Re-examination of the mechanical anisotropy of porcine thoracic aorta by uniaxial tensile tests

Abstract Heart disease is the second leading cause of death in Canada resulting in $20.9 billion annual healthcare expenditures [1,2]. Understanding the mechanics of the human descending thoracic aorta is fundamental for comprehending the development of pathologies and improving surgical prostheses. This study presents hyperelastic and viscoelastic material characterizations of the human descending thoracic aorta from twelve different donors, with a mean age of 49.4 years. The specimens were dissected into the three constituent layers: intima, media and adventitia. Evaluating the layer-specific opening angles led to the computation of the circumferential residual stresses. Uniaxial tensile tests of each layer, in both the circumferential and axial direction, were used to model the hyperelastic behavior according to the Gasser-Ogden-Holzapfel model (GOH). The storage modulus and loss tangent for the layers were obtained from uniaxial harmonic excitations at varied frequencies, to model the viscoelastic behavior with the generalized Maxwell model. The results showed a positive correlation between age and stiffness for all layers, both axially and circumferentially. Similar loss tangent values were found across the three layers. A large increase in the storage modulus from static to dynamic experiments further corroborates the importance of a viscoelastic model of the aorta, rather than solely hyperelastic.

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Effects of the crystallographic texture on the contractile strain ratio of Ti–3Al–2.5V tubing

Journal of Applied Crystallography ◽

10.1107/s1600576720001879 ◽

2020 ◽

Vol 53 (2) ◽

pp. 419-423

Author(s):

Wenrui Wang ◽

Lihong Yuan ◽

Yun Li ◽

Hui Zhang ◽

Wangfeng Zhang ◽

...

Keyword(s):

Volume Fraction ◽

Strain Ratio ◽

Tensile Tests ◽

Orientation Distribution ◽

Distribution Functions ◽

Mechanical Anisotropy ◽

Control Factor ◽

Uniaxial Tensile ◽

Euler Angles ◽

Tangential Plane

The contractile strain ratio (CSR) is an important property and a quality control factor of cold-worked and stress-relieved Ti–3Al–2.5V tubing. In this work, the CSR values of three thin-walled Ti–3Al–2.5V tubing samples were obtained by uniaxial tensile tests, and the crystallographic textures of the tubing samples were characterized by orientation distribution functions (ODFs) which were determined on the basis of a series of pole figures obtained by X-ray diffraction. A quantitative method is proposed for exploring the correlation between the CSR values and the ODF data of the tubing samples, including the following steps: Firstly, taking advantage of the ODF data, the volume fraction (V%) of crystallites that lie within a certain range of Euler angles (φ1, Φ, φ2) can be calculated, and the calculation is performed on each set of Euler angles (φ1, Φ, φ2). Secondly, each V% is resolved into an effective fraction in the orientation of the ideal radial texture {0002}〈10\overline 10〉 corresponding to the Euler angles of (0, 0, 0), and the equivalent radial texture (ERT) is obtained as the sum of all such effective fractions. Thirdly, similarly to the previous step, the equivalent tangential texture (ETT) is calculated. The CSR will be related to the ratio of the ERT to the ETT, named the equivalent texture ratio (ETR). The CSR values of the tubing samples are 1.38, 1.96 and 2.19 and their ETR values are 1.33, 1.72 and 1.87, respectively. In particular, the CSR and the ETR of the tubing with a random distribution of the basal poles in the radial–tangential plane are both unity. It is found from the above data that the CSR increases approximately linearly with the ETR. Since the three-dimensional orientations of crystallites and the orientation distributions throughout the Euler space are taken into account in the calculations of the ETR, the proposed method can be used for predicting and explaining the mechanical anisotropy of Ti–3Al–2.5V tubing more accurately.

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Texture Selection Mechanisms during Recrystallization and Grain Growth of a Magnesium-Erbium-Zinc Alloy

Metals ◽

10.3390/met11010171 ◽

2021 ◽

Vol 11 (1) ◽

pp. 171

Author(s):

Fatim-Zahra Mouhib ◽

Fengyang Sheng ◽

Ramandeep Mandia ◽

Risheng Pei ◽

Sandra Korte-Kerzel ◽

...

