Fatigue life estimation and crack propagation analysis of orthotropic lamina using xiga methodology. Pdf adaptive phase field modelling of crack propagation. Orthotropic material properties corresponding to the laminae were assigned to partitions reproducing the stacking sequence. The highcycle fatigue characteristics focused on the behavior of the transverse crack growth up to 10 8 cycles were investigated using quasiisotropic carbon fiber reinforced plastic cfrp laminates whose stacking sequence was 4504590 s. The procedure does not require a threedimensional analysis and is used for any nonhomogeneous laminated. The stress boundary conditions of each unit cell are obtained from the finite element analysis of laminates in each step of loading. Separation of crack extension modes in orthotropic delamination models jackl. Detailed experimental observations were made on the initiation and growth of individual cracks in 45 and 90 plies. Kumosa m, and eggers h 1990, mixedmode fracture analysis of orthotropic laminates by local and global energy methods, numerical methods in fracture.
Influence of interfaces on the fatigue crack growth in ultrafine grained laminates produced by accum. The presence of a crack was modeled by removing elements in the adhesive layer up to the desired crack length. Abstract in the analysis of an interface crack between dissimilar elastic materials, the mode of crack extension is typically not unique, due to oscillatory behavior of neartip stresses and. The strong and weak discontinuous functions along the thickness direction are adopted to simulate. Multiscale analysis and experimental validation of crack. Matrix crack growth behaviour under quasistatic and mechanical fatigue loadings has been studied in quasiisotropic 090. Extended layerwise method for laminated composite plates. Methods for calculating stress intensity factors for interfacial cracks between two orthotropic solids. Transverse cracking is probably the first and most dominant mode of damage in composite materials.
Stressdistribution around pinloaded hole for orthotropic. Bending and buckling of orthotropic plates and laminates. It allows modeling crack by standard finite element method. In this paper a boundaryelement formulation for analysis of crack growth in homogeneous orthotropic laminates is presented. Separation of crack extension modes in orthotropic. On matrix crack growth in quasiisotropic laminatesii. Dynamic crack propagation analysis of orthotropic media by the. The total strain energy release rate of a homogeneous orthotropic cracked beamlike structure is calculated using timoshenkos beam theory. Schapery and davidson 1990 1241 proposed a crack tip element to investigate the crack growth. In the numerical simulations, a simplified computational strategy only focusing on the damage of the. The pin loading effects and bypass loading effects are incorporated in two different tested joints. In the two phase model phases 1 and 2 are joined in a homogeneous matrix and designated as phase 2.
Crack analysis in orthotropic media using the extended. Aliabadia mh, sollero p 1998 crack growth analysis in homogeneous orthotropic laminates. The dual boundaryelement method was formulated for crack growth analysis in homogeneous orthotropic laminates. Model development under conditions of plane strain or appears as an elliptical region of a thin plate under conditions of generalized plane stress. Stress intensity factor evaluation of anisotropic cracked. A robust crack growth prediction tool has been developed for a class of hybrid skin materials known as fibre metal laminates fmls which has been. An extended finite element method has been proposed for modeling crack in orthotropic media. Matrix cracking and delaminations in orthotropic laminates subjected to freezethaw. Postbuckling of a thin film strip delamination in a. Fatigue crack growth analysis of a homogeneous plate in the presence of. In the three phase model we designated the fiber as phase 1, matrix as phase 2, and cracks as phase 3. It may be used as a criterion for the onset of delamination growth in nonhomogeneous laminated composites.
Fatigue life prediction for transverse crack initiation of. Influence of interfaces on the fatigue crack growth in. Transverse crack onset and growth in crossply laminates. Coupled quasihomogeneous orthotropic laminates springerlink. Recently, the effects of initial defects on crack initiation were. Transverse crack growth behavior considering freeedge.
