scholarly journals Simulation Study of the Damage Mechanisms Appearing in a Cross Ply Composite Material Loaded in Uniaxial Tension

2021 ◽  
Vol 349 ◽  
pp. 01001
Author(s):  
Eleftherios Tsivolas ◽  
Leonidas N. Gergidis ◽  
Alkiviadis S. Paipetis
Keyword(s):  
Composite Material ◽  
Uniaxial Tension ◽  
Multiple Scales ◽  
Crack Density ◽  
Transversely Isotropic ◽  
Matrix Cracking ◽  
Viscous Effects ◽  
Damage Mechanisms ◽  
The Matrix ◽  
Final Crack

The objective of this paper is to predict the different damage mechanisms in multiple scales that can occur in a cross ply composite material loaded in uniaxial tension. The simulated composite material consists of four epoxy-glass fibre layers [0/90]s and the material of each layer is transversely isotropic with viscous effects that occurred from micromechanical homogenization using Mori-Tanaka formulation, extended for visco-elastic materials. For the prediction of the cracking and interlaminar delamination, cohesive contacts were used and the final crack density results were compared with the corresponding experimental ones. Finally a microscale analysis was performed in a Representative Volume Element (RVE) to observe the matrix cracking behaviour in smaller scale.

Matrix Cracking In Brittle-Matrix Composites with Tailored Interfaces

1994 ◽  
Vol 365 ◽  
Author(s):  
Sawai Danchaivijit ◽  
L-Y. Chao ◽  
D. K. Shetfty
Keyword(s):  
Steady State ◽  
Crack Length ◽  
Uniaxial Tension ◽  
Sliding Friction ◽  
Crack Opening ◽  
State Theory ◽  
Matrix Cracking ◽  
Opening Displacement ◽  
The Matrix ◽  
Cracking Stress

ABSTRACTMatrix cracking from controlled through cracks with bridging filaments was studied in a model unidirectional composite of SiC filaments in an epoxy-bonded alumina matrix. An unbonded, frictional interface was produced by moderating the curing shrinkage of the epoxy with the alumina filler and coating the filaments with a releasing agent. Uniaxial tension test specimens (2.5 × 25 × 125 mm) with filament-bridged through cracks were fabricated by a novel two-step casting technique involving casting, precracking and joining of cracked and uncracked sections. Distinct matrix-cracking stresses, corresponding to the extension of the filamentbridged cracks, were measured in uniaxial tension tests using a high-sensitivity extensometer. The crack-length dependence of the matrix-cracking stress was found to be in good agreement with the prediction of a fracture-mechanics analysis that employed a new crack-closure force - crack-opening displacement relation in the calculation of the stress intensity for fiber-bridged cracks. The prediction was based on independent experimental measurements of the matrix fracture toughness (Kcm), the interfacial sliding friction stress (τ) and the residual stress in the matrix (σmI). The matrix-cracking stress for crack lengths (2a) greater than 3 mm was independent of the crack length and agreed with the prediction of the steady-state theory of Budiansky, Hutchinson and Evans[2]. Tests on specimens without the deliberately introduced cracks indicated a matrix-cracking stress significantly higher than the steady-state stress.

Experimental Characterization of Matrix Cracking Behavior in Thermally Cycled CFRP Laminates

2002 ◽  
Vol 11 (3) ◽  
pp. 287-305 ◽  
Author(s):  
Shinji Ogihara ◽  
Akira Kobayashi ◽  
Takamoto Ishiguro ◽  
Nobuo Otani
Keyword(s):  
Thermal Cycling ◽  
Crack Density ◽  
Tensile Loading ◽  
Matrix Crack ◽  
Matrix Cracking ◽  
Thermal Cycles ◽  
Critical Energy Release Rate ◽  
Cracking Behavior ◽  
Cfrp Laminates ◽  
The Matrix

The effect of thermal cycling on the mechanical properties of composite materials is an important issue in engineering, especially in their applications to the space environment. The present study concerned with the experimental study of both the thermal cycling induced matrix cracking and the effect of thermal cycling on the matrix cracking behavior under tensile loading in CFRP laminates. Two kinds of carbon/epoxy systems, T800H/3631 and T300/2500, are used for the laminate configurations of (0/90)s and (90/0)s. The specimens are thermally cycled between −196 and 100°C. Thermal cycling tests are performed up to 1000 cycles. The polished edge surfaces of specimens are examined by the replica technique, and then the matrix crack density is measured as a function of the number of thermal cycles. It is found that the first matrix cracking in (0/90)s and (90/0)s laminates occurs at almost the same numbers of thermal cycles. It is also found that the matrix crack density increases more rapidly in (0/90)s laminates than in (90/0)s laminates in both material systems. To investigate the effect of thermal cycling on matrix cracking behavior under tensile loading, a series of tensile tests on thermally cycled specimens are performed. The effect of thermal cycling on matrix cracking under tension is evaluated in terms of the change in the critical energy release rate and the critical stress for matrix cracking.

