Experimental Study on the Size Effect on Flexural Behavior of Larch Glulam Beams

2016 ◽  
Vol 847 ◽  
pp. 3-9 ◽  
Author(s):  
Xian Yan Zhou ◽  
Lei Cao ◽  
Dan Zeng
Keyword(s):  
Size Effect ◽  
Large Scale ◽  
Bending Strength ◽  
Weibull Model ◽  
Test Method ◽  
Flexural Behavior ◽  
Bending Test ◽  
Glulam Beam ◽  
Bending Modulus ◽  
Size Adjustment

At present, design values in codes and regulations are mainly based on test results of small size specimens, which are different from large-scale members used in practical engineering, therefore size adjustment coefficients are needed to be established. The four-point bending test method was adopted to investigate four groups of different sizes of Larch Glulam beams in their flexural behavior. Experiment data such as ultimate bearing capacity, deflection, strains and others are obtained, and the failure pattern and failure mechanism of bending members are analyzed. The research results indicate that the bending modulus of elasticity of Larch Glulam beam is not affected by the size. Bending strength of the Larch Glulam beam show a declining trend as the size of specimens increases, however, the ultimate bending moment increases. In addition, by means of a two-parameter Weibull model, a so-called size effect coefficient has been calculated by the slope method, thus providing a basis for the design and application of Larch Glulam beams.

scholarly journals Investigation of Interlaminar Defects and their Influence on Interlaminar Strength

1996 ◽  
Vol 5 (4) ◽  
pp. 096369359600500
Author(s):  
J Ziao ◽  
J Tao
Keyword(s):  
Tensile Strength ◽  
Large Scale ◽  
Peel Strength ◽  
Test Method ◽  
Bending Test ◽  
Four Point Bending ◽  
Transverse Tensile ◽  
Interlaminar Shear ◽  
Transverse Tensile Strength ◽  
Set Up

In this paper, we directed our attention to the interlaminar defects and their influence on the interlaminar strengths. With the aid of a S-570 scanning electron microscope, the morphology and distribution of interlaminar defects were inspected and documented. According to their shape, size and cause of formation, the defects were classified into five types: flakiness void, irregular shaped debond, local imperfectly cured resin, debond in two multi-directional plies, and inhomogeneous fibers and the large scale debond by these fibers. The cause of defects formation was discussed by analyzing the manufacturing process of composites. The influence of defects on the interlaminar strength and its mechanism was analyzed experimentally and theoretically. The results indicate that these defects, with different effects, decrease the interlaminar strength because they form interlaminar cracks, and the interlaminar shear strength is less affected than interlaminar tensile strength, which is measured according to GB4944 test method. To comprehend defects distribution effect, a four-point-bending test method was introduced to measure the interlaminar peel strength, and a discussion was made on the correlation between the interlaminar tensile strength, interlaminar peel strength and in-plane transverse tensile strength. Finally the concept of interlaminar defect coefficient, which can be used to characterize the defects, was set up and the formula to calculate it was proposed.

Bending Strength of Glulam from Selected Malaysian Hardwood Timber

2014 ◽  
Vol 879 ◽  
pp. 237-244 ◽  
Author(s):  
Wan Hazira Wan Mohamad ◽  
Zakiah Ahmad ◽  
Ashari Abd. Jalil
Keyword(s):  
Shear Test ◽  
Bending Strength ◽  
Glue Line ◽  
Bending Test ◽  
Timber Species ◽  
Bending Performance ◽  
Glulam Beam ◽  
Heavy Medium ◽  
Malaysian Government

Malaysian government has already built the first glulam structure in Malaysia with the aim of demonstrating the potentialities of using indigenous hardwood timber for glulam. Since Malaysia possesses a vast variety of timber species, hence there is a need to identify suitable species for glulam manufacturing. This paper presents the bending performance of Malaysian hardwood glulam beams, manufactured from different categories namely heavy, medium and light hardwood timbers. A series of tests were carried out on the glulam beam that includes bending test, delamination test and shear test of glue line. Results in this study will be useful to manufacturers interested in using Malaysian hardwood for glulam beams.