Alderliesten 1 1technical university of delft, delft, the netherlands abstract. Composite laminates article about composite laminates by. Application of a coupled stress and energy criterion i. Arman afshar, saeed hatefi ardakani and soheil mohammadi, stable discontinuous spacetime analysis of dynamic interface crack growth in orthotropic bimaterials using oscillatory crack tip enrichment functions, international journal of mechanical sciences, 10. The extended finite element method xfem, which can simplify and enhance the modeling of strong and weak discontinuities in material and geometric behaviours, is applied to stress analysis of composite laminates containing interlaminar delamination. The basic method can be used to describe not only onedimensional delamination growth for example, free edge delamination but also twodimensional delamination growth contoured delamination. Thus, this model is not suitable for crack growth predictions. It is assumed that 1 there is perfect bonding between layers. Xfem, delamination, orthotropic composite laminates, interface crack. Buckling analysis of delaminated laminates with consideration of contact in buckling mode. Dynamic analysis of a viscoelastic orthotropic cracked body. A mesoscopic fe analysis that reproduced the nonlinear offaxis deformation of each ply was performed to obtain the deformation histories at the locations where.
An interface crack analysis is presented for further understanding the. These calculations were based on finiteelement analysis for five laminates. Observation of transverse crack initiation and growth. Monitoring of fatigue crack growth in composite adhesively. The analysis of the test results shows that pin loading dominates the crack growth only in the vicinity of the. Effect of delamination of axially loaded homogeneous laminated plates.
On matrix crack growth in quasiisotropic laminatesi. To assess the fatigue behavior in the highcycle region, fatigue tests were conducted at a frequency of 100 hz in. The initiation behavior of transverse cracks under static loading has also been evaluated 7,8,14,15,16. Two symmetric cracks having the same length were modeled at both the ends of the overlap. It was shown that the orthotropic material properties have considerable influence on the crack path. Matrix cracking and delaminations in orthotropic laminates. This article presents a threedimensional extended finite element xfem approach for numerical simulation of delamination in unidirectional composites under fracture mode i. Th e analytical part uses a theory of anisotropic plates and the experimental one, strain gages to obtain the strains generated on. Several examples were presented to demonstrate the efficiency of the proposed method.
Multiple matrix crack growth behaviour in a quasiisotropic 090. Rather, a sideways crack branched in the direction of tension and normal to the notch direction may typically develop fig. Dynamic stress intensity factors of an interfacial crack. To avoid instability during simulations, a critical cohesive zone length is defined such that userdefined. Investigation on the crack behaviour in kevlar 49 based. The multiplication and propagation behaviors of transverse cracks in cfrp laminates have been quantitatively evaluated through experiments and analysis under static and fatigue loading 7,8,9,10,11,12. Energy balance and the speed of crack growth in a compressed plate with delamination. This paper provides an experimental investigation into the pin loading effects on the crack growth behaviour in fibre metal laminates. In this study, a multiscale approach consisting of a laminate scale fe analysis and a microscopic periodic unit cell puc analysis was developed to predict the onset of matrix cracks in the 90. Analysis of energy release rate for cracked laminates. Modeling delamination in composite laminates using. The inertial effects are modeled using the dual reciprocity boundary elements method. Fracture analysis of composites by time independent moving. Characterization and analysis of delamination fracture in composites.
Characterization and analysis of delamination fracture in. Orthotropic elastic properties assessment of sandwich. A cohesive zone model in front of the crack tip is used to include interface material nonlinearities. Crack growth analysis in anisotropic solids request pdf. The extended isogeometric analysis xiga is the combination of the. The left and right images of the upper part of figure 5 were observed using afm. Based on classical plate theory cpt, they got an expression for. We have shown, by analysis and experiment, that it is possible, for certain types of orthotropic laminates, to determine completely the inplane elastic properties membrane stiffnesses, compliances and engineering constants from a total of three pure tension tests an offaxis.
Representative models have been developed to describe the sequential matrix cracking events observed from the experiments, as reported in part i of this paper. Q ijthe components in the matrices of inplane stress and strain are. The study is then extended to the analysis of orthotropic fgms. Crack kinking at the tip of a mode i crack in an orthotropic solid h.
