scholarly journals Modelling Cracked Cross-Ply Laminates with Delamination Buckling

2018 ◽  
Vol 774 ◽  
pp. 60-65 ◽  
Author(s):  
A. Köllner ◽  
Maria Kashtalyan ◽  
Igor Guz ◽  
C. Völlmecke
Keyword(s):  
Structural Stability ◽  
Analytical Framework ◽  
Matrix Crack ◽  
Stability Behavior ◽  
Matrix Cracks ◽  
Stiffness Properties ◽  
Delamination Buckling ◽  
Plane Compression ◽  
Constrained Model ◽  
Modelling Approach

The mechanical behavior of cross-ply laminates loaded under in-plane compression containing matrix cracks and delaminations is investigated in order to study their influence on the structural stability behavior. This is done by employing a semi-analytical modelling approach which comprises an analytical framework for a structural stability analysis of damageable structures and the Equivalent Constrained Model for deriving reduced stiffness properties of the cracked layers. Cross-ply laminates with varying delamination depths as well as varying matrix crack densities are studied.

Matrix and interface microcracking in carbon fiber/polymer structural micro-battery

2019 ◽  
Vol 53 (25) ◽  
pp. 3615-3628 ◽  
Author(s):  
Johanna Xu ◽  
Janis Varna
Keyword(s):  
Carbon Fiber ◽  
Energy Release ◽  
Crack Growth ◽  
Matrix Crack ◽  
Matrix Interface ◽  
Release Rates ◽  
Matrix Cracks ◽  
The Matrix ◽  
Energy Release Rates ◽  
Coating Matrix

In this paper, the propagation of radial matrix cracks and debond cracks at the coating/matrix interface in unidirectional carbon fiber structural micro-battery composite are studied numerically. The micro battery consists of a solid electrolyte-coated carbon fiber embedded in an electrochemically active polymer matrix. Stress analysis shows that high hoop stress in the matrix during charging may initiate radial matrix cracks at the coating/matrix interface. Several 2-D finite element models of the transverse plane with different arrangements of fibers and other matrix cracks were used to analyze the radial matrix crack growth from the coating/matrix interface of the central fiber in a composite with a square packing of fibers. Energy release rates of radial cracks along two potential propagation paths are calculated under pure electrochemical loading. The presence of a radial matrix crack imposes changes in the stress distribution along the coating/matrix interface, making debonding relevant for consideration. Results for energy release rates show that the debond crack growth is governed by mode II.

Stability Analysis of Bridged Cracks in Brittle Matrix Composites

1993 ◽  
Vol 115 (1) ◽  
pp. 127-138 ◽  
Author(s):  
R. Ballarini ◽  
S. Muju
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Opening ◽  
Matrix Crack ◽  
Matrix Composites ◽  
Brittle Matrix ◽  
Matrix Cracks ◽  
Brittle Matrix Composites ◽  
Propagating Crack

The bridging of matrix cracks by fibers is an important toughening mechanism in fiber-reinforced brittle matrix composites. This paper presents the results of a nonlinear finite element analysis of the Mode I propagation of a bridged matrix crack in a finite size specimen. The composite is modeled as an orthotropic continuum and the bridging due to the fibers is modeled as a distribution of tractions that resist crack opening. A critical stress intensity factor criterion is employed for matrix crack propagation, while a critical crack opening condition is used for fiber failure. The structural response of the specimen (load-deflection curves) as well as the stress intensity factor of the propagating crack is calculated for various constituent properties and specimen configurations for both tensile and bending loading. By controlling the length of the bridged crack, results are obtained that highlight the transition from stable to unstable behavior of the propagating crack.

Fracture Design of Metallic Matrix Crack for Bi-Materials

2006 ◽  
Vol 306-308 ◽  
pp. 7-12 ◽  
Author(s):  
You Tang Li ◽  
Chang Feng Yan
Keyword(s):  
Finite Element Method ◽  
Stress Singularity ◽  
Engineering Application ◽  
Metallic Matrix ◽  
Matrix Crack ◽  
The Finite Element Method ◽  
Three Point Bending ◽  
Matrix Cracks ◽  
Uniform Tension ◽  
Practical Engineering

The fracture designs of metallic matrix crack for bi-materials were studied. The stress field and displacement field of plane matrix crack was setup at first. Then the finite element method is used to analyses the stress singularity of matrix cracks between different materials. The solutions of stress singularity of a cracked bi-materials beam under uniform tension, and the three-point bending of bi-materials specimen were computed. The result lays a theoretic and applied foundation for the practical engineering application of metallic matrix crack for bi-materials.