Shrinkage stresses near a discontinuity in a fibre composite material

1972 ◽  
Vol 7 (1) ◽  
pp. 54-60 ◽  
Author(s):  
N K Asamoah ◽  
W G Wood
Keyword(s):  
Composite Material ◽  
Stress Concentration ◽  
Tensile Stress ◽  
Fibre Composite ◽  
Matrix Cracking ◽  
Axial Tensile ◽  
Fibre Composites ◽  
The Matrix ◽  
Fibre Composite Material

The technique of photothermoelasticity has been used to analyse the shrinkage stresses near to a discontinuity in a model of a fibre composite material. The axial-shrinkage stresses away from the discontinuity are tensile in the matrix and compressive in the fibre, while, between the ends of the discontinuous fibre they are wholly compressive. Under an applied axial tensile stress the presence of shrinkage stresses would therefore tend to reduce the tendency for matrix cracking to occur in the gap between the fibre ends where the tensile-stress concentration is high. However, if the fibres are close together the shrinkage stresses can themselves cause matrix cracking. These observations are reinforced by the results of other work on the strength of single- and multiple-fibre composites.

Semi-Analytical Modeling of Progressive Damage in Twill Woven Textile Composites

2001 ◽  
Author(s):  
Pramod Chaphalkar ◽  
Ajit O. Kelkar
Keyword(s):  
Composite Material ◽  
Effective Properties ◽  
Textile Composites ◽  
Matrix Cracking ◽  
Woven Fabric ◽  
Woven Composites ◽  
Matrix Cracks ◽  
Structural Applications ◽  
Matrix Properties ◽  
The Matrix

Abstract Various alternative composite materials like, textile composites, especially woven, are being developed and tried in place of conventional multidirectional laminates, because they have better properties in mutually orthogonal directions and out of plane properties than the multidirectional laminates. In structural applications, predictions of the elastic modulii, Poisson’s ratios from the weave architecture and the properties of the constituents are required. There are various parameters that characterize the weave architecture of woven laminate composites. In repeated loading, the matrix cracking occurs, degrading matrix properties. This in turn degrades the effective properties of the woven composites. Analytical models are necessary to study the effects of these parameters on the behavior of woven fabric composites and to design efficient woven structure for particular application. The objective of the current paper is to study the effect of matrix cracking on the effective properties of the twill woven composites by degrading the matrix properties. First the effective properties of the composite material, without any matrix cracks, are determined by using an analytical model, which predicts the stiffness of the twill woven composites. This model takes into account effects of the actual fabric structure with various tow cross sections by considering tow undulations and continuity along both the fill and warp directions. In twill woven composites, there is a weaker matrix along with the stronger medium i.e. the glass fibers. The matrix first fails and then the load is transferred to the fibers. The matrix properties are degraded in the resin pockets and also in the transverse tows only. This is because normally matrix cracking first occurs in the transverse tows (cracks originate in the tows that run in the transverse direction to the loading). The degradation of the properties includes the Young’s Modulus and the Poisson’s ratio of the resin. With these modified properties of the resin, the homogeneous properties of the transverse tows are calculated. At each degradation step the effective properties of the composite material are evaluated. This progressive failure is continued till the matrix loses most of its strength.

Micromechanical prediction of damage due to transverse ply cracking under fatigue loading in composite laminates

2017 ◽  
Vol 36 (5) ◽  
pp. 377-395 ◽  
Author(s):  
Bjian Mohammadi ◽  
Milad Rohanifar ◽  
Davood Salimi-Majd ◽  
Amin Farrokhabadi
Keyword(s):  
Experimental Data ◽  
Composite Laminates ◽  
Damage Mechanics ◽  
Crack Density ◽  
Strain Energy Release ◽  
Fatigue Loading ◽  
Matrix Cracking ◽  
Finite Element Software ◽  
Stiffness Reduction ◽  
The Matrix

To predict the matrix microcracking of laminated composites under fatigue loading, a novel energy based model is presented in the framework of micromechanics. For this purpose, strain energy release rate (SERR) of microcracks which had been derived previously for the whole laminate, is developed for a lamina, and then is calculated using a stress transfer-based stiffness reduction method. The advantages of the proposed method include its capability to predict the matrix cracking of general lay-ups based on the local stresses and stiffnesses of each plies separately and not being limited to a special stacking sequence. In order to predict micro-cracking propagation of composites under cyclic loading, the coefficients of the modified Paris law are extracted using the available experimental data of crack density–cycle curves. Then using multi-scale modelling and continuum damage mechanics concept, the proposed algorithm is implemented in ANSYS finite element software, as a new user defined material (Usermat). The static progress of failure on [45/−45]s laminate is simulated and the obtained results are compared with the existing experimental data in a good agreement. Finally, the results of implemented fatigue algorithm for different cross-ply laminates under different stress levels are obtained and compared with the available experimental data.

