Download or read book Shear Strength of Structural Composite Lumber Using Torsion Tests written by R. Gupta and published by . This book was released on 2005 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Torsion tests were used to determine the shear strength of full-size structural composite lumber (SCL). Eighty-five rectangular specimens of laminated strand lumber (LSL), laminated veneer lumber (LVL), and parallel strand lumber (PSL) were tested. LSL failed along the strand (LT Plane) and in a brittle manner. LVL and PSL failed across the veneer/strand (LR plane) and in a ductile manner. Different failure modes were observed due to the differences in the shear moduli in two longitudinal planes (GLT and GLR). Based on orthotropic theory, the shear strength of LSL, LVL, and PSL is 6.43 MPa (TLR), 7.96 MPa (TLT), and 6.82 MPa (TLT), respectively. Based on the results of this study, the torsion test is recommended as a standard method for determining the pure shear strength of full-size SCL, since it is the only known test method to date that imposes a state of pure shear stress in the specimens.
Download or read book Evaluation of the Torsion Test as a Method to Determine the Shear Strength of Structural Composite Lumber written by Tobias Stefan Siller and published by . This book was released on 2002 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Torsional Shear Strength and Size Effect in Structural Composite Lumber written by Zhuo Yang and published by . This book was released on 2012 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: The natural variation of strength properties within brittle materials leads to size effect, a well-known phenomenon whereby the mean strength of a material is observed to decrease as the stressed volume increases. An important implication of size effect is that size adjustment parameters must be incorporated into multi-axial constitutive and failure models used in numerical simulations to predict material response to loading. This experimental study seeks to verify and quantify the presence of depth effect under shear failure in the orthotropic principal material directions of parallel strand lumber (PSL) and laminated veneer lumber (LVL). Torsion tests have been performed on specimens of fixed length and differing cross section to get a pure shear failure, by using a Universal Test Machine. The experimental results indicate that there is no depth effect for LVL from torsional shear stresses. PSL testing was limited to one size, and depth effect was not evaluated. A finite element model was built to simulate the torsional test for the 44x140mm LVL specimen. Comparing the experimental test results and the simulation results, the model provided an accurate prediction of the torsional test for Structural Composite Lumber.
Download or read book Evaluation of the Torsion Test for Determining the Shear Strength of Structural Lumber written by Leanne Renee Heck and published by . This book was released on 1997 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: The torsion test was evaluated as a method for determining the shear strength of full-size structural lumber. The evaluation involved an experimental length study, an experimental depth study, and a finite element study. The length study consisted of fifty nominal 2x4 specimens, ten specimens for each length, and ten American Society for Testing and Materials (ASTM) shear blocks. One 14 foot long board yielded one specimen for each length: (a) 21.0", (b) 28.5", (c) 32.0", (d) 35.5", (e) 39.0", and (f) an ASTM D143-94 shear block. The statistical analysis revealed no evidence that the length affected the shear strength. The depth study consisted of fifty specimens, ten specimens for each depth: (a) 2x4, (b) 2x6, (c) 2x8, (d) 2x10, and (e) 2x12. In addition, fifty ASTM shear blocks, one block for each specimen, were tested. The statistical study did not reveal convincing evidence of a depth effect on shear strength, even after accounting for specific gravity and shear span as covariates. Failure modes for the torsion samples involved a longitudinal shear crack at the mid-point of the longest side, which propagated toward the ends of the specimen and through the cross section perpendicular to the growth rings. The finite element model revealed that uniform shear stress occurs within the shear span, which begins and ends a distance of approximately two times the depth plus the grip distance away from each end of the member. In addition, torsion theory verified that the experimental shear failure plane that occurs within the shear span is parallel to the grain and the shear slippage is also parallel to the grain, similar to the known shear failure in specimens subjected to bending loads. Based on the results of this study, the torsion test is the best practical method to determine the pure shear strength of full-size structural lumber, because the test yields 100% shear failures and the specimen is in a state of pure shear stress.
