2 edition of Effect of drying on damping and stiffness of nailed joints between wood and plywood found in the catalog.
Effect of drying on damping and stiffness of nailed joints between wood and plywood
Chu n Chou
Written in English
|Statement||by Chun Chou.|
|The Physical Object|
|Pagination||, 106 leaves, bound :|
|Number of Pages||106|
Polensek and Bastendorff-DAMPING IN NAILED JOINTS 11 1 ), compared to overall damping of 10°/o and more in nailed wood systems (Polensek , a). Damping in joints has been evaluated only for those between Douglas-fir lumber and sheathing such as plywood and gypsum wallboard (Yeh et al. 1 ; Atherton et al. ; Chou ). Rabe and Fonseca () investigated the effects of nail-drive depth on the strength of OSB joints. OSB joints constructed with 7/16 inch plywood sheathing attached to 2 by 4 wood members using 8d common or 8d cooler nails were tested using the sequential phased displacement (SPD) loading protocol.
atmosphere, i.e., when the air is humid, wood adsorbs moisture a nd swells; when the air is dry, wood loses moisture and shrinks. Various finishes and treatments may be used to slow this process, but, in general, they do not stop it. Likewise, air drying and kiln drying the wood do not prevent the wood from subsequent ly gaining or losing moisture. In a constrained layer damping system, sometimes referred to as CLD, a damping material is sandwiched between two other (usually stiff rigid) materials. For example, Green Glue sandwiched between two layers of drywall. Damping occurs when the viscoelastic center of the sandwich is sheared (see right).
Viscoelastic damping materials used between rigid panels such as drywall or plywood create a constrained layer damping (CLD) system. A specific, lab-tested VE damping material should be used, not construction adhesive or simple silicone caulk. with include; gypsum board (aka: sheetrock and drywall), plywood, metal, and various woods, typically. relationship between equilibrium moisture content, relative humidity, and temperature is generally independent of species and is shown in Table Table Moisture content of wood in equilibrium with stated dry-bulb temperature and relative humidity.
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Keywords: Damping, stiffness, slip, energy absorption, energy capacity, nailed joints, wood, plywood, testing, moisture content. INTRODUCTION Damping is the ability of a structure to dissipate energy during vibration.
The two sources of damping in nailed wood joints are material damping within theCited by: 9. Wood components, usually assembled in green or semi-dry condition, dry during the initial service life.
To evaluate the effect of such drying on joint stiffness and damping, cyclic-load tests were conducted on single-nail joints of wood and plywood that had been exposed to drying Cited by: 1.
Abstract. Graduation date: Wood components, usually assembled in green or semi-dry condition,\ud dry during the initial service life.
To evaluate the effect\ud of such drying on joint stiffness and damping, cyclic-load tests\ud were conducted on single-nail joints of wood and plywood that had\ud been exposed to drying cycles. Title: Effect of Drying on Damping and Stiffness of Nailed Joints between Wood and Plywood /.7 Abstract approved: Dr.
Anton Polensek Wood components, usually assembled in green or semi-dry condi-tion, dry during the initial service life. To evaluate the effect of such drying on joint stiffness and damping, cyclic-load tests were conducted on.
Among the different parameters that control seismic performance of wood-frame shear wall buildings damping has long been identified as an important contributor to.
Because testing conditions affect joint properties, nailed joints between wood and plywood and between wood and gypsum wallboard were tested to determine the effect. Single-nailed joints between 2X4-inch Douglas-fir lumber and plywood and between 2X4-inch Douglas-fir lumber and gypsum board were subjected to 4 fully-reversed cycles of tension/compression loading at 5 loads.
Load had a substantial effect on slip modulus and energy absorption (which is related to damping properties). The effects on slip modulus and energy. Chu n Chou has written: 'Effect of drying on damping and stiffness of nailed joints between wood and plywood' -- subject(s): Drying, Lumber, Damping (Mechanics) Asked in.
ABSTRACT. Dimensionally stable low-density (– g/cm 3) particleboard is required as a substitute for plywood paper discusses the limit for lowering the density of particleboards by using isocyanate resins and the effects of various factors such as the species (density) and configuration of the particles, the resin content and resin components on the.
