Stress wave techniques for determining quality of dimensional lumber from switch ties

Cover of: Stress wave techniques for determining quality of dimensional lumber from switch ties |

Published by U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory in Madison, WI .

Written in English

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Subjects:

  • Red oak -- United States -- Quality,
  • Lumber -- Drying -- Grading -- United States,
  • Stress waves,
  • Nondestructive testing

Edition Notes

Book details

StatementKristin C. Schad ... [et al.]
SeriesResearch note FPL -- RN-0265, Research note FPL -- 0265
ContributionsSchad, Kristin C, Forest Products Laboratory (U.S.)
The Physical Object
FormatMicroform
Pagination12 p.
Number of Pages12
ID Numbers
Open LibraryOL14458759M
OCLC/WorldCa34134844

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Stress wave techniques for determining quality of dimensional lumber from switch ties. Res. Note FPL–RN– Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory.

12 p. A limited number of free copies of this publication are. Get this from a library. Stress wave techniques for determining quality of dimensional lumber from switch ties. [Kristin C Schad; Forest Products Laboratory (U.S.);]. A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text.

Longitudinal stress wave and transverse vibration nondestructive evaluation techniques have proven to be accurate means of evaluating the quality of wood-based products.

Researchers have found strong relationships between stress wave and transverse vibration parameters (e.g., wave velocity and predicted modulus of elasticity) with the actual Author: Udaya B. Halabe, Gangadhar M. Bidigalu, Hota V.

GangaRao, Robert J. Ross. the application of stress wave techniques. Current stress wave methods for wood property evaluation are limited to wood members with a simple boundary condition, where one end of the material (in longitudinal direction) is usually accessible.

Therefore, these methods are not adaptable to trees. In this study, we used a newly developed approach to. The study was aimed at analyzing the R&R of using Metriguard A Stress Wave Timer to measure the MOE of the structural dimension lumber of lodgepole pine (Pinus contorta var.

latifolia), and providing a scientific measurement, i.e. a measurement plus an uncertainty, for any accredited testing laboratory and quality control department in a Cited by: 3. David W. Green's research while affiliated with Forest Laboratories, Inc. and Stress Wave Techniques for Determining Quality of Dimensional Lumber From Switch Ties Quality of Dimensional.

System for and method of performing evaluation techniques on a log or round timber Xiping Wang Robert J. Ross Stress wave techniques for determining quality of dimensional lumber from switch ties Cited by:   A stress-wave technique for determining the dynamic tensile strength of brittle materials is discussed.

The results of experiments with bar specimens of aluminum oxide are presented. Experimental evidence to verify the reliability of the state of dynamic tensile stress resulting from the reflection of a longitudinal stress wave from a free boundary is by: 8.

Longitudinal stress waves for lumber stress grading: Factors affecting applications: state of the art [Gerhards, C. C] on *FREE* shipping on qualifying offers. Longitudinal stress waves for lumber stress grading: Factors affecting applications: state of the artAuthor: C.

C Gerhards. 3-layer laminated veneer lumber with clear, straight-grained outer layers and an inner layer with sloping grain and a crack parallel to that grain. This analysis provides a theoretical means of determining the tension behavior of the material containing a crack at any angle to the direction of the stress andCited by: Allowable Stress Design of Simple Shear Paperback – January 1, by Aisc (Author) out of 5 stars 1 rating5/5(1).

The testing experiments to healthy larch logs samplings whose diameter scopes are in cm and the length respectively are 10cm and 30cm were conducted by using Arbotom stress wave testing instrument and universal mechanics testing machine. The relationships between dynamic modulus of elasticity of stress wave and MOE, between MOR and MOE were all studied in the larch logs : Ju Ying Luo, Xue Chun Yang.

where a and b are the incident and refracting angles; C //, C r, are the sound velocity in wood parallel and perpendicular to grain and C Al is the sound velocity in aluminum.

Since damping is very high perpendicular to the grain, these waves degenerate quickly, b soon approaches 90°, and the waves will propagate in the grain direction.

As the speed of sound is highly variable in wood, it is. Stress wave and static bending tests were then performed on these specimens to determine strength and stiffness. Results of this study indicate that in situ stress wave measurements could provide relatively accurate and reliable information that would enable nondestructive evaluation of Cited by: 1.

Capable of significant shape change when hot working is used. Positive effect on part strength when cold working is used. Most processes include little material waste and they are net shape processes.

The split Hopkinson bar (SHB) technique, first introduced by Kolsky, is one of the most widely used methods to study material behaviors under high nominal strain rate in a range of 10 2 –10 4 s − general, SHB methods are classified into torsion (SHToB), compression (SHPB) and tension (SHTB),, split Hopkinson bars.

Recently, tensile SHTB test are widely used to measure the Cited by: 7. The modulus of elasticity (MOE) is a mechanical property of wood that can be measured rapidly and nondestructively.

Research to establish relationships between MOE and modulus of rupture of commercial lumber has been conducted for five principal species of Cited by: 5. Determining Lengths of Installed Timber Piles by Dispersive Wave Propagation J. DARRIN HOLT, SHUNYI CHEN, AND ROBERT A. DOUGLAS Timber piles are used as a primary means of support for many struc­ tures, such as bridges, throughout the continental.

To compare stress distribution in a tooth restored with metal and fiber posts of varying diameters ( and mm) by means of three-dimensional finite element analysis (3D-FEA).Four 3D-FEA models were constructed: (1) fiber post ( and mm) and.

- Visually graded lumber is divided into categories based on nominal size. - Same grade of lumber in a species can have different allowable stresses based on what category it's' in - Boards: 1" - " thick and 2"+ wide - Dimensional Lumber: 2" - 4" thick and 2"+ wide - Timbers: 5" thick and 5"+ wide.

Full-size structural lumber under torsion was analyzed using the finite-element method to determine stress distribution. A three-dimensional, homogeneous, orthotropic finite-element model was developed and analyzed using commercially available software, ANSYS®, to increase understanding of stress distribution and failure by: Determining Maximum Bending Stress For a prismatic member (constant cross section), the maximum normal stress will occur at the maximum moment.

For a non-prismatic member, the stress varies with the cross section AND the moment. C D (dead load). dead load 0 9 File Size: 2MB. tact. Thus, a stress-laminated lumber deck is slightly less efficient than a continuous glulam deck of the same size.

Based on research work conducted by MTO and Queen’s University, 5,6,7 as well as successful rehabilitation projects in Ontario, a design procedure for stress-laminated decks was developed and included in the editionFile Size: KB. Three-dimensional finite element analysis of stress distribution in a tooth restored with metal and fiber posts of varying diameters: An in-vitro study.

Kumar P(1), Rao RN(2). Author information: (1)Department of Conservative Dentistry and Endodontics, Yenepoya Dental College, Mangalore, Karnataka, by: 3. The stress concentration factors (S.C.F) for various holes and edge notches in structural members have been evaluated numerically based on the written BEM program and experimentally based on laboratory testing of representative specimens coupled with strain gauge techniques.

Contact stress from hertz equation is σ c = MPa. Shear Stress using Lewis Bend Strength Equation The effect of the fillet, at the tooth pair, on the stress concentration is ignored. For the cantilever formed tooth, the maximum stress [8, 9] is found at the tooth root. The application of the standard bending stress equation (S=M/Z Cited by: 1.

shear stress. A review of the available gauges is given by Winter ~!. If the value of the wall shear stress is low, as expected in blood flow @maximum values: 2–3 Pa, Giddens et al. ~!#, an accurate measurement of the stress is only possible if the surface of the sensing element is relatively large, thus, limiting the applicability File Size: KB.

Shearing stress distribution in typical cross-sections: Let us consider few examples to determaine the sheer stress distribution in a given X- sections Rectangular x-section: Consider a rectangular x-section of dimension b and d A is the area of the x-section cut off by a line parallel to the neutral axis.

is the distance of the centroid of A fromFile Size: KB. Consequently, the objective of the research was to change the values of tensile stress without changing the values of bending stress, nominal plywood thickness or total number of layers.

