Tensile Tests at GFRP Rebars

2021 ◽  
pp. 918-927
Author(s):  
André Weber ◽  
Christian Caspari ◽  
Matthias Pahn
Keyword(s):  
Tensile Tests ◽  
Gfrp Rebars

scholarly journals GFRP Bar: Determining Tensile Strength with Bending Test

2015 ◽  
Vol 1083 ◽  
pp. 90-96 ◽  
Author(s):  
Ana Almerich-Chulia ◽  
E. Fenollosa ◽  
I. Cabrera
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Small Diameter ◽  
Tensile Tests ◽  
Bending Test ◽  
Bending Tests ◽  
Reliable Test ◽  
Gfrp Bar ◽  
Gfrp Reinforcement ◽  
Gfrp Rebars

In order to obtain GFRP reinforcement bars it is necessary to undertake tests regulated code which require important mechanical tools. This paper presents a method which allows for determining GFRP rebars tensile strength value from their flexural strength value which has been obtained with a simple, inexpensive and reliable test. This method results will be verified by applying it to values obtained in a series of bending tests and comparing these results with values obtained in tensile tests. Values concordance for small diameter GFRP rebars is very good.

Calculation And Experimental Substantiation Of Optimal Design Of The Welded Joint Of Plates On Соver Plates

2020 ◽  
pp. 17-24
Keyword(s):  
Welded Joint ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Tensile Tests ◽  
Physical Nonlinearity ◽  
Steel Plates ◽  
Optimal Parameters ◽  
Actual Problem ◽  
Numerical Research ◽  
Cover Plates

The article is devoted to the actual problem of assigning optimal parameters for connecting steel plates on cover plates with angular welds that are widely used in construction practice. The article presents the results of a comprehensive study of operation of a welded assembly of the plates connection on cover plates. An algorithm is proposed for determining the optimal parameters of a welded joint with fillet welds on the cover plates, which makes it possible to obtain a strength balanced connection. The results of full-scale tensile tests of models were presented. These results confirmed the correctness of the assumed design assumptions, and made it possible to obtain a form of destruction, not characteristic and not described in the normative literature, expressed by cutting the main elements along the length of the overlap in the joint. The possibility of such a form of destruction was confirmed by the results of numerical research in a nonlinear formulation. The optimal parameters of the nodal welded joint determined by engineering calculation are confirmed by experimental studies, as well as by the results of numerical experiments on models of calculation schemes, taking into account the physical nonlinearity of the material operation. The obtained dependence for determining the bearing capacity of the joint by the cut-off mechanism and the expression for limiting the overlap length of the cover plates will make it possible to predict the nature of the fracture and design equally strong joints.

Regularities and properties of instrumented indentation diagrams obtained by ball-shaped indenter

2020 ◽  
Vol 86 (5) ◽  
pp. 43-51
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
P. V. Volkov ◽  
D. A. Zhgut
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Elastoplastic Deformation ◽  
Elastic Limit ◽  
Tensile Tests ◽  
Indentation Load ◽  
International Standards ◽  
Instrumented Indentation ◽  
Indentation Methods ◽  
Special Points

The history of appearance and the current state of instrumented indentation are briefly described. It is noted that the materials instrumented indentation methods using a pyramid and ball indenters are actively developing and are currently regulated by several Russian and international standards. These standards provide formulas for calculating the Young’s modulus and hardness at maximum indentation load. Instrumented indentation diagrams «load F – displacement α» of a ball indenter for metallic materials were investigated. The special points on the instrumented indentation diagrams «F – α» loading curves in the area of elastic into elastoplastic deformation transition, and in the area of stable elastoplastic deformation are revealed. A loading curve area with the load above which the dF/dα begins to decrease is analyzed. A technique is proposed for converting «F – α» diagrams to «unrestored Brinell hardness HBt – relative unrestored indent depth t/R» diagrams. The elastic and elastoplastic areas of «HBt – t/R» diagrams are described by equations obtained analytically and experimentally. The materials strain hardening parameters during ball indentation in the area of elastoplastic and plastic deformation are proposed. The similarity of «HBt – t/R» indentation diagram with the «stress σ – strain δ» tensile diagrams containing common zones and points is shown. Methods have been developed for determining hardness at the elastic limit, hardness at the yield strength, and hardness at the ultimate strength by instrumented indentation with the equations for their calculation. Experiments on structural materials with different mechanical properties were carried out by instrumented indentation. The values of hardness at the elastic limit, hardness at the yield strength and hardness at the ultimate strength are determined. It is concluded that the correlations between the elastic limit and hardness at the elastic limit, yield strength and hardness at the yield strength, ultimate tensile strength and hardness at the ultimate strength is more justified, since the listed mechanical characteristics are determined by the common special points of indentation diagrams and tensile tests diagrams.

