Development of a macro-element model for rockfall steel wires using

This paper aims to present a few aspects of the development of a plastic-hardening macro-element model for steel wires in flexible protection systems. First, the material behaviour is obtained using uniaxial tensile tests. Successively, the evolution of the elastic and plastic domain is obtained using a combination of physical tests, analytical models, and numerical simulations. Finally, the results obtained with the macro-element model are compared to those obtained using other approaches found in literature.

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A non-associative macro-element model for vertical plate anchors in clay

Canadian Geotechnical Journal ◽

10.1139/cgj-2020-0314 ◽

2021 ◽

Cited By ~ 1

Author(s):

Anderson Peccin da Silva ◽

Andrea Diambra ◽

Dimitrios K. Karamitros ◽

Shiao Huey Chow

Keyword(s):

Peak Load ◽

Element Model ◽

Offshore Structures ◽

Model Parameters ◽

Hardening Rule ◽

Pull Out ◽

Proposed Model ◽

Plastic Potential ◽

Plastic Hardening ◽

Macro Element

This work proposes a new plastic hardening, non-associative macro-element model to predict the behaviour of anchors in clay for floating offshore structures during keying and up to the peak load. Building on available models for anchors, a non-associated plastic potential is introduced to improve prediction of anchor trajectory and loss of embedment at peak conditions for a large range of padeye offsets and different pull-out directions. The proposed model also includes a displacement-hardening rule to simulate the force and displacement mobilisation at the early stages of the keying process. The model is challenged and validated against different sets of numerical and centrifuge data. This extensive validation process revealed that two of the four newly introduced model parameters assume a constant value for the range of simulated cases. This suggests that only two of the newly introduced parameters may need to be calibrated for the use of the proposed macro-element model in practice.

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Formability Analysis and Oxidation Layer Effects in Dieless Drawing of Stainless Steel Wires

Metals ◽

10.3390/met9080828 ◽

2019 ◽

Vol 9 (8) ◽

pp. 828 ◽

Cited By ~ 2

Author(s):

Hwang ◽

Liu

Keyword(s):

Finite Element ◽

Stainless Steel ◽

Element Model ◽

Tensile Tests ◽

Heat Transfer Analysis ◽

Finite Element Software ◽

Area Reduction ◽

Steel Wires ◽

Dieless Drawing ◽

Forming Temperature

In this study, dieless drawing experiments of stainless steel SUS304 wires of 1 mm in diameter were carried out using a self-developed dieless drawing machine. In order to prevent oxidation, argon gas was applied to a self-designed chamber during dieless drawing processes. The effects of the forming temperature and the oxide layer on the mechanical properties of the drawn SUS304 stainless wires obtained by tensile tests are discussed in this paper. A finite element model considering the high frequency induction heating mode in the finite element software DEFORM2D was developed to conduct the heat transfer analysis and the formability analysis of the drawn products in dieless drawing of stainless steel wires. The effects of the drawing speed and forming temperature on the maximal reachable area reductions are discussed. Through the comparisons of the maximal reachable area reduction between the finite element simulations and experiments, the finite element modelling for dieless drawing processes was validated.

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Mechanical Behaviour of TRC Composites: Experimental and Analytical Approaches

Applied Sciences ◽

10.3390/app9071492 ◽

2019 ◽

Vol 9 (7) ◽

pp. 1492 ◽

Cited By ~ 4

Author(s):

Marco Carlo Rampini ◽

Giulio Zani ◽

Matteo Colombo ◽

Marco di Prisco

Keyword(s):

