CARDIFRC®– Development and mechanical properties. Part III: Uniaxial tensile response and other mechanical properties

AbstractAdditive manufacturing (AM), and in particular selective laser melting (SLM) technology, allows to produce structural components made of lattice structures. These kinds of structures have received a lot of research attention over recent years due to their capacity to generate easy-to-manufacture and lightweight components with enhanced mechanical properties. Despite a large amount of work available in the literature, the prediction of the mechanical behavior of lattice structures is still an open issue for researchers. Numerical simulations can help to better understand the mechanical behavior of such a kind of structure without undergoing long and expensive experimental campaigns. In this work, we compare numerical and experimental results of a uniaxial tensile test for stainless steel 316L octet-truss lattice specimen. Numerical simulations are based on both the nominal as-designed geometry and the as-build geometry obtained through the analysis of µ-CT images. We find that the use of the as-build geometry is fundamental for an accurate prediction of the mechanical behavior of lattice structures.

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Experimental investigation of the mechanical behavior of glass fiber/high fluidity polyamide-based composites for automotive market

Journal of Reinforced Plastics and Composites ◽

10.1177/07316844211014006 ◽

2021 ◽

pp. 073168442110140

Author(s):

Hossein Ramezani-Dana ◽

Moussa Gomina ◽

Joël Bréard ◽

Gilles Orange

Keyword(s):

Mechanical Properties ◽

Glass Fiber ◽

Mechanical Performance ◽

Physical And Mechanical Properties ◽

Ultimate Strain ◽

Uniaxial Tensile ◽

Compression Tests ◽

Automotive Market ◽

Glass Fiber Reinforced ◽

Glass Fiber Reinforcement

In this work, we examine the relationships between the microstructure and the mechanical properties of glass fiber–reinforced polyamide 6,6 composite materials ( V f = 54%). These materials made by thermocompression incorporate different grades of high fluidity polyamide-based polymers and two types of quasi-UD glass fiber reinforcement. One is a classic commercial fabric, while the other specially designed and manufactured incorporates weaker tex glass yarns (the spacer) to increase the planar permeability of the preform. The effects of the viscosity of the polymers and their composition on the wettability of the reinforcements were analyzed by scanning electron microscopy observations of the microstructure. The respective influences of the polymers and the spacer on the mechanical performance were determined by uniaxial tensile and compression tests in the directions parallel and transverse to the warp yarns. Not only does the spacer enhance permeability but it also improves physical and mechanical properties: tensile longitudinal Young’s modulus increased from 38.2 GPa to 42.9 GPa (13% growth), tensile strength increased from 618.9 MPa to 697 MPa (3% growth), and decrease in ultimate strain from 1.8% to 1.7% (5% reduction). The correlation of these results with the damage observed post mortem confirms those acquired from analyses of the microstructure of composites and the rheological behaviors of polymers.

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Water Influence on the Uniaxial Tensile Behavior of Polytetrafluoroethylene-Coated Glass Fiber Fabric

Materials ◽

10.3390/ma14040846 ◽

2021 ◽

Vol 14 (4) ◽

pp. 846

Author(s):

Hastia Asadi ◽

Joerg Uhlemann ◽

Natalie Stranghoener ◽

Mathias Ulbricht

Keyword(s):

Mechanical Properties ◽

Glass Fiber ◽

Operation Time ◽

Uniaxial Tensile ◽

Membrane Structures ◽

Strength Deterioration ◽

Coated Glass ◽

Reversible Loss ◽

The Impact ◽

Loss Of Strength

Polytetrafluoroethylene (PTFE)-coated glass fiber fabrics are used for long-lasting membrane structures due to their outstanding mechanical properties, chemical stabilities, and satisfying service life. During their operation time, different environmental impacts might influence their performance, especially regarding the mechanical properties. In this contribution, the impact of water on the tensile strength deterioration was assessed experimentally, providing evidence of considerable but partially reversible loss of strength by up to 20% among the various types of investigated industrially established fabrics.

