Flexural Behavior of Six Species of Italian Bamboo

2022 ◽  
Author(s):  
Silvia Greco ◽  
Luisa Molari
Keyword(s):  
Structural Material ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Functionally Graded ◽  
Flexural Behavior ◽  
Bending Test ◽  
Bamboo Species ◽  
Four Point Bending ◽  
Flexural Ductility ◽  
Graded Material

The good mechanical performance of bamboo, coupled with its sustainability, has boosted the idea to use it as a structural material. In some areas of the world it is regularly used in constructions but there are still countries in which there is a lack of knowledge of the mechanical properties of the locally-grown bamboo, which limits the spread of this material. Bamboo is optimized to resist to flexural actions with its peculiar micro structure along the thickness in which the amount of fibers intensifies towards the outer layer and the inner part is composed mostly of parenchyma. The flexural strength depends on the amount of fibers, whereas the flexural ductility is correlated to the parenchyma content. This study focuses on the flexural strength and ductility of six different species of untreated bamboo grown in Italy. A four-point bending test was carried out on bamboo strips in two different loading configurations relating to its microstructure. Deformation data are acquired from two strain gauges in the upper and lower part of the bamboo beam. Difference in shape and size of Italian bamboo species compared to the ones traditionally used results in added complexity when performing the tests. Such difficulties and the found solutions are also described in this work. The main goal is to reveal the flexural behavior of Italian bamboo as a functionally graded material and to expand the knowledge of European bamboo species toward its use as a structural material not only as culm but also as laminated material.

Flexural behavior of functionally graded polymeric composite beams

2021 ◽  
pp. 152808372110003
Author(s):  
M Atta ◽  
A Abu-Sinna ◽  
S Mousa ◽  
HEM Sallam ◽  
AA Abd-Elhady
Keyword(s):  
Flexural Strength ◽  
Volume Fraction ◽  
Stress Gradient ◽  
Polymeric Composite ◽  
Composite Beams ◽  
Functionally Graded ◽  
Flexural Behavior ◽  
Bending Test ◽  
Polymeric Composite Material ◽  
Fiber Volume

The bending test is one of the most important tests that demonstrates the advantages of functional gradient (FGM) materials, thanks to the stress gradient across the specimen depth. In this research, the flexural response of functionally graded polymeric composite material (FGM) is investigated both experimentally and numerically. Fabricated by a hand lay-up manufacturing technique, the unidirectional glass fiber reinforced epoxy composite composed of ten layers is used in the present investigation. A 3-D finite element simulation is used to predict the flexural strength based on Hashin’s failure criterion. To produce ten layers of FGM beams with different patterns, the fiber volume fraction ( Vf%) ranges from 10% to 50%. A comparison between FGM beams and conventional composite beams having the same average Vf% is made. The experimental results show that the failure of the FGM beams under three points bending loading (3PB) test is initiated from the tensioned layers, and spread to the upper layer. The spreading is followed by delamination accompanied by shear failures. Finally, the FGM beams fail due to crushing in the compression zone. Furthermore, the delamination failure between the layers has a major effect on the rapidity of the final failure of the FGM beams. The present numerical results show that the gradient pattern of FGM beams is a critical parameter for improving their flexural behavior. Otherwise, Vf% of the outer layers of the FGM beams, i.e. Vf% = 30, 40, or 50%, is responsible for improving their flexural strength.

scholarly journals Flexural behavior of sandwich panels with cellular wood, plywood stiffener/foam and thermoplastic composite core

2017 ◽  
Vol 21 (2) ◽  
pp. 784-805 ◽  
Author(s):  
Edgars Labans ◽  
Kaspars Kalnins ◽  
Chiara Bisagni
Keyword(s):  
Mechanical Performance ◽  
Sandwich Panels ◽  
Experimental Tests ◽  
Design Tool ◽  
Thermoplastic Composite ◽  
Flexural Behavior ◽  
Four Point Bending ◽  
Reliable Design ◽  
Sufficient Strength ◽  
Core Part

A series of experimental tests have been carried out on three types of novel sandwich panels mainly designed for application in lightweight mobile housing. Two types of the panels are manufactured entirely from wood-based materials while the third one presents a combination of plywood for surfaces and corrugated thermoplastic composite as a core part. All sandwich panels are designed to allow rapid one-shot manufacturing. Mechanical performance has been evaluated in four-point bending comparing the data to the reference plywood board. Additionally, finite element simulations were performed to evaluate global behavior, stress distribution and provide the basis for a reliable design tool. Obtained results show sufficient mechanical characteristics suitable for floor and wall units. Compared to a solid plywood board, sandwich alternative can reach up to 42% higher specific stiffness, at the same time maintaining sufficient strength characteristics.