Download or read book Comparative Test Methods for Evaluating Shear Strength of Structural Lumber written by Djoko S. Riyanto and published by . This book was released on 1996 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Five different test methods to determine the parallel-to-grain shear strength of Douglas-fir structural lumber were compared. Four methods assessed the shear strength of lumber sections having a full nominal two by four inch cross-section. These were: three-point bending, four-point bending, five-point bending, and torsion. The fifth method was the ASTM D 143 small specimen test for the shear strength of clear wood. A completely randomized statistical design used seventy six pieces of nominal 2x4 inch, 12 feet long lumber to make 380 matched specimens for the five test methods (76 specimens for each test method). All full cross-section bending specimens had a constant shear span of 5d, where d is the depth of the specimen (3.5 inches). The small, clear specimens were similar to those specified in ASTM D 143 except that the thickness was one and a half inches. Analysis of variance indicated that at least one of the average shear strengths from the five different test methods was significantly different from the other (p-value = 0.00) at 5% significance level. The Duncan multiple comparison test showed that the average shear strength from the three-point bending test and the torsion test are not statistically different. The torsion test appeared to be the best test method for determining shear strength of wood as a material because this test is able to produce pure shear stress in the specimen, and always produces shear failure. The three-point bending test was a good test method for determining shear strength of wood as a structural component because this test uses a bending s et-up which closely approximates real life applications of wood, and produces the highest percentage of shear failure among the other bending test methods. The shear strengths determined from the torsion test, three-point bending test, and five-point bending test are linearly correlated with the shear strength obtained from the small, clear specimen test. The shear strengths from the small, clear specimen test and the torsion test have significant relationships with specific gravity. No test shear strength had a significant relationship with bending modulus of elasticity of original lumber.
Download or read book Experimental Evaluation of the Torsion Test for Determining Shear Strength of Structural Lumber written by R. Gupta and published by . This book was released on 2002 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The torsion test was evaluated as a method for determining shear strength of full-size, structural lumber by length and depth studies. The length study consisted of fifty 38 by 89 mm specimens, ten each of lengths 0.5 m, 0.7 m, 0.8 m, 0.9 m, and 1.0 m, and ten shear blocks. The statistical analysis showed no evidence that length affected shear strength. The depth study consisted of 50 specimens, ten each of sizes 38 by 89 mm, 38 by 140 mm, 38 by 184 mm, 38 by 235 mm, and 38 by 286 mm, and 50 shear blocks. The statistical analysis did not show convincing evidence of a depth effect on shear strength, even after accounting for specific gravity and shear span as covariates. Failure modes were similar to shear failures observed in bending tests, and involved a longitudinal shear crack at the wide face, which propagated toward the ends of the specimens and through the cross section perpendicular to growth rings. Based on results of this study, the torsion test is the best practical method for determining pure shear strength of full-size, structural lumber.
Download or read book Mechanical Properties of Laminated Veneer Lumber Via Five Point Bending Test written by JP. Bradtmueller and published by . This book was released on 1998 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The five-point bending test is shown to be an effective and efficient way of determining the mechanical properties of structural composite lumber. Shear strength, bending strength, shear-free Young's modulus of elasticity and shear modulus for both plank (flatwise) and joist (edgewise) orientations can be obtained with simple adjustments of the test configuration. Span or span-to-depth ratios are adjusted to produce either predominantly shear or bending failure. To determine elastic constants, a removable center support creates the necessary situation for both four-point bending and five-point bending. Use of a deflection yoke is especially important in determining the shear moduli. Results are reported for testing laminated veneer lumber. which was selected as representative of the evolving family of structural composite lumber products.
Download or read book Pilot Study of Shear Strength of Structural Composite Lumber I Configuration written by Winnie Yick Man Louis and published by . This book was released on 1997 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Transverse Shear Strength Through Torsion Testing written by KT. Marcucelli and published by . This book was released on 1997 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The in-plane characterization of composite materials is, in general, well understood and widely utilized throughout the aerospace industry. However, the use of composites in structural elements such as fuselage frames and rotorcraft flexbeams place large out-of-plane or through-the-thickness stresses for which there is little data. Efforts to determine the interlaminar shear strength of laminated composites have been hampered due to the nonlinear behavior of test specimens and the limitations of current analysis tools.