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Comprehensive study on mechanical properties of coated biaxial warp-knitted fabrics

Journal of Reinforced Plastics and Composites ◽

10.1177/07316844211020499 ◽

2021 ◽

pp. 073168442110204

Author(s):

Bin Yang ◽

Yingying Shang ◽

Zeliang Yu ◽

Minger Wu ◽

Youji Tao ◽

...

Keyword(s):

Mechanical Properties ◽

Failure Modes ◽

Least Squares Method ◽

Tensile Tests ◽

Tensile Creep ◽

Base Layer ◽

Sustained Load ◽

Uniaxial Tensile ◽

Membrane Structures ◽

Knitted Fabrics

In recent years, coated fabrics have become the major material used in membrane structures. Due to the special structure of base layer and mechanical properties, coated biaxial warp-knitted fabrics are increasingly applied in pneumatic structures. In this article, the mechanical properties of coated biaxial warp-knitted fabrics are investigated comprehensively. First, off-axial tensile tests are carried out in seven in-plane directions: 0°, 15°, 30°, 45°, 60°, 75°, and 90°. Based on the stress–strain relationship, tensile strengths are obtained and failure modes are studied. The adaptability of Tsai–Hill criterion is analyzed. Then, the uniaxial tensile creep test is performed under 24-h sustained load and the creep elongation is calculated. Besides, tearing strengths in warp and weft directions are obtained by tearing tests. Finally, the biaxial tensile tests under five different load ratios of 1:1, 2:1, 1:2, 1:0, and 0:1 are carried out, and the elastic constants and Poisson’s ratio are calculated using the least squares method based on linear orthotropic assumption. Moreover, biaxial specimens under four load ratios of 3:1, 1:3, 5:1, and 1:5 are further tensile tested to verify the adaptability of linear orthotropic model. These experimental data offer a deeper and comprehensive understanding of mechanical properties of coated biaxial warp-knitted fabrics and could be conveniently adopted in structural design.

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Investigation of Damage Evolution in Heterogeneous Rock Based on the Grain-Based Finite-Discrete Element Model

Materials ◽

10.3390/ma14143969 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3969

Author(s):

Shirui Zhang ◽

Shili Qiu ◽

Pengfei Kou ◽

Shaojun Li ◽

Ping Li ◽

...

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Tensile Strength ◽

Grain Orientation ◽

Damage Evolution ◽

Discrete Element ◽

Uniaxial Tensile ◽

Tensile Cracks ◽

Rock Heterogeneity ◽

Heterogeneous Rock

Granite exhibits obvious meso-geometric heterogeneity. To study the influence of grain size and preferred grain orientation on the damage evolution and mechanical properties of granite, as well as to reveal the inner link between grain size‚ preferred orientation, uniaxial tensile strength (UTS) and damage evolution, a series of Brazilian splitting tests were carried out based on the combined finite-discrete element method (FDEM), grain-based model (GBM) and inverse Monte Carlo (IMC) algorithm. The main conclusions are as follows: (1) Mineral grain significantly influences the crack propagation paths, and the GBM can capture the location of fracture section more accurately than the conventional model. (2) Shear cracks occur near the loading area, while tensile and tensile-shear mixed cracks occur far from the loading area. The applied stress must overcome the tensile strength of the grain interface contacts. (3) The UTS and the ratio of the number of intergrain tensile cracks to the number of intragrain tensile cracks are negatively related to the grain size. (4) With the increase of the preferred grain orientation, the UTS presents a “V-shaped” characteristic distribution. (5) During the whole process of splitting simulation, shear microcracks play the dominant role in energy release; particularly, they occur in later stage. This novel framework, which can reveal the control mechanism of brittle rock heterogeneity on continuous-discontinuous trans-scale fracture process and microscopic rock behaviour, provides an effective technology and numerical analysis method for characterizing rock meso-structure. Accordingly, the research results can provide a useful reference for the prediction of heterogeneous rock mechanical properties and the stability control of engineering rock masses.