Ordinarily, sufferers may also be vaccinated injections into a joint, each and every spaced injection per week. Some study suggests, analgesic effects, lubricate joints multiplied to 6 months or 1 yr through injection on cartilage cells and stimulating the phone membrane of the joints produced endogenous hyaluronic acid.
The present study deals with the stiffness and damping profiles of the leg joints during the ground-contact phase of hopping. A two-dimensional (sagittal plane) jumping model, consisting of four linked rigid segments and including the paired feet, shanks, thighs, and the head–arms–trunk segment, was developed.
And I understand damping as the energy dissipative properties of an object/system (e.g. a mass spring) under cyclic stress. In the context of a spring/oscillator, damping is what causes a spring to eventually stop oscillating. But I don't understand the real differences between the two.
Couldn't a spring's stiffness explain it's damping. Why not. The damping values in the tables should be used with caution.
There are many types of damping, such as viscous, hysteresis, acoustic coupling, air pumping at joints, energy radiation to the soil, etc. Also, boundaries and bearings contribute damping. Furthermore, structures have many modes. Each mode may have a unique damping value. References.
dimension after shrinkage has occurred as a result of the drying or “seasoning” process. Generally, there is a 1/4- to 3/4-inch difference between the nominal and dressed sizes of “dry” sawn lumber (refer to NDS-S Table 1B for specific dimensions).
For example, a 2x4 is actually inches by inches, a 2x10 is AMERICAN WOOD COUNCIL. 4 DETAILS FOR CONVENTIONAL WOOD FRAME CONSTRUCTION.
time of manufacture, producing mill number and the grad-ing rules writing agency. The bending strength, F. b, and the stiffness or modulus of elasticity, E, may be determined from the grade mark for lumber used as joists, rafters, and decking.
These values. Mass and stiffness are related together through the resonance frequency f0=(1/2pi)*sqrt(Stiffness/Mass). Damping effect is negligible/unimportant compared to both mass or stiffness, except when the SDOF is near from the resonance frequency.
Why. Because the mass effect is balanced/canceled by the stiffness effect. It is well established that one of the great obstacles to a complete understanding of the static and dynamic behaviour of machine tool structures is the inability to take the effects of the joints fully into account.
The relevant properties of the joints are the static stiffness and the damping. We have seen that stiffness, damping and now the destabilizing effects of shear are a cubed function of the film thickness. At smaller gaps where dynamic bearings operate, multiple rotordynamic properties are near asymptotic, with both heat generation and the destabilizing cross coupling changing dramatically with small changes in other properties.
THE EFFECT OF DRYING CONDITION ON POST FLOODING MECHANICAL PROPERTIES OF TIMBER SHEAR WALLS Alistair Bradley1, Wen-Shao Chang2, Richard Harris3 ABSTRACT: Due to anthropogenic global warming, flooding is an ever more likely occurrence, with more intense periods of heavy rain leading to a very real and immediate increase in flood risk.
The main conclusion of this paper is the important effect that joint stiffness and location with respect to mode shape, have on the damping. For example, a low stiffness joint can result in high or low loss factors depending on where on the panel the joint is located.
It is therefore necessary to study the joint location as the next variable to. At these boundaries, nailed wall-floor joints mainly resist the lateral forces occasionally in concert with other supplementary resisting elements.
The authors, in previous studies [1, 2], showed the effect of frictional resistance on the lateral resistance of the wall-floor joints of wooden light-frame constructions under static forces. In.The immediate,-reversible effect of high-temperature drying is important in the development of drying de-fects that result from breakage or crushing of wood cells.
When the drying stresses described in chapter 1 become greater than the strength of the wood, this type of drying defect develops.
This is why high tem-peratures early in drying are.not distinguish between the types of bolted joints. Table 2. Damping Values for Steel Buildings, Wind Excitation Joint Type Damping Ratio Welded Joints 2% Bolted Joints 5% Sandia Experimental Data, Beam Test Figure 1.
Jointed Beam A team of engineers led by Sandia National Laboratories performed some joint damping.