Stiffness and Progressive Damage Analysis on Random Chopped Fiber Composite Using FEM PDF Download
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Author: Yi Pan
Publisher:
ISBN:
Category : Composite materials in automobiles
Languages : en
Pages : 137
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Book Description
The need of vehicle weight reduction and fuel efficiency in the automotive industry calls for substituting traditional materials with lightweight ones. With the maturity of the preforming technologies, random chopped fiber composites have received increasing attention in recent years as replacement for traditional structural materials. In order to expand their application, accurate material characterization is required. Material properties such as effective elastic stiffness, material damage behavior, and strength are of primary interest. In this thesis, a micro-mechanics based finite element analysis method for the random chopped fiber composite is developed. In order to obtain the effective material properties of random chopped fiber composites, a modified random sequential adsorption technique is proposed to generate the representative volume element of random chopped fiber composites. In the three-dimensional representative volume element generation algorithm, a fiber is bended locally to avoid intersecting other fibers and consequently to overcome the "jamming limit" in the existing techniques. The volume fraction of a representative volume element generated by the modified random sequential adsorption is as high as that of the specimens provided by industry, which is about 35% to 40%. A homogenization scheme is applied to the finite element solution of the boundary value problem, defined in the representative volume element with proper boundary conditions, to compute the effective elastic stiffness constants of the composite. An automatic procedure based on a moving window technique is also presented to determine the proper size of the representative volume element of the random chopped fiber composite. Investigation on the damage behavior of the composite is carried out by using constituent's mechanical properties. Three damage mechanisms are considered, namely, the matrix cracking, interfacial debonding, and fiber breakage. The cohesive zone model is adopted to represent interfacial debonding. The effect of matrix cracking is accounted for by a modified von Mises yield criterion and subsequently a gradual material degradation model. Fiber breakage is modeled by a stress-based failure criterion and a sudden material degradation model. Effects of interfacial strength, critical energy release rate, and residual thermal stress on the overall performance of the composite are investigated. The results of the finite element analysis are validated by experimental data.
Author: Yi Pan
Publisher:
ISBN:
Category : Composite materials in automobiles
Languages : en
Pages : 137
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Book Description
The need of vehicle weight reduction and fuel efficiency in the automotive industry calls for substituting traditional materials with lightweight ones. With the maturity of the preforming technologies, random chopped fiber composites have received increasing attention in recent years as replacement for traditional structural materials. In order to expand their application, accurate material characterization is required. Material properties such as effective elastic stiffness, material damage behavior, and strength are of primary interest. In this thesis, a micro-mechanics based finite element analysis method for the random chopped fiber composite is developed. In order to obtain the effective material properties of random chopped fiber composites, a modified random sequential adsorption technique is proposed to generate the representative volume element of random chopped fiber composites. In the three-dimensional representative volume element generation algorithm, a fiber is bended locally to avoid intersecting other fibers and consequently to overcome the "jamming limit" in the existing techniques. The volume fraction of a representative volume element generated by the modified random sequential adsorption is as high as that of the specimens provided by industry, which is about 35% to 40%. A homogenization scheme is applied to the finite element solution of the boundary value problem, defined in the representative volume element with proper boundary conditions, to compute the effective elastic stiffness constants of the composite. An automatic procedure based on a moving window technique is also presented to determine the proper size of the representative volume element of the random chopped fiber composite. Investigation on the damage behavior of the composite is carried out by using constituent's mechanical properties. Three damage mechanisms are considered, namely, the matrix cracking, interfacial debonding, and fiber breakage. The cohesive zone model is adopted to represent interfacial debonding. The effect of matrix cracking is accounted for by a modified von Mises yield criterion and subsequently a gradual material degradation model. Fiber breakage is modeled by a stress-based failure criterion and a sudden material degradation model. Effects of interfacial strength, critical energy release rate, and residual thermal stress on the overall performance of the composite are investigated. The results of the finite element analysis are validated by experimental data.
