Analysis of Composite Plates Containing Cracks

1992 ◽  
Vol 114 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Y. W. Kwon
Keyword(s):  
Stress Intensity Factor ◽  
Material Properties ◽  
Composite Plate ◽  
Crack Tip ◽  
Composite Plates ◽  
Unidirectional Composite ◽  
Matrix Crack ◽  
Fiber Breakage ◽  
Fiber Volume ◽  
Element Analysis

Effect of microcracks, such as local matrix crack and fiber breakage, on a macroscale crack in a unidirectional composite plate was studied for various fiber volume fractions, as well as different material properties of fiber and matrix materials. A finite element analysis was performed for this study. It showed that microcracks, located near a macroscale crack tip, resulted in a significant increase of stress intensity factor at the crack tip.

Large Deflection of a Laminated Composite Plate With Different Extensional and Flexural Material Properties

2010 ◽  
Author(s):  
Rifat Arıko¨k ◽  
Zahit Mecitog˘lu
Keyword(s):  
Material Properties ◽  
Composite Plate ◽  
Large Deflection ◽  
Virtual Work ◽  
Flexural Modulus ◽  
Laminated Composite ◽  
Composite Plates ◽  
Equation System ◽  
Laminated Composite Plate ◽  
Element Analysis

This paper presents the large deflection elastic analysis of the hand lay-up composite plates with different extensional and flexural modulus including geometric nonlinearity effects that are taken into account with the von Ka´rma´n large deflection theory of thin plates. Governing equations of the motion are derived by means of the virtual work principle. Then the Galerkin method is applied to reduce the nonlinear coupled differential equations into a nonlinear algebraic equation system. The MATLAB and MATHEMATICA software are used to solve the equation system. Because of the common nonuniformities in hand lay-up fabric laminates such as resin surface layers and unequal layer thickness, the flexural and extensional modulus of such laminated composites are different. By the way, since the bending and in-plane effects are together affect to the nonlinear behavior of a composite laminate, it should give more reliable results when using different flexural and extensional modulus in the analysis. In this study, the results of approximate analysis, ANSYS finite element analysis and experimental study are obtained and compared for a fully-clamped laminated composite plate subjected to a uniform pressure load. The material properties used in the analysis are determined tension and three-point bending tests.

Fracture Mechanics Fatigue Evaluation of a Flowline Clamp Connector Using Finite Element Modeling of a Crack

2019 ◽  
Author(s):  
Curtis Sifford ◽  
Ali Shirani
Keyword(s):  
Finite Element Analysis ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Pressure Vessel ◽  
Crack Tip ◽  
Element Analysis

Abstract This paper presents the application of the rules from ASME Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code for a fracture mechanics evaluation to determine the damage tolerance and fatigue life of a flowline clamp connector. The guidelines from API 579-1 / ASME FFS-1 Fitness-For-Service for the stress analysis of a crack-like flaw have been considered for this assessment. The crack tip is modeled using a refined mesh around the crack tip that is referred to as a focused mesh approach in API 579-1 / ASME FFS-1. The driving force method is used as an alternative to the failure assessment diagram method to account for the influence of crack tip plasticity. The J integral is determined using elastic-plastic finite element analysis and converted to an equivalent stress intensity factor to be compared to the fracture toughness of the material. The fatigue life is calculated using the Paris Law equation and the stress intensity factor calculated from the finite element analysis. The allowable number of design cycles is determined using the safety factors required from Division 3 of the ASME Pressure Vessel Code.

Fracture Mechanics Fatigue Evaluation of a Flowline Clamp Connector Using Finite Element Modeling of a Crack

2018 ◽  
Author(s):  
Curtis Sifford ◽  
Ali Shirani
Keyword(s):  
Finite Element Analysis ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Intensity Factor ◽  
Pressure Vessel ◽  
Crack Tip ◽  
Element Analysis

This paper presents the application of the rules from ASME Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code for a fracture mechanics evaluation to determine the damage tolerance and fatigue life of a flowline clamp connector. The guidelines from API 579-1 / ASME FFS-1 Fitness-For-Service for the stress analysis of a crack-like flaw have been considered for this assessment. The crack tip is modeled using a refined mesh around the crack tip that is referred to as a focused mesh approach in API 579-1 / ASME FFS-1. The driving force method is used as an alternative to the failure assessment diagram method to account for the influence of crack tip plasticity. The J integral is determined using elastic-plastic finite element analysis and converted to an equivalent stress intensity factor to be compared to the fracture toughness of the material. The fatigue life is calculated using the Paris Law equation and the stress intensity factor calculated from the finite element analysis. The allowable number of design cycles is determined using the safety factors required from Division 3 of the ASME Pressure Vessel Code.