Reinforced Concrete ◽

Mechanical Behaviour ◽

High Performance ◽

Tensile Tests ◽

Seismic Retrofitting ◽

Analytical Models ◽

Uniaxial Tensile ◽

Textile Reinforced Concrete ◽

Predictive Approaches ◽

Analytical Approaches

Textile reinforced concrete (TRC) is a promising high-performance material that has been employed with success in new constructions, as well as a strengthening layer of existing structural components. In this work, we document the optimisation procedure of textile-based composites for new construction and for the seismic retrofitting of under-reinforced concrete elements and masonry buildings. The study, aimed at maximising the material performances avoiding waste of economic resources, was addressed by means of a series of uniaxial tensile tests conducted on a wide set of alkali-resistant (AR) glass fabrics and TRCs. The samples differed in terms of cement-based matrices, embedded textiles and addition of dispersed microfibers. The results highlight the effects of fabric characteristics and introduction of short fibres on the mechanical behaviour, proposing novel comparison parameters based upon the load bearing capacity and the deformation response of the composites. The application of simplified analytical models borrowed from the literature finally revealed the limitations of the available predictive approaches, suggesting future lines of investigation.

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Finite element model and experimental studies on rubber-cord composite

Vietnam Journal of Mechanics ◽

10.15625/0866-7136/29/4/5605 ◽

2007 ◽

Vol 29 (4) ◽

pp. 551-561 ◽

Cited By ~ 1

Author(s):

Tran Huu Nam

Keyword(s):

Finite Element ◽

Experimental Studies ◽

Element Model ◽

Tensile Tests ◽

Rubber Matrix ◽

Uniaxial Tensile ◽

Fe Model ◽

Material Behaviour ◽

Mechanical Responses ◽

Cyclic Tension

The rubber-cord composite (CRC) which is created of rubber matrix reinforced with textile cords is used for many applications such as pneumatic membranes, automobile tires, pneumatic air-springs, hydraulic hoses and many others. The CRC is characterized by strongly anisotropic material behaviour and can simultaneously undergo large elastic deformations. In this paper a finite element (FE) model was developed and applied to study the mechanical responses of CRC. This model consists of 8-node hexahedral brick elements describing rubber matrix and 3-D spar elements for modeling of textile cords. The experimental studies in uniaxial and cyclic tension were performed. The material constants of textile cords were fitted to experimentally measured data by approach technique using linear and bilinear elastic models. The simulations of uniaxial tensile tests using proposed FE model were carried out. The numerical results of simulations were compared to experimental ones in order to verify the accurateness of the FE model. The obtained results indicated that the proposed FE model can be applied for the modeling and simulation of mechanical behaviour of CRC.

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Mechanical Stability of Hybrid Corrugated Sandwich Plates under Fluid-Structure-Thermal Coupling for Novel Thermal Protection Systems

Applied Sciences ◽

10.3390/app10082790 ◽

2020 ◽

Vol 10 (8) ◽

pp. 2790

Author(s):

Wenzheng Zhuang ◽

Chao Yang ◽

Zhigang Wu

Keyword(s):

Mechanical Stability ◽

Thermal Protection ◽

Element Model ◽

Parameter Study ◽

The Novel ◽

Thermal Coupling ◽

Mechanical Instability ◽

Fluid Structure ◽

Thermal Protection Systems ◽

Protection Systems

Hybrid corrugated sandwich (HCS) plates have become a promising candidate for novel thermal protection systems (TPS) due to their multi-functionality of load bearing and thermal protection. For hypersonic vehicles, the novel TPS that performs some structural functions is a potential method of saving weight, which is significant in reducing expensive design/manufacture cost. Considering the novel TPS exposed to severe thermal and aerodynamic environments, the mechanical stability of the HCS plates under fluid-structure-thermal coupling is crucial for preliminary design of the TPS. In this paper, an innovative layerwise finite element model of the HCS plates is presented, and coupled fluid-structure-thermal analysis is performed with a parameter study. The proposed method is validated to be accurate and efficient against commercial software simulation. Results have shown that the mechanical instability of the HCS plates can be induced by fluid-structure coupling and further accelerated by thermal effect. The influences of geometric parameters on thermal buckling and dynamic stability present opposite tendencies, indicating a tradeoff is required for the TPS design. The present analytical model and numerical results provide design guidance in the practical application of the novel TPS.