Stability Analysis of Bridged Cracks in Brittle Matrix Composites

1991 ◽  
Author(s):  
Roberto Ballarini ◽  
Sandeep Muju
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Opening ◽  
Matrix Crack ◽  
Matrix Composites ◽  
Brittle Matrix ◽  
Matrix Cracks ◽  
Brittle Matrix Composites ◽  
Propagating Crack

The bridging of matrix cracks by fibers is an important toughening mechanism in fiber reinforced brittle matrix composites. This paper presents the results of a non-linear finite element analysis of the Mode-I propagation of a bridged matrix crack in a finite size specimen. The composite is modeled as an orthotropic continuum and the bridging due to the fibers is modeled as a distribution of tractions which resist crack opening. A critical stress intensity factor criterion is employed for matrix crack propagation while a critical crack opening condition is used for fiber failure. The structural response of the specimen (load-deflection curves) as well as the stress intensity factor of the propagating crack are calculated for various constituent properties and specimen configurations for both tensile and bending loading. By controlling the length of the bridged crack results are obtained which highlight the transition from stable to unstable behavior of the propagating crack.

Bifurcation and Disaggregation in Lowry—Garin Derivative Models: Theory, Calibration, and Case Study

1988 ◽  
Vol 20 (9) ◽  
pp. 1253-1267 ◽  
Author(s):  
P Yi ◽  
Y Chan
Keyword(s):  
Model Calibration ◽  
Bifurcation Theory ◽  
Spatial Interaction ◽  
Calibration Procedure ◽  
Analytical Framework ◽  
Medium Size ◽  
Disaggregate Model ◽  
Constrained Model ◽  
Calibration Techniques

The classic Lowry—Garin model is reexamined in light of advances in bifurcation theory and disaggregate model calibration techniques. A procedure for disaggregate calibration of the multipliers used in the economic-base component of the model is presented. Also given is an endogenous calibration procedure to include zonal constraints into the spatial interaction part of the unconstrained Lowry—Garin model. This is accomplished through the use of only two simple parameters which have important physical interpretations regarding the sensitivity of transportation improvements. Bifurcation conditions are then specified for the constrained model in both the aggregate and disaggregate cases. Through a case study of a medium-size city, the disaggregate calibration approach was found to produce better replication of the observed development pattern. Also the endogenous way of embedding zonal constraints in the two aforementioned parameters was found to be extremely efficient computationally. Most importantly, the analytical framework offers a transparent way of explaining urban development, including the prediction of precipitous developments, thus relieving much of the burden of traditional simulation approaches which tend to be cumbersome and analytically intractable.

Multi-Physics Modeling Approach in All Terrain Vehicle Longitudinal Dynamics

2006 ◽  
Author(s):  
A. Am. Sharaf ◽  
G. Mavros ◽  
H. Rahnejat ◽  
P. D. King
Keyword(s):  
Degrees Of Freedom ◽  
Model Development ◽  
Operating Conditions ◽  
User Friendliness ◽  
Design Engineers ◽  
Component Selection ◽  
Stiffness Properties ◽  
Body Dynamics ◽  
Physics Modeling ◽  
Modelling Approach

This paper presents a detailed 4×4 off-road vehicle modelling method, based on a multi-physics approach. A full drivetrain system including all aspects of rotational inertial dynamics, friction, damping and stiffness properties is integrated with a fourteen-degrees-of-freedom vehicle model including body dynamics, kinematics, suspension and wheel dynamics as well as the terramechanical phenomena between tyres and soft soils. The interaction between all these modules is implemented in the MATLAB/SIMULINK/SimDriveline environment. The concepts of modularity, flexibility, and user-friendliness were emphasized during model development. The model is developed in order to provide design engineers with the capability to investigate effects of component selection and to develop control systems and automatic optimization processes for off-road 4×4 vehicles. While the modelling approach can be used for a wide variety of operating conditions, the present work focuses on the analysis of the contribution of different aspects on the off-road traction of 4×4 vehicles.

