scholarly journals Damage and failure modelling of hybrid three-dimensional textile composites: a mesh objective multi-scale approach

2016 ◽  
Vol 374 (2071) ◽  
pp. 20160036 ◽  
Author(s):  
Deepak K. Patel ◽  
Anthony M. Waas
Keyword(s):  
Structural Dynamics ◽  
Three Dimensional ◽  
Textile Composites ◽  
Unit Cell ◽  
Progressive Damage ◽  
Concentric Cylinder ◽  
Geometric Imperfections ◽  
Damage And Failure ◽  
Multi Scale ◽  
The Matrix

This paper is concerned with predicting the progressive damage and failure of multi-layered hybrid textile composites subjected to uniaxial tensile loading, using a novel two-scale computational mechanics framework. These composites include three-dimensional woven textile composites (3DWTCs) with glass, carbon and Kevlar fibre tows. Progressive damage and failure of 3DWTCs at different length scales are captured in the present model by using a macroscale finite-element (FE) analysis at the representative unit cell (RUC) level, while a closed-form micromechanics analysis is implemented simultaneously at the subscale level using material properties of the constituents (fibre and matrix) as input. The N -layers concentric cylinder (NCYL) model (Zhang and Waas 2014 Acta Mech. 225 , 1391–1417; Patel et al. submitted Acta Mech. ) to compute local stress, srain and displacement fields in the fibre and matrix is used at the subscale. The 2-CYL fibre–matrix concentric cylinder model is extended to fibre and ( N −1) matrix layers, keeping the volume fraction constant, and hence is called the NCYL model where the matrix damage can be captured locally within each discrete layer of the matrix volume. The influence of matrix microdamage at the subscale causes progressive degradation of fibre tow stiffness and matrix stiffness at the macroscale. The global RUC stiffness matrix remains positive definite, until the strain softening response resulting from different failure modes (such as fibre tow breakage, tow splitting in the transverse direction due to matrix cracking inside tow and surrounding matrix tensile failure outside of fibre tows) are initiated. At this stage, the macroscopic post-peak softening response is modelled using the mesh objective smeared crack approach (Rots et al. 1985 HERON 30 , 1–48; Heinrich and Waas 2012 53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Honolulu, HI, 23–26 April 2012 . AIAA 2012-1537). Manufacturing-induced geometric imperfections are included in the simulation, where the FE mesh of the unit cell is generated directly from micro-computed tomography (MCT) real data using a code S impleware . Results from multi-scale analysis for both an idealized perfect geometry and one that includes geometric imperfections are compared with experimental results (Pankow et al. 2012 53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Honolulu, HI, 23–26 April 2012 . AIAA 2012-1572). This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

Advanced three-dimensional electromagnetic modeling using a nested integral equation approach

2021 ◽  
Author(s):  
Chaojian Chen ◽  
Mikhail Kruglyakov ◽  
Alexey Kuvshinov
Keyword(s):  
Integral Equation ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Electromagnetic Modeling ◽  
Multi Scale ◽  
Scale Modeling ◽  
Uniform Grids ◽  
The Matrix ◽  
Integral Equation Approach ◽  
Matrix Vector

Summary Most of the existing three-dimensional (3-D) electromagnetic (EM) modeling solvers based on the integral equation (IE) method exploit fast Fourier transform (FFT) to accelerate the matrix-vector multiplications. This in turn requires a laterally-uniform discretization of the modeling domain. However, there is often a need for multi-scale modeling and inversion, for instance, to properly account for the effects of non-uniform distant structures, and at the same time, to accurately model the effects from local anomalies. In such scenarios, the usage of laterally-uniform grids leads to excessive computational loads, both in terms of memory and time. To alleviate this problem, we developed an efficient 3-D EM modeling tool based on a multi-nested IE approach. Within this approach, the IE modeling is first performed at a large domain and on a (laterally-uniform) coarse grid, and then the results are refined in the region of interest by performing modeling at a smaller domain and on a (laterally-uniform) denser grid. At the latter stage, the modeling results obtained at the previous stage are exploited. The lateral uniformity of the grids at each stage allows us to keep using the FFT for the matrix-vector multiplications. An important novelty of the paper is a development of a “rim domain” concept which further improves the performance of the multi-nested IE approach. We verify the developed tool on both idealized and realistic 3-D conductivity models, and demonstrate its efficiency and accuracy.