scholarly journals A Method for Assessing Axial and Temporal Effects of the Leaf Sheath on the Flexural Stiffness of the Maize Stem

2021 ◽  
Author(s):  
Jared Hale ◽  
Spencer Webb ◽  
Nathan Hale ◽  
Christopher Stubbs ◽  
Douglas D Cook
Keyword(s):  
Bending Strength ◽  
Statistical Significance ◽  
Temporal Patterns ◽  
Leaf Sheath ◽  
Test Method ◽  
Bending Test ◽  
Flexural Stiffness ◽  
Spatial And Temporal Patterns ◽  
Three Point Bending ◽  
Non Destructive

Abstract Background: The leaf sheath of many plants has been observed to influence both stiffness of the stem and ultimate strength. The leaf sheath has been implicated in studies of maize “greensnap” (or “brittle-snap”) failure. However, but the influence of the sheath is still not well understood and few methods exist for studying the influence of the sheath. The goal of this study was to develop a method for assessing longitudinal and temporal patterns of sheath influence on flexural stiffness. This metric of flexural stiffness was chosen because it is non-destructive and has been shown to be highly predictive of bending strength. Results: A three-point bending test method was successfully developed for assessing the influence of the sheath on flexural stiffness. The method relies upon comparisons between pairs of tests at the same location (sheath present vs. absent). The influence of the sheath was statistically significant in all varieties tested. The test method provided insights into the longitudinal and spatial variation of sheath influence: sheath influence appears to be closely related to maturity since both spatial and temporal patterns of influence mirror the sigmoidal maturation patterns previously observed in maize stalks. Conclusions: The paired nature of this test method increases statistical significance while the non-destructive feature of this test allows for multiple tests along the length of the stalk. This method can be used to provide new insightsregarding how the leaf sheath influences stalk flexibility (and therefore strength). Preliminary results indicate that the influence of the sheath changes over the life span of the plant in parallel with maturation patterns. However, further studies will be needed to confirm this hypothesis more broadly and to study additional issues such as heritability and the influce of genotype and environment on sheath influence.

scholarly journals Flexural Behavior of CFRP Laminate at Elevated Temperature

2017 ◽  
Vol 2 (3) ◽  
pp. 330-334
Author(s):  
Rzgar M. Abdalrahman
Keyword(s):  
Elevated Temperatures ◽  
Flexural Modulus ◽  
Peak Load ◽  
Test Method ◽  
Flexural Behavior ◽  
Bending Test ◽  
Effect Of Temperature ◽  
Flexural Properties ◽  
Flexural Behaviour ◽  
Cfrp Laminate

A carbon fibre reinforced polymer (CFRP) laminate forms the surface part of an integrally heated tool. It was made up of carbon non-crimp triaxial fibre and SR8100 epoxy in accordance to the stacking sequence of [(0, ±45)/ (90, ±45)] S, using the resin infusion (RI) method. The laminate is heated up to 90ºC when the tool is operated; therefore under-standing the effect of temperature on the flexural properties is quite significant. This experimental study is carried out to investigate the flexural behaviour of the CFRP laminate and finding its flexural properties under the effect of elevated temperatures. For this purpose, various CFRP specim-ens were prepared and tested, using three point bending test method, at different temperature levels from room temperature to 90ºC. The results show that each of the flexural peak load, modulus and strength of the laminate decreases consistently with the increase of temperature. Also the laminate becomes slightly more flexible and significant loss occurs in its flexural modulus when the temperature elevates from 75ºC to 90ºC. The reduction in the flexural behaviour of CFRP is imputed to thermal softening of the epoxy polymer matrix whenever becomes closer to (HDT).

scholarly journals KARAKTERISTIK SIFAT MEKANIK KOMPOSIT SERAT BAMBU RESIN POLYESTER TAK JENUH DENGAN FILLER PARTIKEL SEKAM

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Agus Budiman ◽  
Sugiman Sugiman
Keyword(s):  
Tensile Strength ◽  
Rice Husk ◽  
Bending Strength ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Bamboo Fiber ◽  
Bending Test ◽  
Bending Modulus ◽  
Bamboo Fibers ◽  
The Impact

