Author: C. C. GerhardsPublisher:
ISBN:
Category : Loading and unloading
Languages : en
Pages : 30
Book Description
Effect of Duration and Rate of Loading on Strength of Wood and Wood-based Materials
Author: C. C. GerhardsPublisher:
ISBN:
Category : Loading and unloading
Languages : en
Pages : 30
Book Description
Effect and Duration and Rate of Loading on Strength of Wood and Wood-based Materials
Author: Charles C. GerhardsPublisher:
ISBN:
Category :
Languages : en
Pages : 24
Book Description
This study reviews world literature on the strength-related effect of duration and rate of loading on wood and wood-based materials. Also, early developments are discussed which led to the currently used permament loading factor of 9/16. Published data on duration of load are reanalyzed and compared. The comparisons suggest that the effect of stress level on duration of stress for wood is greater for shear than for bending or compression. The comparisons also suggest that the stress level effect is greater in hardboard, particle board, and plywood than in solid wood. A similar comparison of loading rate effects suggests that strength is affected to a greater extent in green wood than in dry wood, particularly in bending. For dry wood, the effect of loading rate on strength is most pronounced in tension perpendicular to grain, followed by compression parallel to grain, bending, and shear. Results also suggest that loading rate in bending has a slightly greater effect on hardboard strength and a slightly lesser effect on particle board strength compared to strength of wood. The shortcomings of the present data on loading rate and duration are discussed. Suggestions are made for needed research. (Author).
Effect of Duration and Rate of Loading on Strength of Wood and Wood-based Materials
Author: C. C. GerhardsPublisher:
ISBN:
Category : Loading and unloading
Languages : en
Pages : 28
Book Description
The Influence of Rate of Loading on the Strength of Wood and Wood-Base Materials
Author: J. A. LiskaPublisher:
ISBN:
Category : Nonmetallic materials
Languages : en
Pages : 16
Book Description
That the strength properties of wood and wood-base materials are influenced by duration of stress has long been recognized, both in the use of design stresses and through the establishment of rate of loading requirements in standard test methods. This paper presents a summary of recent data that supplements the information presented by the authors at the 1948 ASTM symposium on the same subject (4). Extensive data have been obtained on the effect of rate of loading on the compression-parallel-to-grain and flexural strength properties of two hardwood and two softwood species. The similarity of trends obtained from short-time and long-time tests indicates that the relationship between ultimate strength and time can be presented in a simple curve from load durations of a fraction of a second to many years. Values for modulus of elasticity remain substantially constant irrespective of rate of loading. Data are also presented to show that the flexural strength of building fiberboards of the densities tested is increased as the rate of loading is increased. Further tests are necessary, however, to establish more precisely the magnitude of this effect for fiberboards. Additional studies are needed further to determine, for both wood and wood-base materials, the influence of rate of loading on other mechanical properties, and to provide more substantial data on the effect of loadings extended over many years.
Relation of Strength of Wood to Duration of Load
Author: Lyman W. WoodPublisher:
ISBN:
Category : Loads (Mechanics)
Languages : en
Pages : 12
Book Description
Bowing in Roof Joists Induced by Moisture Gradients and Slope of Grain
Author: Roger L. TuomiPublisher:
ISBN:
Category : Roofing
Languages : en
Pages : 556
Book Description
Scientific and Technical Aerospace Reports
Author: The Mechanical Properties of Wood, Including a Discussion of the Factors Affecting the Mechanical Properties, and Methods of Timber Testing
Author: Samuel James RecordPublisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 200
Book Description
Handbook of Wood Chemistry and Wood Composites
Author: Roger M. RowellPublisher: CRC Press
ISBN: 0203492439
Category : Science
Languages : en
Pages : 505
Book Description
The degradable nature of high-performance, wood-based materials is an attractive advantage when considering environmental factors such as sustainability, recycling, and energy/resource conservation. The Handbook of Wood Chemistry and Wood Composites provides an excellent guide to the latest concepts and technologies in wood chemistry and bio-based composites. The book analyzes the chemical composition and physical properties of wood cellulose and its response to natural processes of degradation. It describes safe and effective chemical modifications to strengthen wood against biological, chemical, and mechanical degradation without using toxic, leachable, or corrosive chemicals. Expert researchers provide insightful analyses of the types of chemical modifications applied to polymer cell walls in wood, emphasizing the mechanisms of reaction involved and resulting changes in performance properties. These include modifications that increase water repellency, fire retardancy, and resistance to ultraviolet light, heat, moisture, mold, and other biological organisms. The text also explores modifications that increase mechanical strength, such as lumen fill, monomer polymer penetration, and plasticization. The Handbook of Wood Chemistry and Wood Composites concludes with the latest applications, such as adhesives, geotextiles, and sorbents, and future trends in the use of wood-based composites in terms of sustainable agriculture, biodegradability and recycling, and economics. Incorporating over 30 years of teaching experience, the esteemed editor of this handbook is well-attuned to educational demands as well as industry standards and research trends.
Author: