Ultimate strength prediction of two-dimensional tri-axial braided composites based on an analytical laminate model

2018 ◽  
Vol 37 (13) ◽  
pp. 917-929 ◽  
Author(s):  
Min Jing ◽  
Jian Wu ◽  
Yaqiong Deng ◽  
Wei Ye ◽  
Huiming Ning ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Failure Analysis ◽  
Ultimate Strength ◽  
Present Model ◽  
Strength Prediction ◽  
Two Dimensional ◽  
Braided Composites ◽  
Surrounding Matrix ◽  
Unidirectional Fibers ◽  
Series Of Experiments

An analytical laminate model was newly proposed to predict the ultimate strengths of two-dimensional tri-axial braided composites under in-plane loadings. The composite was modeled as a laminate possessing four plies. Among these four plies, there were three plies consisting of unidirectional fibers along with surrounding matrix and one ply containing only matrix. A progressive ply failure analysis was performed. A series of experiments were conducted. The present model was verified experimentally by using our and other researchers’ data. Moreover, we compared this model’s results with the numerical ones obtained by us. The results show that the present model has the potential to predict the effective elastic properties and ultimate strengths of two-dimensional tri-axial braided composites. Finally, the effect of the braid angle on the mechanical properties of a two-dimensional tri-axial braided composite was explored based on the mentioned model.

scholarly journals Effect of Angle, Temperature and Vacancy Defects on Mechanical Properties of PSI-Graphene

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 238 ◽  
Author(s):  
Lu Xie ◽  
Tingwei Sun ◽  
Chenwei He ◽  
Haojie An ◽  
Qin Qin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Ultimate Strength ◽  
Fracture Morphology ◽  
Dynamics Simulation ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Carbon Allotrope ◽  
Vacancy Defects ◽  
Carbon Structures

The PSI-graphene, a two-dimensional structure, was a novel carbon allotrope. In this paper, based on molecular dynamics simulation, the effects of stretching direction, temperature and vacancy defects on the mechanical properties of PSI-graphene were studied. We found that when PSI-graphene was stretched along 0° and 90° at 300 K, the ultimate strength reached a maximum of about 65 GPa. And when stretched along 54.2° and 155.2° at 300 K, the Young’s modulus had peaks, which were 1105 GPa and 2082 GPa, respectively. In addition, when the temperature was raised from 300 K to 900 K, the ultimate strength in all directions was reduced. The fracture morphology of PSI-graphene stretched at different angles was also shown in the text. In addition, the number of points removed from PSI-graphene sheet also seriously affected the tensile properties of the material. It was found that, compared with graphene, PSI-graphene didn’t have the negative Poisson’s ratio phenomenon when it was stretched along the direction of 0°, 11.2°, 24.8° and 34.7°. Our results provided a reference for studying the multi-angle stretching of other carbon structures at various temperatures.

A Novel Junction Profiling Methodology

2010 ◽  
Author(s):  
Tomokazu Nakai
Keyword(s):  
Failure Analysis ◽  
Profile Analysis ◽  
Semiconductor Devices ◽  
Wet Etching ◽  
Two Dimensional ◽  
Electrical Characteristics ◽  
Conventional Methods

Abstract Currently many methods are available to obtain a junction profile of semiconductor devices, but the conventional methods have drawbacks, and they could be obstacles for junction profile analysis. This paper introduces an anodic wet etching-based two-dimensional junction profiling method, which is practical, efficient, and reliable for failure analysis and electrical characteristics evaluation.

scholarly journals Performance of SCAN Meta-GGA Functionals on Nonlinear Mechanics of Graphene-Like g-SiC

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 120
Author(s):  
Qing Peng
Keyword(s):  
Mechanical Properties ◽  
Density Functional ◽  
Large Strains ◽  
Two Dimensional ◽  
Nonlinear Mechanics ◽  
Generalized Gradient ◽  
Mechanics Of Materials ◽  
Nonlinear Mechanical ◽  
Direct Band ◽  
Simulations And Modeling

Although meta-generalized-gradient approximations (meta-GGAs) are believed potentially the most accurate among the efficient first-principles calculations, the performance has not been accessed on the nonlinear mechanical properties of two-dimensional nanomaterials. Graphene, like two-dimensional silicon carbide g-SiC, has a wide direct band-gap with applications in high-power electronics and solar energy. Taken g-SiC as a paradigm, we have investigated the performance of meta-GGA functionals on the nonlinear mechanical properties under large strains, both compressive and tensile, along three deformation modes using Strongly Constrained and Appropriately Normed Semilocal Density Functional (SCAN) as an example. A close comparison suggests that the nonlinear mechanics predicted from SCAN are very similar to that of Perdew-Burke-Ernzerhof (PBE) formulated functional, a standard Density Functional Theory (DFT) functional. The improvement from SCAN calculation over PBE calculation is minor, despite the considerable increase of computing demand. This study could be helpful in selection of density functionals in simulations and modeling of mechanics of materials.

Determination of mechanical properties of two-phase and hybrid nanocomposites: experimental determination and multiscale modeling

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud Haghighi ◽  
Hossein Golestanian ◽  
Farshid Aghadavoudi
Keyword(s):  
Mechanical Properties ◽  
Ultimate Strength ◽  
Multiscale Modeling ◽  
Filler Content ◽  
Hybrid Nanocomposites ◽  
Dynamics Simulation ◽  
Strength Increase ◽  
Two Phase ◽  
Macro Scale ◽  
Elongation To Failure

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.

Monitoring the Travel Characteristics of High Voltage Circuit Breaker Based on TLD

2014 ◽  
Vol 687-691 ◽  
pp. 938-941
Author(s):  
Bao Shu Li ◽  
Shang Chen ◽  
Xian Ping Zhao ◽  
Wei Hua Niu
Keyword(s):  
Mechanical Properties ◽  
Circuit Breaker ◽  
Travel Speed ◽  
Video Tracking ◽  
Two Dimensional ◽  
High Voltage Circuit Breaker ◽  
Vacuum Circuit Breaker ◽  
Tracking Technology ◽  
Methods Of Measurement ◽  
Speed Characteristic

For the circuit breaker, mechanical fault make up the largest share of the fault. In order to ensure reliable and secure power system can run,it is necessary to monitor the mechanical properties of the circuit breaker,which includes monitoring the breaker trip.By TLD video tracking technology ZN65-12 vacuum circuit breaker mechanical properties were measured,obtain a two-dimensional direction of travel, speed characteristic curves.The experimental results show that the error of the method used to obtain a circuit breaker stroke, speed and other parameters of not more than 1mm,compared with traditional methods of measurement can get richer information.

Strength Prediction of Laminated Composites upon Independent Constituent Properties

2015 ◽  
Vol 665 ◽  
pp. 153-156
Author(s):  
Zheng Ming Huang ◽  
Li Min Xin
Keyword(s):  
Ultimate Strength ◽  
Input Data ◽  
Laminated Composites ◽  
Laminated Composite ◽  
Failure Detection ◽  
Strength Prediction ◽  
Internal Stresses ◽  
Matrix Properties

To predict ultimate strength of a laminated composite subjected to any load only using its constituent fiber and matrix properties measured independently, three challenging problems must be resolved with high success. First, internal stresses in the fiber and matrix must be accurately determined. Second, efficient failure detection for laminae and laminate upon the internal stresses must be achieved. Last but not the least, input data for the in-situ strengths of the constituents must be defined correctly from their original counterparts, as the former, different from the latter, are immeasurable. This presentation briefly summarizes our work on the targeted subject. All of the three issues have been systematically addressed with reasonable success.

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