This paper presents the effect of volume fraction of rice husks on the mechanical properties of bamboo fiber/unsaturated polyester composites. The composite specimens were made from bamboo fiber with fixed volume fraction of 40% and rice husk particle as filler with volume fractions varied 0%, 10%, 20% and 30%. Matrix used was unsaturated polyester resin. Bamboo fibers and rice husk were surface treated using alkali solution 4% (by weight) for 2 hours. The manufacturing process of composite was using hand layup method. The specimens were tested in tension, bending and in impact loading. The results show that the addition of rice husk particles up to volume fraction of 20% does not result in a decrease of tensile strength, but after a volume fraction of 20%, the tensile strength tends to decrease. In bending test, the rice husk volume fraction up to 20% increase the bending strength, but after that then it tends to decrease. However the bending modulus seems unaffected by the volume fraction of rice husk. Similar to the bending modulus, the impact strength is not significantly affected by the volume fraction of rice husk.

Increase of bending strength and maximum deflection of concrete reinforced with CFRP strips

2011 ◽  
Vol 18 (1-2) ◽  
pp. 93-97
Author(s):  
Goichi Ben ◽  
Kazuhiro Sakata ◽  
Kazuma Saito
Keyword(s):  
High Performance ◽  
Bending Strength ◽  
Concrete Beams ◽  
Beam Theory ◽  
Design Criterion ◽  
Test Method ◽  
Bending Test ◽  
Plastic Behavior ◽  
Four Point Bending ◽  
Miyagi Prefecture

AbstractIn 1981, many detached houses collapsed owing to the earthquake which took place at the coast of Miyagi Prefecture in Japan, because ferroconcrete was not used as the base of most of the collapsed houses. Therefore, the earthquake-proof design criterion was revised and it was obliged to use ferroconcrete as the base of detached houses ever since. However, there are still more than 10 million detached houses using aged concrete as the base in Japan. In this paper, a reinforcement method for the aged concrete is demonstrated by using the high performance carbon fiber reinforced plastic (CFRP) strips. Three kinds of concrete beams reinforced with the CFRP strips with different vertical insert positions and different numbers of the CFRP strips were tested by a four point bending test method. In order to clarify the effects of CFRP strips, a concrete beam without reinforcement was also tested. The results of the experiment showed that the maximum deflections of the concrete beams reinforced with the CFRP strip were more than 100 times larger than those of the concrete beams without reinforcement. Although the concrete beams without the CFRP strips collapsed instantly, the concrete beams reinforced with the CFRP strips gradually failed, which were similar to the plastic behavior of metals. This result means that the residents can afford to escape safely from the houses in the event of possible earthquakes. The experimental results were compared with the analytical ones obtained from the composite beam theory and the failure criterion. Both results showed good agreement and the effectiveness of base concrete reinforced with CFRP strips was demonstrated.

Bending Properties of Five-Layer Biaxial Weft Knitted Fabric Reinforced Composite Materials

2011 ◽  
Vol 391-392 ◽  
pp. 359-363 ◽  
Author(s):  
Wei Geng ◽  
Ye Xiong Qi ◽  
Jia Lu Li
Keyword(s):  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Volume Fraction ◽  
Test Method ◽  
Bending Test ◽  
Bending Properties ◽  
Fiber Volume ◽  
Reinforced Composite ◽  
Bending Load

Five-layer biaxial weft knitted (FBWK) fabric is one kind of multilayered biaxial weft knitted (MBWK) fabric. FBWK fabric is made of carbon fiber as inserted yarns and stitched with polyester yarns, and it has been impregnated with epoxy via resin transfer molding (RTM) technique to manufacture the composite plates. The bending properties of the FBWK fabric reinforced composite are studied with the three-point bending test method. The bending properties of the FBWK fabric reinforced composite materials with different fiber volume fraction have been investigated. The results show that the relationship between bending load and deflection is obviously linear before reaching the maximum load. Within a certain range, the bending strength of this kind of composites increases with the fiber volume fraction increasing. When the fiber volume fraction is 57%, the bending strength is 1051.4 MPa.