Matrix Crack Detection of CFRP Laminates in Cryogenic Temperature Using Electrical Resistance Change Method

2006 ◽  
Vol 321-323 ◽  
pp. 873-876 ◽  
Author(s):  
Akira Todoroki ◽  
Kazuomi Omagari ◽  
Masahito Ueda
Keyword(s):  
Electrical Resistance ◽  
Cryogenic Temperature ◽  
Matrix Crack ◽  
Fuel Tank ◽  
Matrix Cracking ◽  
Resistance Change ◽  
Cfrp Laminates ◽  
Resistance Increase ◽  
Matrix Cracks ◽  
Electrical Resistance Change

For a cryogenic fuel tank of a next generation rocket, a Carbon Fiber Reinforced Plastic (CFRP) laminated composite tank is one of the key technologies. For the fuel tank made from the laminated composites, matrix cracks are significant problems that cause leak of the fuel. In the present paper, electrical resistance change method is adopted to monitor the matrix cracking of the CFRP laminate. Previous studies show that tension load in fiber direction causes electrical resistance increase due to the piezoresistivity of the carbon fibers, and fiber breakages also cause the electrical resistance increase of the CFRP laminates. In order to distinguish the electrical resistance changes due to matrix cracking from those due to the piezoresistivity and the fiber breakages, residual electrical resistance change under the complete unloading condition is employed in the present study. Experimental investigations were performed using cross-ply laminates in cryogenic temperature. As a result, it can be revealed that the residual electrical resistance change is a useful indicator for matrix crack monitoring of the cross-ply CFRP laminates.

Investigation of Eigen-Values for Matrix Cracks of Two Materials

2011 ◽  
Vol 488-489 ◽  
pp. 170-173
Author(s):  
You Tang Li ◽  
Rui Feng Wang
Keyword(s):  
Stress Field ◽  
Displacement Field ◽  
Poisson Ratio ◽  
Matrix Material ◽  
Matrix Crack ◽  
Matrix Cracks ◽  
Eigen Values

The eigen-values problem of matrix cracks is studied in this paper. The stress field and displacement field of plane matrix crack is setup at first. The eigen-equation of matrix cracks is founded on the basis of the stress field and displacement field. The factors to affect the eigen-values are discussed. The effect of shearing modulus and Poisson ratio of matrix material and attaching material on eigen-values are analyzed. The results show that the bigger shearing modulus of material should be selected for attaching material and the shearing modulus of attaching material should bigger than that of matrix material in fracture design.

A discrete crack network toolkit for Abaqus for damage and residual strength prediction of laminated composites

2016 ◽  
Vol 51 (10) ◽  
pp. 1355-1378 ◽  
Author(s):  
Xiaodong Cui ◽  
Eugene Fang ◽  
Jim Lua
Keyword(s):  
Air Force ◽  
Residual Strength ◽  
Laminated Composites ◽  
Matrix Crack ◽  
Matrix Cracking ◽  
Fiber Direction ◽  
Crack Network ◽  
Matrix Cracks ◽  
Damage Progression ◽  
Discrete Crack

The main objective of this article is to exploit a phantom paired element based discrete crack network toolkit for predicting the damage progression and residual strength of laminated composites without and with a hole under tension and compression. Both intra-ply matrix cracking and inter-ply delamination are considered under a co-simulation framework in the discrete crack network toolkit. A mesh-independent kinematic description of discrete matrix cracks is accomplished via user-defined phantom paired solid elements to capture the initiation and evolution of fiber orientation dependent matrix cracking. In-ply matrix crack initiation is realized by inserting a crack along the fiber direction when a matrix driven failure criterion is satisfied and a cohesive injection along the matrix crack interface is applied to account for energy dissipation during matrix crack opening. The delamination failure mode is characterized by applying Abaqus’ cohesive interaction at ply interfaces. The non-linear shear behavior is introduced by employing a power law based curve-fit model and the fiber failure is described using a continuum damage mechanics based model. Both the blind and recalibrated predictions are performed for specimens of three different layups under the Air Force Tech Scout 1 program. The predicted damage progression and the load displacement curves are compared with the testing results provided by the Air Force Research Laboratory.

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