Author: Vadim Silberschmidt
Publisher: Elsevier
ISBN: 0128222085
Category : Technology & Engineering
Languages : en
Pages : 382
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Book Description
Mechanics of Fibrous Networks covers everything there is to know about the mechanics of fibrous networks, from basic analysis of simple networks to the characterization of complex cases of deformation, loading, damage and fracture. Looking at various types of fibrous materials, the book studies their microstructural characterization, quantification of their mechanical properties, and performance at fiber and network levels. In addition, the book outlines numerical strategies for simulation, design and optimization of fibrous products. Techniques for testing the mechanical response of these materials in different loading and environmental conditions are outlined as well. This comprehensive resource will aid readers in obtaining qualitative data for various fibrous networks. In addition, it will help them develop modeling strategies and fine-tune mechanical performance fibrous networks and products by changing their microstructure to develop new products with desired properties and performance. - Discusses all the main features and characteristics of fibrous networks, including their microstructural characterization, quantification of their mechanical properties, and performance at the fiber and network level - Covers both basic analysis of simple networks as well as complex cases of deformation, loading, damage and fracture of fibrous networks - Outlines advanced numerical schemes for simulation, design and optimization of various fibrous materials
![A Progrssive [i.e. Progressive] Damage Analysis Including Delamination for Fiber Reinforced Composites PDF](https://books.google.com/books/content/images/frontcover/ckyPKVg1RWwC?fife=w80-h100)
Author: Sivom Manchiraju
Publisher:
ISBN:
Category : Fibrous composites
Languages : en
Pages : 224
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Book Description
Author: Pengfei Liu
Publisher: Elsevier
ISBN: 0323853536
Category : Technology & Engineering
Languages : en
Pages : 398
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Book Description
Damage Modeling of Composite Structures: Strength, Fracture, and Finite Element Analysis provides readers with a fundamental overview of the mechanics of composite materials, along with an outline of an array of modeling and numerical techniques used to analyze damage, failure mechanisms and safety tolerance. Strength prediction and finite element analysis of laminated composite structures are both covered, as are modeling techniques for delaminated composites under compression and shear. Viscoelastic cohesive/friction coupled model and finite element analysis for delamination analysis of composites under shear and for laminates under low-velocity impact are all covered at length. A concluding chapter discusses multiscale damage models and finite element analysis of composite structures. - Integrates intralaminar damage and interlaminar delamination under different load patterns, covering intralaminar damage constitutive models, failure criteria, damage evolution laws, and virtual crack closure techniques - Discusses numerical techniques for progressive failure analysis and modeling, as well as numerical convergence and mesh sensitivity, thus allowing for more accurate modeling - Features models and methods that can be seamlessly extended to analyze failure mechanisms and safety tolerance of composites under more complex loads, and in more extreme environments - Demonstrates applications of damage models and numerical methods
Author: Bhavani V. Sankar
Publisher: DEStech Publications, Inc
ISBN: 1605950890
Category : Technology & Engineering
Languages : en
Pages : 305
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Book Description
The fifth volume of the ASC series on advanced composites contains critical information on static and dynamic composite failure and how it is predicted and modeled using novel computational methods and micromechanical analysis.
