SMART (Separating, Morphing, Adaptive and Remeshing Technology) is a finite element based crack growth simulation framework[1] recently developed in the ANSYS Mechanical Solver. Crack representation is essential for FE based fracture and crack growth simulation. The ability to control the mesh and ensure mesh quality at remeshing are essential for robust and accurate crack growth prediction. In this paper several examples and benchmarks are presented to demonstrate the effectiveness and validity of the SMART framework for complex crack propagation simulation. We will then present the latest technological advancements in SMART development related to meshing control with special focus on meshing refinement and coarsening, and adaptive crack initiation.
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Themes: Advanced Computational Methods in Fracture
ADVANCED CRACK TIP FIELD QUANTIFICATION USING DIGITAL IMAGE CORRELATION, MACHINE LEARNING, AND INTEGRAL EVALUATION [Keynote]
We use higher-order Williams coefficients from full-field displacement data obtained by digital image
correlation (DIC) to approximate complex crack tip fields with simpler expressions. The methodology is
based on invariant path integrals and machine-learned crack detection. We demonstrate the framework for
fatigue crack growth experiments of aluminium alloys and compare the results to matching finite element
simulations.
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AN AUTOMATED PROCESS FOR SOLVING DUCTILE DAMAGE PARAMETER SELECTION USING MACHINE LEARNING AND FINITE ELEMENT ANALYSIS
In this work we show how a machine learning algorithm based on a Bayesian optimization framework can be used in conjunction with finite element analysis to autonomously select parameter values for a ductile damage model representative of experimental test data.
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SINGULAR INTEGRAL EQUATION FOR SOLVING COHESIVE CRACK PROBLEM FOR INITIALLY RIGID TRACTION-SEPARATION RELATION
In case of an initially rigid traction-separation cohesive relation, the total potential energy is not differentiable. This makes the use of variational operator over it questionable. Therefore, the accurate application of FEM is mathematically doubtful. The present work bypasses this issue by modelling the cohesive crack problem as a singular integral equation and solving it using Chebyshev polynomials.
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REDEFINED J-INTEGRAL AND J-INTEGRAL RANGE DELTA-J AS FINITE STRAIN ELASTIC-PLASTIC CRACK PARAMETERS [Keynote]
The summary of applications of redefined three-dimensional J-integral and J-integral range Delta-J are presented in this paper. The redefined fracture parameters were derived with a rigorous consideration on energy dissipation into a small volume in the vicinity of the crack front. It can be seen as a rigorous extension of two-dimensional T_ε^*-integral to three-dimensional problem. The equation formulations are briefly presented in this paper. Then, their applications will be presented in the conference.
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THE VIRTUAL ELEMENT METHOD FOR EFFICIENT CRACK TIP LOADING ANALYSIS AND CRACK GROWTH SIMULATION
To precisely model crack growth, accurate calculations of crack front loading and crack deflection angles are essential. These calculations require solutions of the underlying boundary value problems (BVPs), which are typically obtained by applying numerical methods, e.g., the finite element method (FEM). However, since accuracy and computational cost of the analyses are in general competing aspects, compromises often have to be made in order to generate satisfactory results in acceptable times. In contrast, the use of more efficient methods, both for the solution of the BVP as well as for the subsequent crack tip loading analyses, can substantially lower the computational effort while maintaining desired accuracies. The virtual element method (VEM) is a fairly new discretization scheme for the numerical solution of BVPs, and can be interpreted as a generalization of the FEM. Since the VEM can handle arbitrary polytopal meshes in a straightforward manner, it provides a higher degree of flexibility in the discretization process than the FEM, which turns out to be profitable in terms of both computing times and accuracy. This holds in particular for the simulation of crack growth in 2D and 3D, sparing adaptive re-meshing or the construction of discontinuous element shape functions.
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3D FRACTURE MECHANICS ANALYSIS OF THERMOMAGNETOELECTROELASTIC ANISOTROPIC SOLIDS ACCOUNTING FOR CRACK FACE CONTACT WITH FRICTION
Thermal expansion of the material usually causes existing cracks to close, resulting in the requirement to consider contact problems. The latter are complicated since one should consider the contact of crack faces accounting for sliding, friction, and unknown contact area. This study tries to solve this task by development of the 3D boundary element approach with iterative solver, which can determine the contact zone, sliding of crack faces and account for friction between them. Moreover, multifield materials and various thermal, mechanical, electric and magnetic boundary and contact conditions can be considered.
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CYCLIC EFFECTIVE NEAR-FIELD LOADING BASED ON THE DOMAIN INTEGRAL METHOD
This paper presents a modification of the domain integral method for cyclic loading and crack closure to compute the cyclic effective J-Integral as a near-field loading parameter. The path-dependency of the solution is discussed for different reference states of the field quantities in a cycle. It turns out that refering to the crack opening time point the cyclic effective J-Integral is path-independent for a domain outside the active plastic zone. The validity of this procedure is discussed by comparison with a global energy approach and theoretical field solutions for the J-controlled zone.
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