Finite Element Analysis on the Stress Intensity Factor under Combined Bending and Torsion Loading

2011 ◽  
Vol 462-463 ◽  
pp. 1325-1330
Author(s):  
Al Emran Ismail ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Mariyam Jameelah Ghazali ◽  
M. Abdulrazzaq
Keyword(s):  
Finite Element Analysis ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Depth ◽  
Crack Tip ◽  
Fe Model ◽  
Element Analysis ◽  
Loading Ratio

The stress intensity factor (SIF) under the combined bending and torsion loading were studied using a finite element (FE) analysis ANSYS. A 20-node iso-parametric element was used to model the crack tip and the square-root singularity of stress/strain was employed by shifting the mid-side node to the ¼ position to the crack tip. Different crack geometries and loading ratios were used and due to the non-symmetrical analysis involved, a full FE model was developed and analyzed. Remotely applied bending and torsion moment were subjected to the FE model and the SIF were then calculated along the crack front under such loadings. The SIF calculated using the finite element analysis (FEA) was compared with those results obtained using an effective combined SIF method. According to the comparisons, the discrepancies were dependent on the normalized coordinate, x/h, the relative crack depth, a/D, the crack aspect ratio, a/b and the loading ratio, .

scholarly journals Dynamic Characteristics of Woven Flax/Epoxy Laminated Composite Plate

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 209
Author(s):  
Venkatachalam Gopalan ◽  
Vimalanand Suthenthiraveerappa ◽  
A. Raja Annamalai ◽  
Santhanakrishnan Manivannan ◽  
Vignesh Pragasam ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Characteristics ◽  
Composite Plate ◽  
Epoxy Composite ◽  
Laminated Composite ◽  
Composite Plates ◽  
Mechanical Tests ◽  
Fe Model ◽  
Element Analysis

Due to the growing environmental awareness, the development of sustainable green composites is in high demand in composite industries, mainly in the automotive, aircraft, construction and marine applications. This work was an attempt to experimentally and numerically investigate the dynamic characteristics of Woven Flax/Bio epoxy laminated composite plates. In addition, the optimisation study on the dynamic behaviours of the Woven Flax/Bio epoxy composite plate is carried out using the response surface methodology (RSM) by consideration of the various parameters like ply orientation, boundary condition and aspect ratio. The elastic constants of the Woven Flax/Bio epoxy composite lamina needed for the numerical simulation are determined experimentally using two methods, i.e., the usual mechanical tests as well as through the impulse excitation of vibration-based approach and made a comparison between them. The numerical analysis on the free vibration characteristics of the composite was carried out using ANSYS, a finite element analysis (FEA) software. The confirmation of the FE model was accomplished by comparing the numerical results with its experimental counterpart. Finally, a comparison was made between the results obtained through the regression equation and finite element analysis.

Predictions of the axial tensile property of the unidirectional composite influenced by microfiber breakage defects

2021 ◽  
pp. 004051752110342
Author(s):  
Tao Liu ◽  
Yuan Gao ◽  
Wei Fan ◽  
Xingzhong Gao ◽  
Jianhua Ma
Keyword(s):  
Mathematical Model ◽  
Volume Fraction ◽  
Tensile Modulus ◽  
Simulation Method ◽  
Unidirectional Composite ◽  
Fiber Breakage ◽  
Micro Computed Tomography ◽  
Fiber Volume ◽  
Computed Tomography Images ◽  
Defect Volume

This paper primarily investigated the effect of fiber breakage defects on tensile properties of the unidirectional composite (UD) using the numerical simulation method. Different kinds of fiber breakage defects were firstly proved to exist in the UD according to the sub-micro computed tomography images at the microscale level. A strict random uniform distribution hypothesis was then proposed to introduce fiber breakage defects into the composite. Numerous microstructural models within random fiber breakage defects were created with the Monte Carlo method to analyze the fiber breakage defect effect on the UD. The results show that the tensile modulus of the UD was reduced by 17% when the fiber breakage defect volume fraction was only 1%, which indicates the effect of this kind of defect was very significant. The fiber volume fraction, defect volume fraction and property all have influences on the decrease of the UD caused by the fiber breakage defect. Finally, we derived a mathematical model to calculate the tensile modulus of the UD based on the numerical results. The proposed mathematical model has an application on the prediction of the axial modulus of the UD or the fiber tow containing large numbers of fiber breakage defects in the composites with complicated structure.

Neural Network Based Buckling Strength Prediction of Laminated Composite Plate with Central Cutout

2014 ◽  
Vol 592-594 ◽  
pp. 560-564 ◽  
Author(s):  
P. Emmanuel Nicholas ◽  
K.P. Padmanaban ◽  
D. Vasudevan ◽  
I. Joseph Selvaraj
Keyword(s):  
Neural Network ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Plate ◽  
Power Transmission ◽  
Laminated Composite ◽  
Composite Plates ◽  
Inspection System ◽  
Laminated Composite Plates ◽  
Element Analysis

Laminated composite plates are greatly used in many applications where high specific strength and stiffness are mandatory. These structures may have holes in order to accommodate windows and doors if it is used for air craft structures or to provide cables and inspection system if it is used in the applications like power transmission systems and automobiles. The laminated composite plates with holes shall be analyzed using finite element analysis. It is necessary to optimize the parameters like thickness, fiber orientation, material and the stacking sequence to obtain the desired characteristics for these structures. But using finite element analysis makes the process more tedious job. With this in mind it is proposed here to construct the artificial neural network to predict the buckling behavior of the composite plate.