The research results show that by changing the thickness of only three layers located closest to the middle surface of the panel, full optimization of tensile Cited by: 3. Determination of elastic T-stress x, and x2 directions. (Here E is Young’s modulus.)Under two-dimensional plane strain conditions .sjj = O), we have G* = 0.

For the purpose of extracting the T-stress distribution along the crack front of a. (B) Flexural Stress Waves The problem of flexural stress wave propagation in beams has not been so extensively treated as has the problem of axial wave propagation.

This is due to the complexities involved in the propagation of such waves and their dispersive character (Al-Mousawi, et al., ). corresponding stress amplitude that will produce the same ΔG for an R-ratio ofthe results illustrated in.

Figure 1 are obtained. Using ΔG = G. max – G. min, the resultant stress amplitude and mean stress are influenced by R-ratio, while for Δ.

G = (√ G. max – √ G. File Size: KB. sizes of dimension lumber presented an immense problem. Consequently, the authors concluded that beams having smaller cross sections should not be tested in the five-point configuration or that a standard test method, which is ap-plicable to all sizes of lumber, should be introduced.

One such method, as shown by Gupta et al. (a), is a Cited by: BEAMS: SHEARING STRESS ( – ) Slide No. 4 Shearing Stress in Beams ENES ©Assakkaf Shear and Bending – The presence of a shear force indicates a variable bending moment in the beam.

– The relationship between the shear force and the change in bending moment is given by dx dM V = (42) LECTURE BEAMS: SHEARING STRESS ( – 6 File Size: KB. Tests were carried out on shear walls with diagonal or transverse (horizontal) lumber sheathing.

A total of 16 full-scale shear walls were tested to investigate the effects of hold-downs, vertical load, and width of lumber sheathing on in-plane shear capacity.

tensile and compressive stress strain curves of a cast Iron material [5]. A few years later, similar experimental techniques were performed by Nadai [6] and Marin [3].

ByLaws [7] published a research on a method by which he calculated stress-strain curves through the data of a bending test for a composite material. Results wereFile Size: KB. Civil Engineering Assignment Help, Stress-strain curves represents a soft and weak material, Which of the following stress-strain curves represents a soft and weak material.

Solution: As depicted, stress is on the y-axis while the x-axis represents "a" is compared to "b", the stress is less. Comparatively, both c a. These are often called horizontal shear stresses. In plywood, this type of stress is called rolling shear stress.

Shear stresses should be checked carefully in lumber beams and plywood. For short, heavily loaded spans, shear stress frequently controls the lumber beam or plywood capacity.

allowable shear stress for the wood is allow 3 MPa. What is the required spacing s of the nails used to hold the top and bottom flanges to the web if each nail can resist a shear force of N.

As shown on FBD Vmax P, VAC VDB P, VCD 0 y yA A 0 75 10 1 5 7 5 12 1 14 25 6 1 5 10 1 5 12 1 6 1 5 6 ().). ()(). ().) .) .) m. c I 1 12File Size: KB. -DIMENSIONAL ANALYSIS OF MICROSCOPIC STRESS DISTRIBUTON AT A FREE EDGE OF A CROSS-PLY CFRP LAMINATE and macroscopic strain E ij of the laminate are derived in the same forms as in the conventio nal homogenization theory: [2] (), kl V G G F ij ijpq pk ql p q kl cE, (7).

(), kl 6 G G F.Wood Design Notation: a = name for width dimension A = name for area Areq’d-adj = area required at allowable stress when shear is adjusted to include self weight b = width of a rectangle = name for height dimension c 1 = coefficient for shear stress for a rectangular bar in torsion C C = curvature factor for laminated arches C DFile Size: 1MB.Bending strength and stress wave grading of (tropical) hardwoods determining parameter.

On the basis of the test series, azobé has been assigned to strength The dynamic modulus of elasticity was determined using stress wave analysis equipment developed at .

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