Keyword(s):

Grain Growth ◽

Ternary Alloy ◽

Solute Drag ◽

Tensile Tests ◽

Electron Back Scatter Diffraction ◽

Zinc Alloy ◽

Uniaxial Tensile ◽

Microstructural Stability ◽

Solid Solution Strengthening ◽

Zener Drag

Binary and ternary Mg-1%Er/Mg-1%Er-1%Zn alloys were rolled and subsequently subjected to various heat treatments to study texture selection during recrystallization and following grain growth. The results revealed favorable texture alterations in both alloys and the formation of a unique ±40° transvers direction (TD) recrystallization texture in the ternary alloy. While the binary alloy underwent a continuous alteration of its texture and grain size throughout recrystallization and grain growth, the ternary alloy showed a rapid rolling (RD) to transvers direction (TD) texture transition occurring during early stages of recrystallization. Targeted electron back scatter diffraction (EBSD) analysis of the recrystallized fraction unraveled a selective growth behavior of recrystallization nuclei with TD tilted orientations that is likely attributed to solute drag effect on the mobility of specific grain boundaries. Mg-1%Er-1%Zn additionally exhibited a stunning microstructural stability during grain growth annealing. This was attributed to a fine dispersion of dense nanosized particles in the matrix that impeded grain growth by Zener drag. The mechanical properties of both alloys were determined by uniaxial tensile tests combined with EBSD assisted slip trace analysis at 5% tensile strain to investigate non-basal slip behavior. Owing to synergic alloying effects on solid solution strengthening and slip activation, as well as precipitation hardening, the ternary Mg-1%Er-1%Zn alloy demonstrated a remarkable enhancement in the yield strength, strain hardening capability, and failure ductility, compared with the Mg-1%Er alloy.

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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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A Flow Stress Model of 300M Steel for Isothermal Tension

Materials ◽

10.3390/ma14020252 ◽

2021 ◽

Vol 14 (2) ◽

pp. 252

Author(s):

Rongchuang Chen ◽

Shiyang Zhang ◽

Xianlong Liu ◽

Fei Feng

Keyword(s):

Flow Stress ◽

Constitutive Model ◽

Tensile Deformation ◽

Flow Behavior ◽

Tensile Tests ◽

Uniaxial Tensile ◽

Model Parameters ◽

Average Deviation ◽

Cross Sectional ◽

300M Steel

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.

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Experimental Investigation of Ti-6Al-4V with a Biaxial Tensile Test Setup at Elevated Temperature

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.622-623.273 ◽

2014 ◽

Vol 622-623 ◽

pp. 273-278 ◽

Cited By ~ 1

Author(s):

Marion Merklein ◽

Sebastian Suttner ◽

Adam Schaub

Keyword(s):

Elevated Temperature ◽

Elevated Temperatures ◽

Tensile Tests ◽

Advanced Materials ◽

Uniaxial Tensile ◽

Plastic Yielding ◽

Characterization Methods ◽

Specific Strength ◽

Biaxial Tensile ◽

Stress States

The requirement for products to reduce weight while maintaining strength is a major challenge to the development of new advanced materials. Especially in the field of human medicine or aviation and aeronautics new materials are needed to satisfy increasing demands. Therefore the titanium alloy Ti-6Al-4V with its high specific strength and an outstanding corrosion resistance is used for high and reliable performance in sheet metal forming processes as well as in medical applications. Due to a meaningful and accurate numerical process design and to improve the prediction accuracy of the numerical model, advanced material characterization methods are required. To expand the formability and to skillfully use the advantage of Ti-6Al-4V, forming processes are performed at elevated temperatures. Thus the investigation of plastic yielding at different stress states and at an elevated temperature of 400°C is presented in this paper. For this reason biaxial tensile tests with a cruciform shaped specimen are realized at 400°C in addition to uniaxial tensile tests. Moreover the beginning of plastic yielding is analyzed in the first quadrant of the stress space with regard to complex material modeling.

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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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Correlation among Microstructure, Texture, and Properties along the Thickness Direction in As-Hot-Rolled and As-Solution-Quenched Al7055 Thick Plates

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1026.65 ◽

2021 ◽

Vol 1026 ◽

pp. 65-73

Author(s):

Kai Zhu ◽

Hong Wei Yan

Keyword(s):

Mechanical Properties ◽

Yield Strength ◽

Tensile Tests ◽

Rolled Plate ◽

Uniaxial Tensile ◽

Thickness Direction ◽

Electron Backscattered Diffraction ◽

Thick Plates ◽

Aluminum Plates ◽

Hot Rolled

Both microstructure inhomogeneity and mechanical property diversity along the thickness direction in rolled thick aluminum plates have been considered to have a remarkable impact on the performance and properties of the products made from the plates. In this study, scanning electron microscopy (SEM) and electron backscattered diﬀraction (EBSD) characterizations of microstructure and texture types along the thickness directions of Al7055 thick plate specimens prepared using two conditions, hot-rolling and solution-quenching, were performed. To examine the mechanical properties, uniaxial tensile tests were also carried out on specimens machined from both types of thick plates, using a layered strategy along the thickness direction. The results indicate that both the microstructure and mechanical properties are inhomogeneous under the two conditions. Furthermore, it is evident that there is a hereditary relationship between the mechanical properties of the two plates—areas with higher yield strength in the as-hot-rolled plate correspond to areas with the higher yield strength in the as-solution-quenched plate

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