Author: Shiguang Deng
Publisher:
ISBN: 9781267648990
Category : Composite materials
Languages : en
Pages : 129
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Book Description
Finite element modeling provides an efficient approach to simulate the mechanical behaviors of composite materials. Many finite element models were built to predict the mechanical responses of composite materials under the static loading conditions. Such static-loading models of composite materials were too modest to predict their behaviors under the dynamic loading process, say varying strain rates. In this thesis, we established both macromechanical and micromechanical finite element models to simulate the progressive damages of fiber reinforced composite materials under varying intermediate strain rates. With the application of the strain-rate-dependent composite properties, failure analysis and associated property degradations of failed composites, we were able to build a macromechanical finite element model to simulate the strain-rate-dependent mechanical behaviors of composite materials under intermediate strain rates. Through the comparison of our numerical results with experimental observations and modeling results reported in the literature, recommended values of mesh densities were presented and the correctness of our macromechanical mode was validated. The model was further developed with a multicontinuum theory (MCT). Based on the macromechanical model, a micromechanical model was developed to study the effects of a MCT-based constituent stress interactive failure criterion on the numerical results of a tensile test on a composite coupon with varying strain rates. The MCT is based on a constituent volume average procedure and was used to calculate the stress and strain states of every constituent within the composite. Based on the stress information of the constituents, associated failure criteria and degradation rules were presented for the model. By comparing the simulation results of the macromechanical and micromechanical models, we found some differences between them and further recommendations were given for modifying the present model to simulate the progressive damage dynamic responses of composite structures more precisely.
![Charactarization [sic] and Progressive Damage Analysis of Quasi-three-dimensional Composites PDF](https://books.google.com/books/content/images/frontcover/WhE6NcFU-JkC?fife=w80-h100)
Author: Liangkai Ma
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 348
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Book Description
Author: SN. Chatterjee
Publisher:
ISBN:
Category : Composite construction
Languages : en
Pages : 18
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Book Description
Laminated plate theory is widely used for elastic analysis and design of fiber composite structures. Use of the results for prediction of failure and for design of structures to avoid failure (with a margin of safety) is a more complex issue. Use of failure theories in terms of stresses or strains at a point can sometimes yield a very conservative estimate of the failure load. It is recognized that such theories, in conjunction with laminate analysis, yield an estimate of the point of damage onset (often in the matrix), but final failure usually requires progressive fiber breaks and significant load redistribution. Methods have been suggested to perform stress analyses beyond damage initiation, but they are very rarely used in practice (as compared to the use of plasticity theory for metal structures). Many progressive damage models make use of ad hoc assumptions for stiffness knockdowns. The objective of this paper is to demonstrate that damage mechanics (using a single or multiple damage parameters) can yield a set of constitutive laws, which are based on sound physical principles. It is shown that the dissipated energy density in a ply can be used as a damage parameter. Two structural problems are considered for demonstration. Results for the case of a pressure vessel are compared with those from netting analysis, a valid and widely accepted method for such designs. The second case is the problem of the "hole size effect," which is currently handled in practice by the use of semi-empirical methods and a series of tests.
Author: Timothy W. Coats
Publisher:
ISBN:
Category :
Languages : en
Pages : 44
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Book Description
Author: Wensong Yang
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 110
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Book Description
By considering the wide applications of composite materials, it is necessary to have a proper knowledge of dynamic behavior as well as static behavior reflecting the damage in composite materials. Strain rates have significant effects on dynamic behavior in composite materials when they are under dynamic loadings. In this thesis, a multiscale numerical approach with finite element code ABAQUS is developed to characterize failure criteria to express static and dynamic damage mechanisms of matrix cracking and interfacial debonding under uniaxial tensile loadings for composite materials. The random epoxy/glass composite material is investigated under three strain rates: quasi-static, intermediate and high, corresponding to 10-4, 1 and 200 s-1, respectively. A representative volume element (RVE) of a random glass fiber composite is employed to analyze microscale damage mechanisms of matrix cracking and interfacial debonding, while the associated damage variables are defined and applied in a mesoscale stiffness reduction law. The macroscopic response of the homogenized damage model is investigated using finite element analysis and validated through experiments. The random epoxy/glass composite specimens fail at a smaller strain; there is less matrix cracking but more interfacial debonding accumulated as the strain rate increases. The dynamic simulation results of stress strain response are compared with experimental tests carried out on composite specimens, and a respectable agreement between them under the low strain rate is observed. Finally, a case study of a random glass fiber composite plate containing a central hole subjected to tensile loading is performed to illustrate the applicability of the multiscale damage model.