Experimental Characterization of Multiaxial Glass Laminates for Front End Cab

2015 ◽  
Vol 752-753 ◽  
pp. 291-294
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek ◽  
Vladimír Rusnák
Keyword(s):  
Large Scale ◽  
Fiber Composites ◽  
Flexural Behavior ◽  
Bending Test ◽  
Experimental Characterization ◽  
Three Point Bending ◽  
Glass Fiber Composites ◽  
Prepared Glass ◽  
Transport Industry

This research paper deals with an experimental investigation of mechanical properties of prepared composite panels. Flexural behavior in three-point bending test is measured. Composites are prepared in order to satisfy requirements for transport industry. Totally, three material compositions are tested with different multiaxial reinforcing fabric and polyester resin. All samples are produced by low-pressure vacuum infusion mainly used for large-scale composite parts. Furthermore, fire resistance of prepared laminates is tested and appropriate classification into corresponding categories is also done. Experimental results proved suitability of prepared glass fiber composites for application in transport industry.

Evaluation of Impact Bending Strength of Ceramic Composites at Ultra-High Temperatures from 1500-2000 °C in Air

2013 ◽  
Vol 591 ◽  
pp. 145-149 ◽  
Author(s):  
De Tian Wan ◽  
Yi Wang Bao ◽  
Hua Zhao ◽  
Yuan Tian
Keyword(s):  
High Temperatures ◽  
Bending Strength ◽  
Impact Load ◽  
Ceramic Composites ◽  
Test Method ◽  
Bending Test ◽  
Dynamic Force ◽  
Maximal Load ◽  
Impact Bending ◽  
The Impact

In this work, a new and novel test method was developed to determine the impact bending strength of ceramic composites at ultra-high temperature from 1500-2000 °C in air. Three-point impact bending test was carried out through a SiC pressure head with a dynamic force sensor fixed on a slider and movable along a guide rail. The impact load was adjusted by different saving energy and the impact speed was lower than 0.5 m/s. The center of the sample was heated up to about 1500-2000°C by oxygen-assisted spray combustion. An impact load was put on the specimen and the impact force was recorded automatically. The impact bending strength can be calculated from the maximal load and the sample size. To check the availability and reliability for this method, several ceramics including SiC, ZrB2/SiC and C/C fiber reinforced composite without coating, were used as the testing samples. The results indicate that this method is a good and feasible method for evaluating the mechanical properties of the ceramic composite at ultra-high temperatures.

Geometric Nonlinear Effect On Biaxial Bending Strength of Thin Silicon Die in the Ball-On-Ring Test

2021 ◽  
Author(s):  
Ming-Yi Tsai ◽  
H. Y. Liu
Keyword(s):  
Linear Theory ◽  
Large Deflection ◽  
Bending Strength ◽  
Test Method ◽  
Bending Test ◽  
Ring Test ◽  
Specimen Thickness ◽  
Biaxial Bending ◽  
Geometric Nonlinear ◽  
Thin Silicon

Abstract The ball-on-ring (BoR) test, one of the most popular biaxial bending tests, is thoroughly investigated in this study for determining the bending strength of thin silicon dies. The application of this test method with a linear theory to the thin dies is also reevaluated using a nonlinear finite element method (NFEM) by taking into account the geometric nonlinearities, including large-deflection (global) and contact (local) nonlinearities. Mechanics of the BoR test is also discussed in terms of geometric linearity and nonlinearity. It is found that the bending strength calculated by the existing linear theory for the BoR test is still valid for the non-thin die specimens, but not for thin ones. The reason is that the thin-die specimens in the test suffer a contact-nonlinearity effect, due to a maximum applied stress moving away from the loading pin center during the loading process. The global geometric nonlinear (large-deflection) behavior occurring in the three-point bending test is not observed in the test. For applications, the fitting equations of the maximum stress in terms of applied load are proposed based on the NFEM results. Those fitting equations only depend on the specimen thickness, the head radius of the loading pin, and the elastic modulus of the specimen, but not on the specimen radius, a supporting ring radius and the head radius of the ring. The 110 µm and 160 µm-thick silicon dies in the BoR test are also demonstrated with the related fitting equations.

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