Modeling and Simulation of 3-D Interfacial Cracks by XFEM

2017 ◽  
Author(s):  
Himanshu Pathak ◽  
Akhilendra Singh ◽  
Indra Vir Singh ◽  
Sunny Zafar
Keyword(s):  
Mechanical Properties ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Interfacial Crack ◽  
Partition Of Unity ◽  
Integral Approach ◽  
Cylindrical Domain ◽  
Material Interface ◽  
Interfacial Cracks ◽  
Heaviside Enrichment

The structural integrity of multi-layered material depends on the mechanical properties and the fracture behaviour at the interface. The sudden jump in mechanical properties across the interface is the major source of failure in layered materials. An accurate evaluation of mixed-mode SIFs becomes essential for safe design of layered structure components. In this work, extended finite element method (XFEM) has been used to analyze interfacial cracked three-dimensional structures under mechanical loading. In XFEM, partition of unity enrichment concept is used to model a crack e.g. a crack surface is modeled by Heaviside enrichment function whereas a crack front is modeled by branch enrichment functions. Discontinuity due the presence of bi-material interface is modeled by the signed distance function. Modified domain based interaction integral approach has been used to evaluate the individual stress intensity factors. Three-dimensional cylindrical domain having an interfacial crack is taken for the simulations. A comparative analysis has been performed with and without an interface for an embedded penny shape crack. The effect of material interface on the SIFs has been analyzed in detail. Finally, a three-dimensional interfacial crack growth simulation has been performed for arbitrary shape crack.

Composite Patch Repair of Structural Member by Coupled FE-EFG Approach

2016 ◽  
Vol 829 ◽  
pp. 78-82
Author(s):  
Himanshu Pathak ◽  
Akhilendra Singh ◽  
Indra Vir Singh
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Partition Of Unity ◽  
Patch Repair ◽  
Integral Approach ◽  
Fe Method ◽  
Material Interface ◽  
Composite Patch ◽  
Geometric Discontinuities ◽  
Element Free

This paper presents a simple and efficient coupled finite element-element free Galekrin (FE-EFG) approach to simulate three-dimensional composite patch repair problem. In coupled FE-EFG approach, extended element free Galerkin (XEFG) is used near the crack surface as it can accurately model the discontinuities while the rest of domain is approximated by standard finite element (FE) method. The transition between FE and XEFG was modelled by a ramp function. The geometric discontinuities like crack and material interface are modeled by adding enrichment functions in EFG displacement approximation through partition of unity (PU). The location of geometrical discontinuity is traced by vector level set method. A domain based J-integral approach is used for the evaluation of stress intensity factors.

scholarly journals Mechanics Of Interfacial Crack Propagation In Microscratching

1996 ◽  
Vol 436 ◽  
Author(s):  
Maarten P. de Boer ◽  
John C. Nelson ◽  
William W. Gerberich
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Grain Boundary ◽  
Interfacial Crack ◽  
Strain Energy Release ◽  
Linear Elastic ◽  
Interfacial Cracks ◽  
Bending Strain ◽  
Diamond Indenter ◽  
Boundary Fracture

AbstractA new probing technique has been developed to test thin film mechanical properties. In the Microwedge Scratch Test (MWST), a wedge shaped diamond indenter tip is drawn along a fine line, while simultaneously being driven into the line. We compare microwedge scratching of Zone 1 and Zone T thin film specimens of sputtered W on SiO2. Symptomatic of its poor mechanical properties, the Zone 1 film displays three separate crack systems. Because of its superior grain boundary strength, the Zone T film displayed only one of these - an interfacial crack system. Using bimaterial linear elastic fracture mechanics, governing equations are developed for propagating interfacial cracks, including expressions for strain energy release rate, bending strain, and mode mixity. Grain boundary fracture strength information may be deduced from the Zone 1 films, while adhesion may be inferred from the Zone T films.