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Effect of PWHT on the Microstructure and Mechanical Properties of Friction Stir Welded DP780 Steel

Metals ◽

10.3390/met11071097 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1097

Author(s):

Umer Masood Chaudry ◽

Seung-Chang Han ◽

Fathia Alkelae ◽

Tea-Sung Jun

Keyword(s):

Mechanical Properties ◽

Annealing Temperature ◽

Tensile Elongation ◽

Image Correlation ◽

Frictional Heat ◽

Uniaxial Tensile ◽

Uniaxial Tensile Test ◽

Friction Stir ◽

Microstructure And Mechanical Properties ◽

Dp780 Steel

In the present study, the effect of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of friction stir welded (FSW) DP780 steel sheets was investigated. FSW was carried out at a constant tool rotation speed of 400 rpm and different welding speeds (200 mm/min and 400 min/min). A defect free weld was witnessed for both of the welding conditions. The mutual effect of severe plastic deformation and frictional heat generation by pin rotation during the FSW process resulted in grain refinement due to dynamic recrystallization in the stir zone (SZ) and thermo-mechanically affected zone (TMAZ). Lower tensile elongation and higher yield and ultimate tensile strengths were recorded for welded-samples as compared to the base material (BM) DP780 steel. The joints were subsequently annealed at various temperatures at 450–650 °C for 1 h. At higher annealing temperature, the work hardening rate of joints gradually decreased and subsequently failed in the softened heat-affected zone (HAZ) during the uniaxial tensile test. Reduction in yield strength and tensile strength was found in all PWHT conditions, though improvement in elongation was achieved by annealing at 550 °C. The digital image correlation analysis showed that an inhomogeneous strain distribution occurred in the FSWed samples, and the strain was particularly highly localized in the advancing side of interface zone. The nanoindentation measurements covering the FSWed joint were consistent with an increase of the annealing temperature. The various grains size in the BM, TMAZ, and SZ is the main factor monitoring the hardness distribution in these zones and the observed discrepancies in mechanical properties.

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Atomic Simulations of Packing Structures, Local Stress and Mechanical Properties for One Silicon Lattice with Single Vacancy on Heating

Materials ◽

10.3390/ma14113127 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3127

Author(s):

Feng Dai ◽

Dandan Zhao ◽

Lin Zhang

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

Young's Modulus ◽

Silicon Crystal ◽

Local Stress ◽

Uniaxial Tensile ◽

Single Vacancy ◽

Vacancy Defects ◽

Silicon Lattice ◽

Atomic Simulations

The effect of vacancy defects on the structure and mechanical properties of semiconductor silicon materials is of great significance to the development of novel microelectronic materials and the processes of semiconductor sensors. In this paper, molecular dynamics is used to simulate the atomic packing structure, local stress evolution and mechanical properties of a perfect lattice and silicon crystal with a single vacancy defect on heating. In addition, their influences on the change in Young’s modulus are also analyzed. The atomic simulations show that in the lower temperature range, the existence of vacancy defects reduces the Young’s modulus of the silicon lattice. With the increase in temperature, the local stress distribution of the atoms in the lattice changes due to the migration of the vacancy. At high temperatures, the Young’s modulus of the silicon lattice changes in anisotropic patterns. For the lattice with the vacancy, when the temperature is higher than 1500 K, the number and degree of distortion in the lattice increase significantly, the obvious single vacancy and its adjacent atoms contracting inward structure disappears and the defects in the lattice present complex patterns. By applying uniaxial tensile force, it can be found that the temperature has a significant effect on the elasticity–plasticity behaviors of the Si lattice with the vacancy.

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Application of Small Punch Test to Evaluate Tensile Properties of SA213T22 Grade Boiler Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.830-831.191 ◽

2015 ◽

Vol 830-831 ◽

pp. 191-194

Author(s):