Download or read book Engineered Bamboo Structures written by Yan Xiao and published by CRC Press. This book was released on 2022-04-29 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bamboo is in the spotlight as a potential building material in the current pursuit of a CO2-neutral society, due to its rapid maturation and excellent mechanical properties. Despite the growing interest in bamboo in academia and society, there is a lack of systematic understanding of the fabrication, design and construction processes using bamboo as a modern industrial material. This is the first book to describe a new category of structural systems constructed with engineered bamboo. It gives a definition of engineered bamboo (glubam) in an analogy with steel structures and wood structures. Structural systems and components have been designed using glubam; then industrialized production processes of glubam are described. Based on state-of-the-art research, design guidelines are suggested, in a comparable and parallel approach to the existing guidelines for composite wood structures. The book also discusses bamboo structures in the context of sustainable development, including the benefits of using bamboo as an alternative or replacement for wood, especially for developing countries, many of which are faced with the lack or destruction of forest resources.
Download or read book Experimental Shear Strength of Unchecked Solid sawn Douglas fir written by Douglas R. Rammer and published by . This book was released on 1996 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evolution of Allowable Stresses in Shear for Lumber written by and published by . This book was released on 1979 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural Design and Analysis written by C. C. Chamis and published by Elsevier. This book was released on 2016-06-03 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: Composite Materials, Volume 8: Structural Design and Analysis, Part II covers the methods of structural design and analysis. The book discusses the discrete element analysis of composite structures; the concepts of probabilistic design and reliability as it pertains to composites; and the experimental methods for characterizing composites and composite components. The text also describes the state-of-the-art of the analysis of discontinuities, edge effects, and joints in composites; as well as the methodology for designing composite structural components. Materials scientists, materials engineers, and researchers of fiber composites will find the book invaluable.
Download or read book Length Effects in Tensile Strength in the Orthogonal Directions of Structural Composite Lumber written by Sanjay R. Arwade and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The natural variation of strength properties within brittle materials leads to the phenomenon of size effect which causes the expected strength of a material to decrease as the stressed volume increases. An important implication of size effect is that size adjustment parameters must be incorporated into multi-axial constitutive and failure models used in numerical simulations such as those made using the finite element method. These size adjustments are based on the sizes of the individual elements, rather than the size of the structural member. This experimental study seeks to determine whether such a size effect is present in the orthotropic principal material directions of parallel strand lumber (PSL) and laminated veneer lumber (LVL), and, if the effect is present, to quantify it. Tensile tests were performed on specimens of different test section lengths oriented in the longitudinal, transverse, and through-thickness (PSL only) directions and size effect adjustment parameters were estimated. Statistical results indicate the existence of size effect in LVL and PSL for the longitudinal and transverse directions.
Download or read book Advanced Fibre Reinforced Polymer FRP Composites for Structural Applications written by Jiping Bai and published by Woodhead Publishing. This book was released on 2022-12-05 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced Fibre-reinforced Polymer (FRP) Composites for Structural Applications, Second Edition provides updates on new research that has been carried out on the use of FRP composites for structural applications. These include the further development of advanced FRP composites materials that achieve lighter and stronger FRP composites, how to enhance FRP integrated behavior through matrix modification, along with information on pretension treatments and intelligence technology. The development of new technology such as automated manufacturing and processing of fiber-reinforced polymer (FRP) composites have played a significant role in optimizing fabrication processing and matrix formation. In this new edition, all chapters have been brought fully up-to-date to take on the key aspects mentioned above. The book's chapters cover all areas relevant to advanced FRP composites, from the material itself, its manufacturing, properties, testing and applications in structural and civil engineering. Applications span from civil engineering, to buildings and the energy industry. Covers all areas relevant to advanced FRP composites, from the material itself, its manufacturing, properties, testing and applications in structural engineering Features new manufacturing techniques, such as automated fiber placement and 3D printing of composites Includes various applications, such as prestressed-FRP, FRP made of short fibers, continuous structural health monitoring using advanced optical fiber Bragg grating (FBG), durability of FRP-strengthened structures, and the application of carbon nano-tubes or platelets for enhancing durability of FRP-bonded structures
Download or read book Symposium on Shear and Torsion Testing written by and published by ASTM International. This book was released on 1961 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt:
