An Investigation of the Crack Tendency on Wood Surfaces After Different Machining Operations

Holzforschung ◽  
2000 ◽  
Vol 54 (4) ◽  
pp. 427-436 ◽  
Author(s):  
Micael Stehr ◽  
Sören Östlund
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Analysis ◽  
Annual Rings ◽  
The Finite Element Method ◽  
Crack Generation ◽  
Wood Piece ◽  
Idealised Model ◽  
Machining Operations ◽  
Wood Surfaces

Summary A hypothesis describing tip-crack generation during different machining operations on sapwood of pine surfaces and the differences between the pith side and bark side were investigated. The goal was to determine whether initial tip-cracks are generated already during the machining operation, before weathering. The evaluation of the results showed that about 10 % of the annual rings on the pith side and about 1% of the annual rings on the bark side have cracks after the machining operation. A theoretical analysis of an idealised model using the finite element method (FEM) has also been carried out to investigate the tendency for growth of short initial tip-cracks during a simulation of the compression of a wood piece in a conventional planing operation. The analysis seems to confirm that there is a greater risk for cracks on the pith side than on the bark side.

Research and Simulation on Drawing Force of the Tripod Type Universal Coupling

2012 ◽  
Vol 482-484 ◽  
pp. 792-795
Author(s):  
Ye Qiang Lu ◽  
Wen Feng Wei ◽  
Yi Long Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Analysis ◽  
Cross Section ◽  
The Finite Element Method ◽  
Drawing Force ◽  
Simulation Results ◽  
Universal Coupling ◽  
Castigliano’S Theorem ◽  
Static Simulation

Analyzing the strain expression referring to Castigliano’s Theorem after analysis of the tripod type universal coupling under drawing force comes to the simplified mode of tripod type universal coupling. And with the help of simplified mode, it concludes that the minimum strain occurs when the radius of cross-section of the circlip equals to the depth of groove. After setting material attributes, boundary conditions, contacts of the tripod type universal coupling, and static simulation with the finite element method in SolidWorks, the strain of the universal couplings is carried out. Theoretical analysis and simulation results show that when the radius of cross-section of the coupling equals to the depth of groove, the strain is minimum.

General Instability of Swedge-Stiffened Circular Cylinders Under Uniform External Pressure

1993 ◽  
Vol 37 (01) ◽  
pp. 77-85
Author(s):  
C. T. F. Ross ◽  
A. Palmer
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Finite Element ◽  
Theoretical Analysis ◽  
External Pressure ◽  
Reduction Factor ◽  
Circular Cylinders ◽  
The Finite Element Method ◽  
Uniform External Pressure ◽  
Thinness Ratio

A theoretical and experimental investigation into the general instability of nine swedge-stiffened circularcylinders under uniform external pressure is described. The investigation found that most of the vesselssuffered plastic general instability, and that initial out-of-roundness played a significant role in the magnitude of the elastic knockdown. The theoretical analysis was based on the finite-element method, and a thinness ratio is proposed from which one can determine a plastic reduction factor when more experimental results are available.

Vibration of Hemi-Ellipsoidal Axisymmetric Domes Submerged in Water

1986 ◽  
Vol 200 (6) ◽  
pp. 389-398 ◽  
Author(s):  
C T F Ross ◽  
T Johns
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Aspect Ratio ◽  
Theoretical Analysis ◽  
Shell Structure ◽  
The Finite Element Method ◽  
Axisymmetric Form ◽  
Different Types ◽  
Thin Walled ◽  
Theory And Experiment

Ten thin-walled domes, of hemi-ellipsoidal form, were vibrated in air and while partially and fully submerged in water. The domes varied in shape from oblate ones of aspect ratio (AR) 0.25 to prolate ones of aspect ratio 4. The fundamental modal patterns for the oblate domes tended to be of axisymmetric form, while the fundamental modal patterns of the hemispherical and prolate domes tended to be of asymmetric or lobar form. The theoretical analysis was carried out by the finite element method, where the motion of the shell structure was represented by three different types of element and the motion of the water was represented by a solid annular element. Comparison between theory and experiment was found to be good.

Study of the Torsional Effect of a Rectangular Quartz Disc

2011 ◽  
Vol 474-476 ◽  
pp. 2286-2289
Author(s):  
Chang Yin Gao ◽  
Wan Quan Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Field ◽  
Theoretical Analysis ◽  
Anisotropic Elasticity ◽  
Electromagnetic Theory ◽  
The Finite Element Method ◽  
Piezoelectric Body ◽  
Quartz Disc ◽  
Piezoelectric Wafers

The torsional effect of a rectangular piezoelectric quartz is studied in the article. Using the anisotropic elasticity and Maxwell electromagnetic theory, the stress field and electrostatic field is founded, and then by the Finite Element Method the distribution of the electric field in the piezoelectric body is obtained. Based on theoretical analysis of the bound charge distribution, the measuring electrodes are effectively disposed on the surfaces of the piezoelectric wafers. The theoretical and experimental results show that the measurement charge is linear with the torque. The research will provide the basis for the torque measuring technique.

Collapse of Inverted Hemi-Ellipsoidal Shell Domes Under Uniform Pressure

1992 ◽  
Vol 36 (04) ◽  
pp. 378-386
Author(s):  
C. T. F. Ross ◽  
N. Rotherhamn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Analysis ◽  
Uniform Pressure ◽  
The Finite Element Method ◽  
Ellipsoidal Shell ◽  
Element Method

Nine hemi-ellipsoidal shell domes were tested to destruction, under uniform pressure acting on their concave surfaces. The shell domes varied from flat oblate hemi-ellipsoids to long prolate hemi-ellipsoids. The experimentally obtained collapse pressures showed that the flat oblate hemi-ellipsoidal domes and the long prolate hemi-ellipsoidal domes were stronger than the hemi-spherical and near hemi-spherical domes. The theoretical analysis was based on the finite-element method, and it showed that the theoretically obtained stresses were, in general, larger in magnitude than the experimentally obtained stresses.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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