M. Venkateswara Rao

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Tensile Properties ◽

Test Methods ◽

Uniaxial Tensile ◽

Test Results ◽

Small Punch Test ◽

Small Punch ◽

Punch Test ◽

Aging Phenomena

Conventional tensile test methods are used for service exposed high temperature boiler tubes to evaluate the deterioration in mechanical properties such as tensile strength, yield strength and percentage elongation. The mechanical properties are required to be evaluated periodically as the boiler components undergo material degradation due to aging phenomena. The aging phenomena occurs due to continuous exposure of tubes to high temperature & pressure steam prevailing inside the tubes and high temperature exposure to corrosive combustible gases from the external surfaces within the boiler.A recent developed new technique called small punch testing has been used to evaluate the tensile properties of SA 213T22 grade steel predominantly exists in super-heater and re-heater sections of boiler. The small punch tests have been carried out on the miniature disk shaped specimens of diameter of 8.0 mm and 0.5 mm thickness extracted from both the new and service exposed tubes. Conventional uniaxial tensile tests on standard specimens from the same tube material have also been performed for comparison. The service exposed tubes showed considerable loss in mechanical properties in both the conventional and small punch test results. Correlations of tensile properties have been obtained based on the comparative analysis of both small punch and uniaxial tensile test results. Further, the study showed that an appropriate empirical relation could be generated for new and service exposed materials between both the techniques. Conventional test methods require large quantity of material removal for test samples from in-service components whereas small punch test method needs only a miniature sample extraction. This small punch test technique could also be extended to evaluate the thicker section boiler components such as pipelines and headers in the boiler as a part of remaining life assessment study. Also this technique could be a useful tool to any metallic component where large quantity of sample removal may be difficult or may not be feasible.

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Effect of Polyvinyl Alcohol Concentration on the Mechanical Properties of Collagen/Polyvinyl Alcohol Blends

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.732.161 ◽

2015 ◽

Vol 732 ◽

pp. 161-164 ◽

Cited By ~ 5

Author(s):

Jan Vesely ◽

Lukas Horny ◽

Hynek Chlup ◽

Milos Beran ◽

Milan Krajicek ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Stress ◽

Polyvinyl Alcohol ◽

Modulus Of Elasticity ◽

Tensile Tests ◽

Ultimate Tensile Stress ◽

Alcohol Concentration ◽

Uniaxial Tensile ◽

Initial Modulus ◽

Water Saturated

The effects of the polyvinyl alcohol (PVA) concentration on mechanical properties of hydrogels based on blends of native or denatured collagen / PVA were examined. Blends of PVA with collagen were obtained by mixing the solutions in different ratios, using glycerol as a plasticizer. The solutions were cast on polystyrene plates and the solvent was allowed to evaporate at room temperature. Uniaxial tensile tests were performed in order to obtain the initial modulus of elasticity (up to deformation 0.1), the ultimate tensile stress and the deformation at failure of the material in the water-saturated hydrogel form. It was found that the material was elastic and the addition of PVA helped to enhance both the ultimate tensile stress and modulus of elasticity of the films. Samples prepared from denaturated collagen showed the higher ultimate tensile stress and the deformation at failure in comparison with those prepared from native collagen. The results suggest that we could expect successful application of the collagen/PVA biomaterial for tissue engineering.

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Mechanical properties of PVDF-coated fabric under tensile tests

Journal of Polymer Engineering ◽

10.1515/polyeng-2014-0087 ◽

2015 ◽

Vol 35 (4) ◽

pp. 377-390 ◽

Cited By ~ 11

Author(s):

Andrzej Ambroziak

Keyword(s):

Mechanical Properties ◽

Polyvinylidene Fluoride ◽

Cyclic Load ◽

Tensile Tests ◽

Woven Fabrics ◽

Uniaxial Tensile ◽

Cyclic Tests ◽

Comprehensive Investigation ◽

Coated Fabric ◽

Coated Fabrics

Abstract This article describes the laboratory tests necessary to identify the mechanical properties of the polyvinylidene fluoride (PVDF)-coated fabrics named Precontraint 1202S and Precontraint 1302S. First, a short survey of the literature concerning the description of coated woven fabrics is presented. Second, the material parameters for PVDF-coated fabrics are specified on the basis of biaxial tensile tests. A comparison of the 1:1 biaxial and the uniaxial tensile tests results is also given. Additionally, biaxial cyclic tests were performed to observe the change of immediate mechanical properties under cyclic load. The article is aimed as an introduction to a comprehensive investigation of the mechanical properties of coated fabrics.

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