Fracture Modeling of an Embedded Crack in Self-Healing Polymers

2012 ◽  
Author(s):  
Mohammad H. Malakooti ◽  
Henry A. Sodano
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Shape Memory ◽  
Healing Process ◽  
Crack Tip ◽  
Original Material ◽  
Self Healing ◽  
Element Analysis ◽  
Elastic Gradient

The healing process exhibited by biological structures has inspired the creation of engineered materials capable of mimicking this behavior, providing adaption to impeding crack propagation and subsequently healing it. Recently, a new approach to self-healing was devised in which a sensing network was combined with shape memory polymers (SMPs) to allow the controlled response of the material to damage. The system was designed such that in the presence of a crack the polymer locally modified its modulus to toughen the damaged region and arrest crack growth. This process is followed by the shape memory response, closing the crack and healing the system. This paper will study the mechanics of the toughening portion of this self-healing system and specifically develop models to predict the stress intensity factor of a crack tip in a nonhomogeneous inclusion. The models will be formulated using finite element analysis (FEA) and a single inclusion model based on Eshelby’s equivalent theory with the elastic gradient defined by a point source thermal load. It will be shown that as the temperature of the crack tip passes the glass transition temperature of the polymer, the stress intensity factor at crack tip decreases to 95% of the original material stress intensity factor. This is due to the formed elastic gradient and deflection of the stress concentration away from the crack tip into the bulk polymer.

scholarly journals Stress Intensity Factor Assessment for the Reinforcement of Cracked Steel Plates Using Prestressed or Non-Prestressed Adhesively Bonded CFRP

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1625
Author(s):  
Emilie Lepretre ◽  
Sylvain Chataigner ◽  
Lamine Dieng ◽  
Laurent Gaillet
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Tip ◽  
Steel Plates ◽  
Experimental Investigations ◽  
Adhesively Bonded ◽  
Element Analysis

The use of adhesively bonded carbon fiber reinforced polymer (CFRP) materials to reinforce cracked steel elements has gained widespread acceptance in order to extend the lifespan of metallic structures. This allows an important reduction of the stress intensity factor (SIF) at the crack tip and thus a significant increase of the fatigue life. This paper deals with the assessment of the SIF for repaired cracked steel plates, using semi-empirical analysis and finite element analysis. Metallic plates with only one crack originating from a center hole were investigated. Virtual crack closure technique (VCCT) was used to define and evaluate the stress intensity factor at crack tip. The obtained modeling results are compared with experimental investigations led by the authors for different reinforcement configurations including symmetrical and non-symmetrical reinforcement, normal modulus and ultra-high-modulus CFRP plates, and pre-stressed CFRP plates. Results show that finite element model (FEM) analysis can obviously simulate the fatigue performance of the CFRP bonded steel plates with different reinforcement configurations. Moreover, a parametric analysis of the influence of the pre-stressing level was also conducted. The results show that an increase of the pre-stressing level results in an increase of the fatigue life of the element.

scholarly journals Analysis of Mode I Periodic Parallel Cracks-Tip Stress Field in an Infinite Orthotropic Plate

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Wenbin Zhao ◽  
Lujuan Yu ◽  
Xuexia Zhang ◽  
Hailing Xie ◽  
Zhixin Hu
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Boundary Value Problem ◽  
Composite Plate ◽  
Crack Tip ◽  
Orthotropic Composite ◽  
Parallel Cracks

The mechanical behavior near crack tip for periodic parallel cracks in an orthotropic composite plate subjected to the uniformly distributed load within the cracks surface is studied. The mechanical problem is turned into the boundary value problem of partial differential equation. By using the periodicity of the hyperbolic function in the complex domain and constructing proper Westergaard stress function, the periodicity of parallel cracks can be removed. Using the complex variable function method and the undetermined coefficients method, the boundary value problem of partial differential equation can be solved with the help of boundary conditions. The analytic expressions for stress intensity factor, stress, and displacement near the crack tip of periodical parallel cracks are obtained. When the vertical distance of cracks tends to infinity, the stress intensity factor degenerates into a single central crack situation. The stress intensity factor around the crack tip of periodic parallel cracks in an orthotropic composite plate depends on the shape factor. The interaction happens between the cracks. Finally, a numerical analysis of the stress and displacement changed with the polar angle is done.

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