The microstructure of a TiB2/Ti-47 Al composite material

1989 ◽  
Vol 47 ◽  
pp. 674-675
Author(s):  
O. Popoola ◽  
A.H. Heuer ◽  
P. Pirouz
Keyword(s):  
Composite Material ◽  
Ion Beam ◽  
Chemical Properties ◽  
Intermetallic Alloys ◽  
Transmission Electron ◽  
Diamond Polishing ◽  
Al Composite ◽  
The Matrix ◽  
Argon Ion ◽  
And Chemical Properties

The addition of fibres or particles (TiB2, SiC etc.) into TiAl intermetallic alloys could increase their toughness without compromising their good high temperature mechanical and chemical properties. This paper briefly discribes the microstructure developed by a TiAl/TiB2 composite material fabricated with the XD™ process and forged at 960°C.The specimens for transmission electron microscopy (TEM) were prepared in the usual way (i.e. diamond polishing and argon ion beam thinning) and examined on a JEOL 4000EX for microstucture and on a Philips 400T equipped with a SiLi detector for microanalyses.The matrix was predominantly γ (TiAl with L10 structure) and α2(TisAl with DO 19 structure) phases with various morphologies shown in figure 1.

Effect of temperature on matrix multicracking evolution of C/SiC fiber-reinforced ceramic-matrix composites

2020 ◽  
Vol 39 (1) ◽  
pp. 189-199
Author(s):  
Longbiao Li
Keyword(s):  
Strain Energy ◽  
Ceramic Matrix Composites ◽  
Critical Value ◽  
Matrix Cracking ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Temperature Dependent ◽  
Damage State ◽  
The Matrix ◽  
Sic Composites

AbstractIn this paper, the temperature-dependent matrix multicracking evolution of carbon-fiber-reinforced silicon carbide ceramic-matrix composites (C/SiC CMCs) is investigated. The temperature-dependent composite microstress field is obtained by combining the shear-lag model and temperature-dependent material properties and damage models. The critical matrix strain energy criterion assumes that the strain energy in the matrix has a critical value. With increasing applied stress, when the matrix strain energy is higher than the critical value, more matrix cracks and interface debonding occur to dissipate the additional energy. Based on the composite damage state, the temperature-dependent matrix strain energy and its critical value are obtained. The relationships among applied stress, matrix cracking state, interface damage state, and environmental temperature are established. The effects of interfacial properties, material properties, and environmental temperature on temperature-dependent matrix multiple fracture evolution of C/SiC composites are analyzed. The experimental evolution of matrix multiple fracture and fraction of the interface debonding of C/SiC composites at elevated temperatures are predicted. When the interface shear stress increases, the debonding resistance at the interface increases, leading to the decrease of the debonding fraction at the interface, and the stress transfer capacity between the fiber and the matrix increases, leading to the higher first matrix cracking stress, saturation matrix cracking stress, and saturation matrix cracking density.

An Overall Approach for Microcrack and Inhomogeneity Toughening in Brittle Solids

1999 ◽  
Vol 15 (2) ◽  
pp. 57-68
Author(s):  
Huang Hsing Pan
Keyword(s):  
Poisson Ratio ◽  
Crack Density ◽  
Mean Field ◽  
Analytic Form ◽  
Density Parameter ◽  
Brittle Solids ◽  
The Matrix ◽  
Microcrack Toughening ◽  
Average Quantity ◽  
The Mean

ABSTRACTBased on the weight function theory and Hutchinson's technique, the analytic form of the toughness change near a crack-tip is derived. The inhomogeneity toughening is treated as an average quantity calculated from the mean-field approach. The solutions are suitable for the composite materials with moderate concentration as compared with Hutchinson's lowest order formula. The composite has the more toughened property if the matrix owns the higher value of the Poisson ratio. The composite with thin-disc inclusions obtains the highest toughening and that with spheres always provides the least effective one. For the microcrack toughening, the variations of the crack shape do not significantly affect the toughness change if the Budiansky and O'Connell crack density parameter is used. The explicit forms for three types of the void toughening and two types of the microcrack toughening are also shown.

Stochastic Aspects of Matrix Cracking in Brittle Matrix Composites

1993 ◽  
Vol 115 (3) ◽  
pp. 314-318 ◽  
Author(s):  
S. M. Spearing ◽  
F. W. Zok
Keyword(s):  
Matrix Cracking ◽  
Matrix Composites ◽  
Brittle Matrix ◽  
Tensile Response ◽  
Brittle Matrix Composites ◽  
Crack Interactions ◽  
The Matrix ◽  
Interface Slip ◽  
Bridging Fibers

A computer simulation of multiple cracking in fiber-reinforced brittle matrix composites has been conducted, with emphasis on the role of the matrix flaw distribution. The simulations incorporate the effect of bridging fibers on the stress required for cracking. Both short and long (steady-state) flaws are considered. Furthermore, the effects of crack interactions (through the overlap of interface slip lengths) are incorporated. The influence of the crack distribution on the tensile response of such composites is also examined.

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