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Constitutive Models for the Tensile Behaviour of TRM Materials: Literature Review and Experimental Verification

Materials ◽

10.3390/ma14030700 ◽

2021 ◽

Vol 14 (3) ◽

pp. 700

Author(s):

Maria Concetta Oddo ◽

Giovanni Minafò ◽

Lidia La Mendola

Keyword(s):

State Of The Art ◽

Constitutive Models ◽

Stress Transfer ◽

Theoretical Models ◽

Tensile Tests ◽

Analytical Models ◽

Tensile Behaviour ◽

Tensile Response ◽

Textile Reinforced Mortar ◽

Inorganic Matrix

In recent years, the scientific community has focused its interest on innovative inorganic matrix composite materials, namely TRM (Textile Reinforced Mortar). This class of materials satisfies the need of retrofitting existing masonry buildings, by keeping the compatibility with the substrate. Different recent studies were addressed to improve the knowledge on their mechanical behaviour and some theoretical models were proposed for predicting the tensile response of TRM strips. However, this task is complex due to the heterogeneity of the constituent materials and the stress transfer mechanism developed between matrix and fabric through the interface in the cracked stage. This paper presents a state-of-the-art review on the existing constitutive models for the tensile behavior of TRM composites. Literature experimental results of tensile tests on TRM coupons are presented and compared with the most relevant analytical models proposed until now. Finally, a new experimental study is presented and its results are used to further verify the reliability of the literature expressions.

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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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Study of the Ultraviolet Effect and Thermal Analysis on Polypropylene Nonwoven Geotextile

Materials ◽

10.3390/ma14051080 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1080

Author(s):

Clever Aparecido Valentin ◽

Marcelo Kobelnik ◽

Yara Barbosa Franco ◽

Fernando Luiz Lavoie ◽

Jefferson Lins da Silva ◽

...

Keyword(s):

Uv Light ◽

Polymeric Materials ◽

Tensile Tests ◽

Thermomechanical Analysis ◽

Material Stiffness ◽

Before And After ◽

Electron Microscopy Analysis ◽

Physical Tests ◽

Nonwoven Geotextile

The use of polymeric materials such as geosynthetics in infrastructure works has been increasing over the last decades, as they bring down costs and provide long-term benefits. However, the aging of polymers raises the question of its long-term durability and for this reason researchers have been studying a sort of techniques to search for the required renewal time. This paper examined a commercial polypropylene (PP) nonwoven geotextile before and after 500 h and 1000 h exposure to ultraviolet (UV) light by performing laboratory accelerated ultraviolet-aging tests. The state of the polymeric material after UV exposure was studied through a wide set of tests, including mechanical and physical tests and thermoanalytical tests and scanning electron microscopy analysis. The calorimetric evaluations (DSC) showed distinct behaviors in sample melting points, attributed to the UV radiation effect on the aged samples. Furthermore, after exposure, the samples presented low thermal stability in the thermomechanical analysis (TMA), with a continuing decrease in their thicknesses. The tensile tests showed an increase in material stiffness after exposition. This study demonstrates that UV aging has effects on the properties of the polypropylene polymer.

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Finite Element Method modeling of Additive Manufactured Compressor Wheel

Journal of The Institution of Engineers (India) Series D ◽

10.1007/s40033-021-00251-8 ◽

2021 ◽

Author(s):

Márton Tamás Birosz ◽

Mátyás Andó ◽

Sudhanraj Jeganmohan

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Finite Element Method Simulation ◽

Element Model ◽

Tensile Tests ◽

Raw Material ◽

Isotropic Hardening ◽

Compressor Wheel ◽

Material Extrusion ◽

Element Method

AbstractDesigning components is a complex task, which depends on the component function, the raw material, and the production technology. In the case of rotating parts with higher RPM, the creep and orientation are essential material properties. The PLA components made with the material extrusion process are more resistant than VeroWhite (material jetting) and behave similarly to weakly cross-linked elastomers. Also, based on the tensile tests, Young’s modulus shows minimal anisotropy. Multilinear isotropic hardening and modified time hardening models are used to create the finite element model. Based on the measurements, the finite element method simulation was identified. The deformation in the compressor wheel during rotation became definable. It was concluded that the strain of the compressor wheel manufactured with material extrusion technology is not significant.

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