The numerical method that is used to perform the modeling of the crack is the dual boundary element method. In the past, crack paths in composite materials such as in laminates, particle or fiber reinforced composites were studied e. Effect of delamination of axially loaded homogeneous. Figure 5 shows the growth process of a micro crack originating from the initial defects in the crossply 0 2 90 12 s laminates formed from the t800s2592, v f 68% prepreg. The presence in a laminate of plies oriented at 90 with respect to the.
This study was based on a twodimensional finiteelement analysis of stresses in an orthotropic laminate that is loaded by a frictionless steel pin in a circular hole of the same diameter. The xiga for dynamic cracked isotropicorthotropic media is described in section 3. The element a ij, b ij and d ij, are, respectively, the membrane rigidities, coupling rigidities and flexural rigidities of the plate. An experimentalnumerical investigation into the main driving. Abstract the competition between crack penetration and crack kinking is addressed for a mode i macroscopic crack in an orthotropic elastic solid. Developing new enrichment functions for crack simulation. Laminate stacking sequence configurations with quasihomogeneous properties are derived, whereby the inplane and outofplane stiffness properties are concomitant. Deepdyve is the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Delamination analysis of composites by new orthotropic. Q ij are the reduced stiffness coefficients, which can be related to the more familiar engineering moduli by. For stable intersonic crack growth this is the only speed at which the energy release rate is finite. To achieve this aim a discontinuous function and twodimensional asymptotic crack tip displacement fields are used in a classical finite element approximation enriched with the framework of partition of unity.
Having these boundary conditions and using the above mentioned procedure the stress and. The method allows for analysis of the whole crack propagation pattern on an. Laboratory test results using laminates made of an as350106 graphite epoxy system are presented along with analytically predicted results. The stacking sequence configurations contain equalthickness layers and identical orthotropic properties, differing only by their orientations, which are represented by standard angle and. The influence of temperature on crack growth in fibre. An experimental investigation into pin loading effects on. Stress state characterization of delamination cracks in core. Jaswon and bhargava8 obtained explicit solutions in these cases by an approach based on complex variable. The emphasis here is on delamination between the composite layers, rather than cracking through the layers. In this paper, transverse cracking of crossply 0290ns n 2,3,4 laminates under uniaxial tension load was studied by means of experimental and numerical methods.
For homogeneous, anisotropic and linear elastic solids, the biem or bem has also been successfully applied to elastostatic crack analysis, although the corresponding elastostatic fundamental. The stress intensity factor and strain energy release rate for a crack situated at the interface between a non. It is observed that, if the gradation in fracture properties is neglected, the material gradient plays a secondary role, with the. Stochastic mixed mode stress intensity factor of center. Stresses were calculated for orthotropic laminate plate loaded by a frictionless pin in a circular hole of the same diameter. The second example is a crack growth simulation, which is the crack extension analysis adding to the crack tip small straight elements in a direction predicted by.
To achieve this aim a discontinuous function and twodimensional asymptotic cracktip displacement fields are used in a classical finite element approximation enriched with the framework of partition of unity. Because the crack tip is fully embedded in a homogeneous. In this paper, the extended layerwise method xlwm, which was developed for laminated composite beams with multiple delaminations and transverse cracks li et al. Analysis of the intersonic crack growth in anisotropic materials was developedby piva and hasan 12, huang et. A description of fatigue crack growth, paris law, and finite element usage. A simplified computational strategy focused on resin. Finiteelement models were developed for wide ranges of widthto. The selfconsistent analysis of the cracked composite, as outlied. Crack growth analysis in homogeneous orthotropic laminates.
The aim of this paper is to present a procedure to perform the evaluation of dynamic stress intensity factors of composite cracked sheets. Dynamic crack analysis in isotropicorthotropic media via extended. The influence of temperature on crack growth in fibre metal laminates c. Crack simulation in fem has been performed by a number of methods such as the continuous smeared crack model and several discontinuous approaches such as the discrete interelement crack model, the discrete crack model, and the discrete elementbased model 29. Pdf fatigue crack growth analysis of a homogeneous plate in the. The total strain energy release rate is modified by including the energy spent in the deformation of the beam near the crack tip. Damage analysis of laminated composites using a new.