scholarly journals Computing the effective crack energy of heterogeneous and anisotropic microstructures via anisotropic minimal surfaces

Author(s):  
Felix Ernesti ◽  
Matti Schneider

AbstractA variety of materials, such as polycrystalline ceramics or carbon fiber reinforced polymers, show a pronounced anisotropy in their local crack resistance. We introduce an FFT-based method to compute the effective crack energy of heterogeneous, locally anisotropic materials. Recent theoretical works ensure the existence of representative volume elements for fracture mechanics described by the Francfort–Marigo model. Based on these formulae, FFT-based algorithms for computing the effective crack energy of random heterogeneous media were proposed, and subsequently improved in terms of discretization and solution methods. In this work, we propose a maximum-flow solver for computing the effective crack energy of heterogeneous materials with local anisotropy in the material parameters. We apply this method to polycrystalline ceramics with an intergranular weak plane and fiber structures with transversely isotropic crack resistance.

2021 ◽  
Vol 878 ◽  
pp. 127-133
Author(s):  
J. Selejdak ◽  
Y. Blikharskyy ◽  
R. Khmil ◽  
Z. Blikharskyy

This paper presents the experimental testing of eccentrically compressed reinforced concrete columns. There are experimental results of crack resistance of non-strengthened (control) and strengthened RC columns in the tension zone. The columns were strengthened by carbon fiber reinforced polymers (CFRP). As a result of experimental studies with the columns strengthened by CFRP, we obtain that the width of their crack decreased by an average of 33%. The eccentric compression load of the crack’s appearance increased from 40 kN to 60 kN for strengthened columns.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
H. A. Khawaja ◽  
T. A. Bertelsen ◽  
R. Andreassen ◽  
M. Moatamedi

The paper gives the study of the response of carbon fiber reinforced polymers (CRFP) quasi-isotropic shell structures under the influence of dynamic loading. The quasi-isotropic CRFP shell specimens are fabricated using Multipreg E720 laminates. These laminates are laid in such a way that shell structure has equal strength and mechanical properties in the two-dimensional (2D) plane and hence can be regarded as quasi-isotropic. In this study, the dynamic loading is generated using shock waves in a shock tube experimental setup. The strain and pressure data is collected from the experiments. Additional tests are carried out using Material Test System (MTS) for both tensile and flexural response of CRFP. Results obtained from experiments are compared with numerical simulations using ANSYS Multiphysics 14.0 finite element method (FEM) package. The numerical simulation and experimental results are found to be in good agreement.


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