The Formability and Elongation of Aluminum Alloys AA5083 and AA3003 for Micro-Truss Sandwiches Manufacturing

2020 ◽  
Vol 38 (9A) ◽  
pp. 1396-1405
Author(s):  
Arwa F. Tawfeeq ◽  
Matthew R. Barnett
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Cost Effective ◽  
Tensile Tests ◽  
Truss Structures ◽  
High Quality ◽  
Trade Off ◽  
Clad Layer ◽  
Higher Temperature ◽  
Different Shapes

The development in the manufacturing of micro-truss structures has demonstrated the effectiveness of brazing for assembling these sandwiches, which opens new opportunities for cost-effective and high-quality truss manufacturing. An evolving idea in micro-truss manufacturing is the possibility of forming these structures in different shapes with the aid of elevated temperature. This work investigates the formability and elongation of aluminum alloy sheets typically used for micro-truss manufacturing, namely AA5083 and AA3003. Tensile tests were performed at a temperature in the range of 25-500 ○C and strain rate in the range of 2x10-4 -10-2 s-1. The results showed that the clad layer in AA3003 exhibited an insignificant effect on the formability and elongation of AA3003. The formability of the two alloys was improved significantly with values of m as high as 0.4 and 0.13 for AA5083 and AA3003 at 500 °C. While the elongation of both AA5083 and AA3003 was improved at a higher temperature, the elongation of AA5083 was inversely related to strain rate. It was concluded that the higher the temperature is the better the formability and elongation of the two alloys but at the expense of work hardening. This suggests a trade-off situation between formability and strength. 

Über die mechanische Bedeutung der Holzstrahlen | The mechanical relevance of wood rays

2003 ◽  
Vol 154 (12) ◽  
pp. 498-503 ◽  
Author(s):  
Ingo Burgert
Keyword(s):  
Beech Wood ◽  
Tensile Tests ◽  
Deciduous Tree ◽  
Biological Design ◽  
Transverse Tensile ◽  
Radial Reinforcement ◽  
Radial Strength ◽  
Transverse Tensile Strength ◽  
Strength And Stiffness ◽  
Technical Solutions

Three investigations into the mechanical relevance of wood rays were combined for this article. The main objective was to show, that, apart from physiological functions, rays also significantly influence the radial strength and stiffness of wood. In the first approach twelve deciduous tree species with various proportions of fractions of rays were examined for their transverse tensile strength and stiffness. The second approach was based on the comparison of the radial mechanical properties of wood with a very high proportion of fraction of rays and beech wood with a normal volume. In these two investigations the mechanical relevance of rays could only be deduced indirectly. By isolating big rays of beech and carrying out tensile tests on the tissue, we found direct evidence for the mechanical relevance. The results are discussed with regard to their biomechanical relevance. The importance of a radial reinforcement for the wood is underlined. Moreover, the principle of multi-functionality in nature is emphasized in keeping with a possible transfer of biological design to technical solutions.

Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

scholarly journals Wastes from Agricultural Silage Film Recycling Line as a Potential Polymer Materials

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1383
Author(s):  
Jerzy Korol ◽  
Aleksander Hejna ◽  
Klaudiusz Wypiór ◽  
Krzysztof Mijalski ◽  
Ewelina Chmielnicka
Keyword(s):  
Vinyl Acetate ◽  
Thermal Performance ◽  
Mechanical Performance ◽  
Ethylene Vinyl Acetate ◽  
Tensile Tests ◽  
Solid Particles ◽  
Polymer Materials ◽  
Slight Reduction ◽  
Scanning Calorimetry ◽  
Crystallinity Degree

