Numerical Interlaminar Shear Damage Analysis of Fiber Reinforced Composites Improved by ZnO Nanowires

2020 ◽  
Author(s):  
Parisa Marashizadeh ◽  
Mohammad Abshirini ◽  
Mrinal Saha ◽  
Yingtao Liu
Keyword(s):  
Hybrid Composite ◽  
Zno Nanowires ◽  
Hybrid Structures ◽  
Scale Model ◽  
Damage Analysis ◽  
Fiber Reinforced ◽  
Micro Scale ◽  
Vertically Aligned ◽  
Interlaminar Shear ◽  
Meso Scale

Abstract In this study, the damage analysis of hybrid carbon fiber reinforced polymer (CFRP) composited with vertically aligned zinc oxide (ZnO) nanowires is investigated numerically. The effect of growing nanowires on improving the interlaminar shear strength (ILSS) of the hybrid structures is explored. The multi-scale model developed to make a bridge between the materials with different length scales available in the hybrid structures, including micro-scale, meso-scale, and macros-scale. The vertically aligned ZnO nanowires on the lamina and embedded in the epoxy matrix creates an enhancement layer. The effective material properties of this layer are evaluated at micro-scale by homogenization analysis. The cohesive zone method is employed in the meso-scale to explore the interfacial behavior and delamination (interlaminar damage) between the homogenized stacking layer and the CFRP lamina. Besides, the strain-based failure criterion is implemented at the macro-scale to investigate the progressive damage of fiber and matrix in CFRP plies. This analysis is programmed in user-defined subroutine linked to ABAQUS finite element software. The three-dimensional hybrid composite short beam in the three-point bending load is simulated in ABAQUS Explicit packager, and the ILSS is obtained. The damage behavior of hybrid composite is compared to the bare CFRP beam. The results indicate that aligning nanowires on the plies improves the performance of CFRP composites.

scholarly journals A Multi-Point Meso–Micro Downscaling Method Including Atmospheric Stratification

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1191
Author(s):  
Renko Buhr ◽  
Hassan Kassem ◽  
Gerald Steinfeld ◽  
Michael Alletto ◽  
Björn Witha ◽  
...  
Keyword(s):  
Wind Energy ◽  
Single Point ◽  
Scale Model ◽  
Cfd Modeling ◽  
Modeling Framework ◽  
Site Assessment ◽  
Micro Scale ◽  
Scale Models ◽  
Wind Climate ◽  
Meso Scale

In wind energy site assessment, one major challenge is to represent both the local characteristics as well as general representation of the wind climate on site. Micro-scale models (e.g., Reynolds-Averaged-Navier-Stokes (RANS)) excel in the former, while meso-scale models (e.g., Weather Research and Forecasting (WRF)) in the latter. This paper presents a fast approach for meso–micro downscaling to an industry-applicable computational fluid dynamics (CFD) modeling framework. The model independent postprocessing tool chain is applied using the New European Wind Atlas (NEWA) on the meso-scale and THETA on the micro-scale side. We adapt on a previously developed methodology and extend it using a micro-scale model including stratification. We compare a single- and multi-point downscaling in critical flow situations and proof the concept on long-term mast data at Rödeser Berg in central Germany. In the longterm analysis, in respect to the pure meso-scale results, the statistical bias can be reduced up to 45% with a single-point downscaling and up to 107% (overcorrection of 7%) with a multi-point downscaling. We conclude that single-point downscaling is vital to combine meso-scale wind climate and micro-scale accuracy. The multi-point downscaling is further capable to include wind shear or veer from the meso-scale model into the downscaled velocity field. This adds both, accuracy and robustness, by minimal computational cost. The new introduction of stratification in the micro-scale model provides a marginal difference for the selected stability conditions, but gives a prospect on handling stratification in wind energy site assessment for future applications.

scholarly journals Multi-scale atmospheric environment modelling for urban areas

2009 ◽  
Vol 3 (1) ◽  
pp. 53-57 ◽  
Author(s):  
A. A. Baklanov ◽  
R. B. Nuterman
Keyword(s):  
Urban Areas ◽  
Scale Effects ◽  
Urban Setting ◽  
Atmospheric Environment ◽  
Scale Model ◽  
Limited Area ◽  
Nested Models ◽  
Micro Scale ◽  
Multi Scale ◽  
Meso Scale