Stress Intensity Factor for Interfacial Cracks in Bi-Materials Using Incompatible Numerical Manifold Method

2011 ◽  
Vol 327 ◽  
pp. 109-114
Author(s):  
Gao Feng Wei ◽  
Hong Fen Gao ◽  
Hai Hui Jiang
Keyword(s):  
Stress Intensity ◽  
Interfacial Crack ◽  
Partition Of Unity ◽  
Complex Stress ◽  
Element Approximation ◽  
Numerical Manifold Method ◽  
Displacement Fields ◽  
Interfacial Cracks ◽  
Crack Problems ◽  
Numerical Manifold

Incompatible numerical manifold method (INMM) uses interpolation functions based on the concept of partition of unity, and considers the asymptotic solution and the discontinuity of displacement. This paper describes the application of INMM to bi-material interfacial crack. The two dimensional near-tip asymptotic displacement functions are added to the trial function approximation. This enables the domain to be modeled by manifold elements without explicitly meshing the crack surfaces. The crack-tip enrichment functions are chosen as those that span the asymptotic displacement fields for an interfacial crack. The INMM facilitates the incorporation of the oscillatory nature of the singularity within a conforming manifold element approximation. The complex stress intensity factors for bi-material interfacial cracks are numerically evaluated. Good agreement between the numerical results and the analytical solutions for benchmark interfacial crack problems is realized.

scholarly journals 3D-Printed Oral Dosage Forms: Mechanical Properties, Computational Approaches and Applications

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1401
Author(s):  
Danae Karalia ◽  
Angeliki Siamidi ◽  
Vangelis Karalis ◽  
Marilena Vlachou
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Computational Methods ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Drug Distribution ◽  
Dosage Forms ◽  
Oral Dosage ◽  
3D Printed ◽  
Oral Dosage Forms

The aim of this review is to present the factors influencing the mechanical properties of 3D-printed oral dosage forms. It also explores how it is possible to use specific excipients and printing parameters to maintain the structural integrity of printed drug products while meeting the needs of patients. Three-dimensional (3D) printing is an emerging manufacturing technology that is gaining acceptance in the pharmaceutical industry to overcome traditional mass production and move toward personalized pharmacotherapy. After continuous research over the last thirty years, 3D printing now offers numerous opportunities to personalize oral dosage forms in terms of size, shape, release profile, or dose modification. However, there is still a long way to go before 3D printing is integrated into clinical practice. 3D printing techniques follow a different process than traditional oral dosage from manufacturing methods. Currently, there are no specific guidelines for the hardness and friability of 3D printed solid oral dosage forms. Therefore, new regulatory frameworks for 3D-printed oral dosage forms should be established to ensure that they meet all appropriate quality standards. The evaluation of mechanical properties of solid dosage forms is an integral part of quality control, as tablets must withstand mechanical stresses during manufacturing processes, transportation, and drug distribution as well as rough handling by the end user. Until now, this has been achieved through extensive pre- and post-processing testing, which is often time-consuming. However, computational methods combined with 3D printing technology can open up a new avenue for the design and construction of 3D tablets, enabling the fabrication of structures with complex microstructures and desired mechanical properties. In this context, the emerging role of computational methods and artificial intelligence techniques is highlighted.

Numerical Analysis of Three-Dimensional Semi-Elliptical Interfacial Cracks Subjected to Indentation Load

2014 ◽  
Vol 627 ◽  
pp. 289-292 ◽  
Author(s):  
N. Kurihara ◽  
Masayuki Arai
Keyword(s):  
Fracture Toughness ◽  
Three Dimensional ◽  
Analytical Formula ◽  
Interfacial Crack ◽  
Indentation Test ◽  
Interfacial Fracture ◽  
Indentation Load ◽  
J Integral ◽  
Interfacial Fracture Toughness ◽  
Interfacial Cracks

The aim of this study is to show elastic J-integral needed to evaluate the interfacial fracture toughness of bi-material in indentation test. Three dimensional J-integrals along the crack front tip in semi-elliptical crack lying on the interface were analyzed using domain integral technique installed in commercialized finite element code MARC. The J-integral was calculated under several kind of aspect ratio of semi-elliptical cracks. In order to have to evaluate the interfacial fracture toughness from interfacial crack length and indentation load obtained in indentation tests, the analytical formula for two dimensional interfacial crack J-integral under plane stress, which had been introduced by J. R. Rice and G. C. Sih, was modified in reflecting upon the three dimensional effect. Finally, the indentation test was conducted for Aluminum alloy/ PMMA combination sample, and the associated fracture toughness was evaluated.Fig.1 Schematic illustration of indentation testFig.2 Schematic illustration of analysis mode

Investigation of three-dimensional moisture diffusion modeling and mechanical degradation of carbon/bismaleimide composites under seawater conditioning