The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were modified with 2.5 wt % of commercially available compatibilizers. The mechanical and thermal performance of modified wastes were evaluated by tensile tests, thermogravimetric analysis, and differential scanning calorimetry. It was found that incorporation of such a small amount of modifiers may overcome the drawbacks caused by the presence of impurities. The incorporation of maleic anhydride-grafted compounds enhanced the tensile strength of wastes by 13–25%. The use of more ductile compatibilizers—ethylene-vinyl acetate and paraffin increased the elongation at break by 55–64%. The presence of compatibilizers also reduced the stiffness of materials resulting from the presence of solid particles. It was particularly emphasized for styrene-ethylene-butadiene-styrene and ethylene-vinyl acetate copolymers, which caused up to a 20% drop of Young’s modulus. Such effects may facilitate the further applications of analyzed wastes, e.g., in polymer film production. Thermal performance was only slightly affected by compatibilization. It caused a slight reduction in polyethylene melting temperatures (up to 2.8 °C) and crystallinity degree (up to 16%). For more contaminated materials, the addition of compatibilizers caused a minor reduction in the decomposition onset (up to 6 °C). At the same time, for the waste after three washing cycles, thermal stability was improved. Moreover, depending on the desired properties and application, materials do not have to go through the whole recycling line, simplifying the process, reducing energy and water consumption. The presented results indicate that it is possible to efficiently use the materials, which do not have to undergo the whole recycling process. Despite the presence of impurities, they could be applied in the manufacturing of products which do not require exceptional mechanical performance.

scholarly journals Characterization of Beeswax, Candelilla Wax and Paraffin Wax for Coating Cheeses

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 261
Author(s):  
Adolfo Bucio ◽  
Rosario Moreno-Tovar ◽  
Lauro Bucio ◽  
Jessica Espinosa-Dávila ◽  
Francisco Anguebes-Franceschi
Keyword(s):  
Physical And Mechanical Properties ◽  
Tensile Tests ◽  
Paraffin Wax ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Dimensional Changes ◽  
Ductile Behavior ◽  
Candelilla Wax

A study on the physical and mechanical properties of beeswax (BW), candelilla wax (CW), paraffin wax (PW) and blends was carried out with the aim to evaluate their usefulness as coatings for cheeses. Waxes were analyzed by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), permeability, viscosity, flexural and tensile tests and scanning electron microscopy. Cheeses were coated with the waxes and stored for 5 weeks at 30 °C. Measured parameters were weight, moisture, occurrence and degree of fractures, and dimensional changes. The crystal phases identified by XRD for the three waxes allowed them to determine the length of alkanes and the nonlinear compounds in crystallizable forms in waxes. FTIR spectra showed absorption bands between 1800 and 800 cm−1 related to carbonyls in BW and CW. In DSC, the onset of melting temperature was 45.5 °C for BW, and >54 °C for CW and PW. Cheeses coated with BW did not show cracks after storage. Cheeses coated with CW and PW showed microcraks, and lost weight, moisture and shrunk. In the flexural and tensile tests, BW was ductile; CW and PW were brittle. BW blends with CW or PW displays a semi ductile behavior. Cheeses coated with BW blends lost less than 5% weight during storage. The best waxes were BW and the blends.

scholarly journals Chemical and physical interactions of regenerated cellulose yarns and isocyanate-based matrix systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bernhard Ungerer ◽  
Ulrich Müller ◽  
Antje Potthast ◽  
Enrique Herrero Acero ◽  
Stefan Veigel
Keyword(s):  
Mechanical Performance ◽  
Tensile Force ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Size Exclusion ◽  
Regenerated Cellulose ◽  
Hydrolytic Cleavage ◽  
Yarn Twist ◽  
Exclusion Chromatography ◽  
Physical And Chemical

AbstractIn the development of structural composites based on regenerated cellulose filaments, the physical and chemical interactions at the fibre-matrix interphase need to be fully understood. In the present study, continuous yarns and filaments of viscose (rayon) were treated with either polymeric diphenylmethane diisocyanate (pMDI) or a pMDI-based hardener for polyurethane resins. The effect of isocyanate treatment on mechanical yarn properties was evaluated in tensile tests. A significant decrease in tensile modulus, tensile force and elongation at break was found for treated samples. As revealed by size exclusion chromatography, isocyanate treatment resulted in a significantly reduced molecular weight of cellulose, presumably owing to hydrolytic cleavage caused by hydrochloric acid occurring as an impurity in pMDI. Yarn twist, fibre moisture content and, most significantly, the chemical composition of the isocyanate matrix were identified as critical process parameters strongly affecting the extent of reduction in mechanical performance. To cope with the problem of degradative reactions an additional step using calcium carbonate to trap hydrogen ions is proposed.

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