Abstract. Modern supercomputers allow realising multi-scale systems for assessment and forecasting of urban meteorology, air pollution and emergency preparedness and considering nesting with obstacle-resolved models. A multi-scale modelling system with downscaling from regional to city-scale with the Environment – HIgh Resolution Limited Area Model (Enviro-HIRLAM) and to micro-scale with the obstacle-resolved Micro-scale Model for Urban Environment (M2UE) is suggested and demonstrated. The M2UE validation results versus the Mock Urban Setting Trial (MUST) experiment indicate satisfactory quality of the model. Necessary conditions for the choice of nested models, building descriptions, areas and resolutions of nested models are analysed. Two-way nesting (up- and down-scaling), when scale effects both directions (from the meso-scale on the micro-scale and from the micro-scale on the meso-scale), is also discussed.

scholarly journals Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 491 ◽  
Author(s):  
Yaozhong Zhang ◽  
Rajib Mandal ◽  
Daniel C. Ratchford ◽  
Rebecca Anthony ◽  
Junghoon Yeom
Keyword(s):  
Charge Separation ◽  
Material Characterization ◽  
Zno Nanowires ◽  
Hybrid Nanostructures ◽  
Optical Measurements ◽  
Environmentally Benign ◽  
Hybrid Structures ◽  
Si Nanocrystals ◽  
Vertically Aligned

Numerous semiconductor-based hybrid nanostructures have been studied for improved photodegradation performance resulting from their broadband optical response and enhanced charge separation/transport characteristics. However, these hybrid structures often involve elements that are rare or toxic. Here, we present the synthesis and material characterization of hybrid nanostructures consisting of zinc oxide (ZnO) nanowires (NWs) and silicon nanocrystals (Si-NCs), both abundant and environmentally benign, and evaluate them for photodegradation performance under various illumination conditions. When incorporating Si-NCs into the vertically-aligned ZnO NWs immobilized on substrates, the resulting photocatalysts exhibited a narrowed band gap, i.e., more responsive to visible light, and enhanced charge separation at the interface, i.e., more reactive species produced for degradation. Consequently, the hybrid Si-NCs/ZnO-NWs displayed a superior photodegradability for methylene blue under UV and white light in comparison to the pristine ZnO NWs. Based on the optical measurements, we hypothesize the band structures of Si-NCs/ZnO-NWs and the potential mechanism for the improved photodegradability.

Computational Multi-Scale Modelling of Fiber-Reinforced Composite Materials

2019 ◽  
Vol 827 ◽  
pp. 263-268
Author(s):  
Tsivolas Eleftherios ◽  
Leonidas N. Gergidis ◽  
Alkiviadis S. Paipetis
Keyword(s):  
Inclusion Problem ◽  
Numerical Homogenization ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Micro Scale ◽  
Multi Scale ◽  
Reinforced Composite ◽  
The Matrix ◽  
Scale Modelling ◽  
Meso Scale

A cross-ply fiber-reinforced composite in uniaxial tension is modelled using a mesoscale and a micro-scale approach comparing the results from both the analyses. The use of multi-scale modelling gives directly the macroscopic constitutive behaviour of the structures based on its microscopically heterogeneous representative volume element (RVE). In the meso-scale approach the material of each layer is modelled as a homogeneous transversely isotropic material whose properties resulted from a numerical homogenization analysis. One of the main advantages of micro-scale modelling is the ability to simulate damage mechanisms such as matrix cracking, delaminations of the matrix-fiber interface and fibre-damage. In the first part of this study, analytical and numerical homogenization schemes are compared. RVEs of continuous fibre and short-fibre reinforced composites are created, homogenized numerically and compared with the widespread analytical scheme of Mori-Tanaka based on Eshelby’s solution of the single inclusion problem. In the second part, results’ comparison between the simulations of both scales is performed. In the meso-scale model stochasticity has been introduced, assigning interfacial strength following a normal distribution, in order to predict cracking initiation, propagation and saturation at the matrix material. The stresses at the crack tips are compared with the stress fields around the cracks from the micro-scale analysis and the results are in good agreement.

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