scholarly journals An Efficient Approach to Describe the Fiber Effect on Mechanical Performance of Pultruded GFRP Profiles

2021 ◽  
Vol 8 ◽  
Author(s):  
Viktor Gribniak ◽  
Arvydas Rimkus ◽  
Linas Plioplys ◽  
Ieva Misiūnaitė ◽  
Mantas Garnevičius ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Mechanical Load ◽  
Computation Time ◽  
Image Correlation ◽  
Flexural Behavior ◽  
Bending Test ◽  
Experimental Program ◽  
Fe Model ◽  
Hollow Section ◽  
Structural Applications

This study focuses on the flexural behavior of pultruded glass fiber-reinforced polymer (GFRP) profiles developed for structural applications. Fiber content is a commonly accepted measure for estimating the resistance of such components, and technical datasheets describe this essential parameter. However, its direct implementation to the numerical simulations can face substantial problems because of the limitations of standard test protocols. Furthermore, the fiber mass percentage understandable for producers is unsuitable for typical software considered the volumetric reinforcement content. This manuscript exemplifies the above situation both experimentally and analytically, investigating two GFRP square hollow section (SHS) profiles available at the market. A three-point bending test determines the mechanical performance of the profiles in this experimental program; a digital image correlation system captures deformations and failure mechanisms of the SHS specimens; a standard tensile test defines the material properties. A simplified finite element (FE) model is developed based on the smeared reinforcement concept to predict the stiffness and load-bearing capacity of the profiles. An efficient balance between the prediction accuracy and computation time characterizes the developed FE approach that does not require specific descriptions of reinforcement geometry and refined meshes necessary for modeling the discrete fibers. The proposed FE approach is also used to analyze the fiber efficiency in reinforcing the polymer matrix. The efficiency is understood as the model’s ability to resist mechanical load proportional to the dry filaments’ content and experimental elastic modulus value. Scanning electron microscopy relates the composite microstructure and the mechanical performance of the selected profiles in this study.

scholarly journals Study on Strength and Stiffness of WC-Co-NiCr Graded Samples

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4166
Author(s):  
Leszek Czechowski
Keyword(s):  
Chemical Elements ◽  
Numerical Approach ◽  
Functionally Graded ◽  
Bending Test ◽  
Layer By Layer ◽  
Total Strength ◽  
Thin Walled Structures ◽  
Layer Deposition ◽  
Graded Material ◽  
Detonation Gun

This work deals with the investigation of the strength and the stiffness of samples built of step-variable functionally graded material (FGM). The considered FGM samples consist of two main components: WC and NiCr with some content of Co as a conjunction of structure. The samples were fabricated on the basis of the detonation gun layer deposition method which is regarded as a novelty in the case of FGM production. The analyzed samples possess a finite number of layers with different varying fractions of each constituent across the wall. The basic tests of bending were conducted to assess the influence of used components in adequate proportions on the stiffness and the total strength in bending. In addition, to validate the numerical approach, simulations of samples under similar loads with truly reflected material distributions were carried out. The material properties of components were determined due to micro-nano-hardness by instrumental indentation techniques. The numerical calculations were performed with the use of the material characteristics for each material and with a consideration of large deflections. Furthermore, by means of an electron microscope, the composition of materials and distribution of chemical elements across the thickness of samples were examined. This paper reveals the experimental results of FGM samples manufactured by detonation gun layer deposition which allows the creation of layer by layer moderately thin-walled structures. It was shown that the indentation method of a determination of Young’s modulus gave higher values in comparison to values attained in the bending test. Moreover, it was stated that a modelling of FGM still requires the study of each layer separately to clearly predict the strength of the whole FGM structure.

The Effect of β-SiC Nanowires on the Properties of Al2O3 Composites

2016 ◽  
Vol 690 ◽  
pp. 240-245
Author(s):  
Wasana Khongwong ◽  
Chumphol Busabok
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Flexural Strength ◽  
Bending Test ◽  
Matrix Composites ◽  
Sic Nanowires ◽  
Four Point Bending ◽  
Four Point Bending Test ◽  
Cold Pressed ◽  
The Relationship

To investigate the effect of adding b-SiC nanowires on the properties of the Al2O3 matrix composites, four different amounts of SiC nanowires, 0.05, 0.1, 0.2 and 0.25 wt% were mixed with Al2O3 powder. All mixtures were ball-milled and dried in an oven at a temperature of 120°C. The Al2O3-SiC mixtures were uniaxially pressed into pellets under 5 MPa and were then isostatically cold-pressed (CIP) under a pressure of 200 MPa. Specimens (13 mm in diameter and 2.5 mm in thickness) were sintered in a tube furnace at the temperature of 1400°C for 1 h in Ar atmosphere. Physical and thermal properties of pellet composites were characterized. The bar shape specimens with dimension of 3 mm x 4 mm x 35 mm were prepared for four-point bending test. The relationship between thermal conductivity and flexural strength versus grain connection of composites have been investigated. The results showed that the composites with adding SiC nanowires at 0.05-0.2 wt% possessed lower thermal conductivity than those monolithic Al2O3 specimens. However, the thermal conductivity of the composite specimens with 0.25 wt% SiC nanowires became higher than those of monolithic Al2O3 specimens. The flexural strengths of the composites gradually decreased with the increasing amount of SiC nanowires.