2017 ◽  
Vol 52 (10) ◽  
pp. 1339-1351 ◽  
Author(s):  
Z Huo ◽  
S Anandan ◽  
M Xu ◽  
K Chandrashekhara
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Three Dimensional ◽  
Moisture Diffusion ◽  
Element Model ◽  
Mechanical Degradation ◽  
Interfacial Cracks ◽  
Beam Shear ◽  
Interlaminar Shear ◽  
Out Of Autoclave

The effect of moisture diffusion on the mechanical properties of carbon/bismaleimide composites exposed to seawater conditioning at elevated temperatures was investigated in this study. Carbon/bismaleimide composites with two stacking sequences (unidirectional and cross-ply) were fabricated using out-of-autoclave process. Testing coupons were immersed in the seawater at two elevated temperatures (50℃ and 90℃) for approximately 3 months. Moisture diffusivities and solubility for each type of carbon/bismaleimide specimen were characterized using the experimental data. A three-dimensional dynamic finite element model was developed using these parameters to predict the moisture diffusion behavior in the carbon/bismaleimide laminates. The degradation of mechanical properties due to hygrothermal aging was assessed by short-beam shear and three-point bending tests. It was found that flexural strength and interlaminar shear strength reductions are higher at 90℃ aging than that at 50℃ aging. The reduction in mechanical properties for bismaleimide laminates can be attributed to the fiber/matrix interfacial cracks observed by scanning electron microscopy.

Biotemplated facile synthesis of three‐dimensional micro/nanoporous tin oxide: improving the flammable and mechanical properties of flexible PVC

2019 ◽  
Vol 14 (8) ◽  
pp. 828-830 ◽  
Author(s):  
Weihua Meng ◽  
Weihong Wu ◽  
Weiwei Zhang ◽  
Luyao Cheng ◽  
Yunhong Jiao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tin Oxide ◽  
Three Dimensional ◽  
Facile Synthesis

scholarly journals Is Dialdehyde Chitosan a Good Substance to Modify Physicochemical Properties of Biopolymeric Materials?

2021 ◽  
Vol 22 (7) ◽  
pp. 3391
Author(s):  
Sylwia Grabska-Zielińska ◽  
Alina Sionkowska ◽  
Ewa Olewnik-Kruszkowska ◽  
Katarzyna Reczyńska ◽  
Elżbieta Pamuła
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Physicochemical Properties ◽  
Silk Fibroin ◽  
Three Dimensional ◽  
Microscopy Imaging ◽  
Maximum Deformation ◽  
One Step ◽  
Chitosan Blends ◽  
Fourier Transfer Infrared Spectroscopy

The aim of this work was to compare physicochemical properties of three dimensional scaffolds based on silk fibroin, collagen and chitosan blends, cross-linked with dialdehyde starch (DAS) and dialdehyde chitosan (DAC). DAS was commercially available, while DAC was obtained by one-step synthesis. Structure and physicochemical properties of the materials were characterized using Fourier transfer infrared spectroscopy with attenuated total reflectance device (FTIR-ATR), swelling behavior and water content measurements, porosity and density observations, scanning electron microscopy imaging (SEM), mechanical properties evaluation and thermogravimetric analysis. Metabolic activity with AlamarBlue assay and live/dead fluorescence staining were performed to evaluate the cytocompatibility of the obtained materials with MG-63 osteoblast-like cells. The results showed that the properties of the scaffolds based on silk fibroin, collagen and chitosan can be modified by chemical cross-linking with DAS and DAC. It was found that DAS and DAC have different influence on the properties of biopolymeric scaffolds. Materials cross-linked with DAS were characterized by higher swelling ability (~4000% for DAS cross-linked materials; ~2500% for DAC cross-linked materials), they had lower density (Coll/CTS/30SF scaffold cross-linked with DAS: 21.8 ± 2.4 g/cm3; cross-linked with DAC: 14.6 ± 0.7 g/cm3) and lower mechanical properties (maximum deformation for DAC cross-linked scaffolds was about 69%; for DAS cross-linked scaffolds it was in the range of 12.67 ± 1.51% and 19.83 ± 1.30%) in comparison to materials cross-linked with DAC. Additionally, scaffolds cross-linked with DAS exhibited higher biocompatibility than those cross-linked with DAC. However, the obtained results showed that both types of scaffolds can provide the support required in regenerative medicine and tissue engineering. The scaffolds presented in the present work can be potentially used in bone tissue engineering to facilitate healing of small bone defects.

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