Three-dimensional modeling of intersonic shear-crack growth in asymmetrically loaded unidirectional composite plates

2002-12
Yu, C.
Pandolfi, A.
Ortiz, M.
Çöker, Demirkan
Rosakis, A.J.
Show full item record
275
views
0
downloads
An anisotropic cohesive model of fracture is applied to the numerical simulation of Coker and Rosakis experiments (2001). In these experiments, a unidirectional graphite-epoxy composites plate was impacted with a projectile, resulting in an intersonic shear-dominated crack growth. The simulations account for explicit crack nucleation-through a self-adaptive remeshing procedure-crack closure and frictional sliding. The parameters used in the cohesive model are obtained from quasi-static fracture experiments, and successfully predict the dynamic fracture behavior. In keeping with the experiments, the calculations indicate that there is a preferred intersonic speed for locally steady-state growth of dynamic shear cracks, provided that suffcient energy is supplied to the crack tip. The calculations also show that the crack tip can attain speeds in the vicinity of the longitudinal wave speed in the direction of the fibers, if impacted at higher speeds. In addition, a double-shock which emanates from a finite size contact region behind the crack tip is observed in the simulations. The predicted double-shock structure of the near-tip fields is in close agreement with the experimental observations. The calculations additionally predict the presence of a string of surface hot spots which arise following the passage of the crack tip. The observed and computed hot spot structures agree both in geometry as well as in the magnitude of the temperature elevation. The analysis thus suggests intermittent friction as the origin of the experimentally observed hot spots. © 2002 Elsevier Science Ltd. All rights reserved.
3D finite elements, Anisotropic cohesive element, Frictional contact, Intersonic shear crack growth, Unidirectional composites, Self-adaptive remeshing
https://hdl.handle.net/11511/28188
International Journal of Solids and Structures
Department of Aerospace Engineering, Article

Suggestions

Three-dimensional structural topology optimization of aerial vehicles under aerodynamic loads
Oktay, Erdal; AKAY, HASAN UMUR; Şehitoğlu, Onur Tolga (2014-03-20)
A previously developed density distribution-based structural topology optimization algorithm coupled with a Computational Fluid Dynamics (CFD) solver for aerodynamic force predictions is extended to solve large-scale problems to reveal inner structural details of a wing wholly rather than some specific regions. Resorting to an iterative conjugate gradient algorithm for the solution of the structural equilibrium equations needed at each step of the topology optimizations allowed the solution of larger size p...
A comparative study on biodegradation and mechanical properties of pressureless infiltrated Ti/Ti6Al4V-Mg composites
ESEN, ZİYA; Butev, Ezgi; Karakas, M. Serdar (2016-10-01)
The mechanical response and biodegradation behavior of pressureless Mg-infiltrated Ti-Mg and Ti6Al4V-Mg composites were investigated by compression and simulated body fluid immersion tests, respectively. Prior porous preforms were surrounded uniformly with magnesium as a result of infiltration and the resultant composites were free of secondary phases and intermetallics. Although the composites' compressive strengths were superior compared to bone, both displayed elastic moduli similar to that of cortical b...
A Three dimensional mixed formulation nonlinear frame finite element based on hu-washizu functional
Soydaş, Ozan; Sarıtaş, Afşin; Department of Civil Engineering (2013)
A three dimensional nonlinear frame finite element is presented in this analytical study by utilizing Hu-Washizu principle with three fields of displacement, strain and stress in the variational form. Timoshenko beam theory is extended to three dimensions in order to derive strains from the displacement field. The finite element approximation for the beam uses shape functions for section forces that satisfy equilibrium and discontinous section deformations along the beam. Nonlinear analyses are performed by...
Simulation of orthogonal metal cutting by finite element analysis
Bil, Halil; Kılıç, Engin; Tekkaya, Erman; Department of Mechanical Engineering (2003)
The aim of this thesis is to compare various simulation models of orthogonal cutting process with each other as well as with various experiments. The effects of several process parameters, such as friction and separation criterion, on the results are analyzed. As simulation tool, commercial implicit finite element codes MSC.Marc, Deform2D and the explicit code Thirdwave AdvantEdge are used. Separation of chip from the workpiece is achieved either only with continuous remeshing or by erasing elements accordi...
Three-dimensional numerical modelling of temporal and spatial pattern formation in a dc-driven gas discharge-semiconductor system
Rafatov, İsmail (IOP Publishing, 2016-12-01)
A three-dimensional numerical model is developed and applied to study the temporal and spatial pattern formation in the planar layered system, consisting of a glow discharge layer, coupled to a high ohmic semiconductor layer. The whole system is sandwiched between two planar electrodes, to which a dc voltage is applied.
Citation Formats
C. Yu, A. Pandolfi, M. Ortiz, D. Çöker, and A. J. Rosakis, “Three-dimensional modeling of intersonic shear-crack growth in asymmetrically loaded unidirectional composite plates,” International Journal of Solids and Structures, pp. 6135–6157, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/28188.
METU IIS - Integrated Information Service open@metu.edu.tr