High Temperature Mechanical Properties of a Crystallized BaO-B2O3-Al2O3-SiO2 Glass Ceramic for SOFC

2009 ◽  
Author(s):  
Hsiu-Tao Chang ◽  
Chih-Kuang Lin ◽  
Chien-Kuo Liu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Stress Relaxation ◽  
Flexural Strength ◽  
Glass Ceramic ◽  
Testing Temperature ◽  
Bending Test ◽  
High Temperature Mechanical Properties ◽  
Four Point Bending ◽  
The Given

The high temperature mechanical properties in a glass-ceramic sealant of BaO-B2O3-Al2O3-SiO2 system was studied by four-point bending test at room temperature, 550°C, 600°C, 650°C, and 700°C, to investigate the variation of Young’s modulus, flexural strength, and stress relaxation. Weibull statistic analysis was applied to describe the fracture strength of the given glass ceramic. The crystalline phase was produced by controlled heat treatment and analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the flexural strength was enhanced at high temperatures when the testing temperature was below the glass transition temperature (Tg). This was presumably due to a crack healing effect taking place at high temperature. Significant stress relaxation for the given glass ceramic was observed to generate extremely large deformation without breaking the specimens when the testing temperature was set at 700°C.

Thermo-Mechanical Analysis of Functionally Graded Material Plate under Transverse Loading for Varying Volume Gradation

2019 ◽  
Vol 1155 ◽  
pp. 81-88
Author(s):  
Vyom Shah ◽  
Darshita Shah ◽  
Dhaval B. Shah
Keyword(s):  
Flat Plate ◽  
Functionally Graded Material ◽  
Material Properties ◽  
Sandwich Plate ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Functionally Graded ◽  
Von Mises Stress ◽  
Graded Material ◽  
Matlab Programming

Functionally graded material (FGM) has a unique design in which material properties vary smoothly and continuously which leads to having better thermal and mechanical performance. Functionally graded material has a wide area of application from the pressure vessel to aerospace due to its tailoring properties. The main emphasis has been made here, to present a structural mechanical and steady-state thermal analysis of functionally graded flat plate made up of aluminum and ceramic. The flat plate is subjected to various boundary and loading condition. Material properties of FGM is calculated across the thickness using power law with the help of MATLAB programming. An analysis is performed for various volume gradation using MACROS in ANSYS APDL. The analysis results for functionally graded materials are compared with a composite sandwich plate for the same boundary conditions. It was found that von-Mises stress generated in FGM is 14.6% less than compared to sandwich structure, the stress in x and y-direction is 16.5% less, XY-Shear is 13.5% less and deflection is 33% less than a sandwich plate of aluminum and ceramic.

scholarly journals Reliability of Different Bending Test Methods for Dental Press Ceramics

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5162
Author(s):  
Daisuke Miura ◽  
Yoshiki Ishida ◽  
Taira Miyasaka ◽  
Harumi Aoki ◽  
Akikazu Shinya
Keyword(s):  
Flexural Strength ◽  
Testing Machine ◽  
Test Methods ◽  
Bending Test ◽  
Biaxial Bending ◽  
Bending Tests ◽  
Four Point Bending ◽  
Biaxial Tests ◽  
Biaxial Flexural Strength ◽  
Flexural Tests

Objective: This study investigates the reliability of different flexural tests such as three-point-bending, four-point bending, and biaxial tests, in strengthening the dental pressed ceramics (DPCs) frequently used in clinical applications. Methods: The correlations between the three types of bending tests for DPCs were investigated. Plate-shaped specimens for the three-point and four-point bending tests and a disc-shaped specimen for the biaxial bending test were prepared. Each bending test was conducted using a universal testing machine. Results: The results for six DPCs showed that the flexural strength in descending order were the three-point flexural strength, biaxial flexural strength, and four-point flexural strength, respectively. Then, a regression analysis showed a strong correlation between each of the three test methods, with the combination of four-point and biaxial flexural strength showing the highest values. The biaxial flexural strength was not significantly different in the Weibull coefficient (m) compared to the other tests, with the narrowest range considering the 95% interval. The biaxial bending test was found to be suitable for materials with small plastic deformation from the yield point to the breaking point, such as DPCs.

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