilever beam using strain gauges. A fairly good agreement is seen between the analytical and experimental results.

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