scholarly journals Determining the Damage and Failure Behaviour of Textile Reinforced Composites under Combined In-Plane and Out-of-Plane Loading

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4772
Author(s):  
Christian Düreth ◽  
Daniel Weck ◽  
Robert Böhm ◽  
Mike Thieme ◽  
Maik Gude ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Fibre Volume ◽  
Reinforced Composites ◽  
Biaxial Testing ◽  
Damage And Failure ◽  
Multi Scale ◽  
Load Paths ◽  
Biaxial Load ◽  
Out Of Plane ◽  
Ct Data

The absence of sufficient knowledge of the heterogeneous damage behaviour of textile reinforced composites, especially under combined in-plane and out-of-plane loadings, requires the development of multi-scale experimental and numerical methods. In the scope of this paper, three different types of plain weave fabrics with increasing areal weight were considered to characterise the influence of ondulation and nesting effects on the damage behaviour. Therefore an advanced new biaxial testing method has been elaborated to experimentally determine the fracture resistance at the combined biaxial loads. Methods in image processing of the acquired in-situ CT data and micrographs have been utilised to obtain profound knowledge of the textile geometry and the distribution of the fibre volume content of each type. Combining the derived data of the idealised geometry with a numerical multi-scale approach was sufficient to determine the fracture resistances of predefined uniaxial and biaxial load paths. Thereby, Cuntze’s three-dimensional failure mode concept was incorporated to predict damage and failure. The embedded element method was used to obtain a structured mesh of the complex textile geometries. The usage of statistical and visualisation methods contributed to a profound comprehension of the ondulation and nesting effects.

Effect of Assumed Tow Architecture on Predicted Moduli and Stresses in Plain Weave Composites

1995 ◽  
Vol 29 (16) ◽  
pp. 2134-2159 ◽  
Author(s):  
Clinton Chapman ◽  
John Whitcomb
Keyword(s):  
Finite Elements ◽  
Cross Section ◽  
Transverse Shear ◽  
Material Properties ◽  
Three Dimensional ◽  
Textile Composites ◽  
Unit Cell ◽  
Accurate Prediction ◽  
Constant Cross Section ◽  
Plain Weave

This paper examines the effect of assumed tow architecture on the predicted moduli and stresses in plain weave textile composites. In particular, the effect of how a constant cross-section is assumed to sweep-out the volume of a tow is explored. Two architectures are examined which have a sinusoidal tow path and a lenticular cross-section. Three-dimensional finite elements are employed to model a T300/Epoxy plain weave composite with symmetrically stacked mats. Macroscopically homogeneous in-plane extension and shear and transverse shear loadings were considered. Symmetries are exploited which permitted modeling of only 1/32nd of the unit cell. Accounting for the variation of material properties throughout each element is determined to be necessary for accurate prediction of stresses in the composite. For low waviness, the two tow architectures examined are very similar. At high waviness, the stress predictions are much more sensitive to the assumed tow geometry.

Progressive damage modelling and experimental investigation of three-dimensional orthogonal woven composites with tilted binder

2019 ◽  
Vol 50 (1) ◽  
pp. 70-97 ◽  
Author(s):  
Wei Tao ◽  
Ping Zhu ◽  
Di Wang ◽  
Changhu Zhao ◽  
Zhao Liu
Keyword(s):  
Carbon Fiber ◽  
Three Dimensional ◽  
Fiber Composites ◽  
Unit Cell ◽  
Matrix Cracking ◽  
Woven Composites ◽  
Carbon Fiber Composites ◽  
Progressive Damage ◽  
Damage Initiation ◽  
3D Orthogonal Woven

This paper investigates the tensile properties of 3D orthogonal woven carbon fiber composites with tilted binder by experiment and simulation. The tensile failure strain and fracture mode of this composite show distinguished discrepancy with idealized 3D orthogonal woven composites experimentally. In order to explain this specific failure mechanism, a unit cell finite element model incorporated with damage models of constituents is established to reproduce the damage initiation and propagation of 3D orthogonal woven composites with tilted binder during tensile test. A three-dimensional failure criterion based on Hashin's criterion and Pinho's criterion is utilized to describe the progressive damage of yarns, while the non-linear behavior of the matrix is predicted by Drucker-Prager yield criterion. Besides, a traction-separation law is applied to predict the damage of yarn-matrix interface. The proposed unit cell model is correlated and validated by global stress–strain curves, DIC full-field strain distributions and modulus history curve. The damage evolution process of 3D orthogonal woven carbon fiber composites with tilted binder, including fiber tow failure, matrix cracking, and interfacial debonding, is recorded and investigated by the modulus history curve from simulation.

Development for CANDU-6 Moderator Temperature Prediction by Using Porous Media Approach

2012 ◽  
Author(s):  
Jae Ryong Lee ◽  
Han Young Yoon ◽  
Hyoung Tae Kim ◽  
Jae Jun Jeong
Keyword(s):  
Porous Media ◽  
Three Dimensional ◽  
Axial Flow ◽  
Physical Models ◽  
Thermal Hydraulics ◽  
Two Phase ◽  
Grid Systems ◽  
Multi Scale ◽  
The Matrix ◽  
Calculation Results

In this study, a thermal hydraulic behavior of the moderator in the CANDU reactor was numerically investigated by using CUPID code. KAERI has been developing a component-scale thermal hydraulics code, CUPID. The aim of the code is multi-dimensional, multi-physics and multi-scale thermal hydraulics analysis. This code adopts a three-dimensional, transient, two-phase and three-field model, and includes physical models and correlations of the interfacial mass, momentum, and energy transfer for the closure. To avoid the complexity to generate computational geometry around the matrix of 440 Calandria tubes, a porous media approach was applied. Flow resistance inside the porous media zone was derived from the empirical correlation of the frictional pressure loss. In order to consider the turbulent jet inflows from the inlet nozzles, the standard k-ε turbulence model was applied. For the grid dependency test, three different grid systems were tested. The moderator test vessel at Stern Laboratories Inc. (SLI) for the validation is a cylinder with a diameter of 2m and a length of 0.2m (a thin “slice” of CANDU-6 Calandria vessel). Since the axial flow is assumed to be invariant, two-dimensional calculation was performed. Vertical profile of the liquid temperature was compared with other calculation results as well as experimental data.

scholarly journals Progressive Failure Simulation of Notched Tensile Specimen for Triaxially-Braided Composites

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 833 ◽  
Author(s):  
Zhenqiang Zhao ◽  
Haoyuan Dang ◽  
Jun Xing ◽  
Xi Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Textile Composites ◽  
Fiber Bundles ◽  
Progressive Damage ◽  
Interfacial Damage ◽  
Braided Composites ◽  
Internal Damage ◽  
Notched Specimen ◽  
Damage Behavior ◽  
Damage Initiation

The mechanical characterization of textile composites is a challenging task, due to their nonuniform deformation and complicated failure phenomena. This article introduces a three-dimensional mesoscale finite element model to investigate the progressive damage behavior of a notched single-layer triaxially-braided composite subjected to axial tension. The damage initiation and propagation in fiber bundles are simulated using three-dimensional failure criteria and damage evolution law. A traction–separation law has been applied to predict the interfacial damage of fiber bundles. The proposed model is correlated and validated by the experimentally measured full field strain distributions and effective strength of the notched specimen. The progressive damage behavior of the fiber bundles is studied by examining the damage and stress contours at different loading stages. Parametric numerical studies are conducted to explore the role of modeling parameters and geometric characteristics on the internal damage behavior and global measured properties of the notched specimen. Moreover, the correlations of damage behavior, global stress–strain response, and the efficiency of the notched specimen are discussed in detail. The results of this paper deliver a throughout understanding of the damage behavior of braided composites and can help the specimen design of textile composites.

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