A Micromechanics-based Independent Mode Failure Criterion for Fiber-reinforced Composites PDF Download
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Author: Yŏng-bae Cho
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 276
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Book Description
Author: Yŏng-bae Cho
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 276
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Book Description
Author: P. K. Gotsis
Publisher:
ISBN:
Category :
Languages : en
Pages : 20
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Book Description
Author: M. Hinton
Publisher: Elsevier
ISBN: 0080531571
Category : Technology & Engineering
Languages : en
Pages : 1269
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Book Description
Fiber reinforced polymer composites are an extremely broad and versatile class of material.Their high strength coupled with lightweight leads to their use wherever structural efficiency is at a premium. Applications can be found in aircraft, process plants, sporting goods and military equipment. However they are heterogeneous in construction and antisotropic, which makes making strength prediction extremely difficult especially compared to that of a metal. This book brings together the results of a 12year worldwide failure exercise encompassing 19 theories in a single volume. Each contributor describes their own theory and employs it to solve 14 challenging problems. The accuracy of predictions and the performance of the theories are assessed and recommendations made on the uses of the theories in engineering design.All the necessary information is provided for the methodology to be readily employed for validating and benchmarking new theories as they emerge.Brings together 19 failure theories, with many application examples.Compares the leading failure theories with one another and with experimental dataFailure to apply these theories could result in potentially unsafe designs or over design.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 96
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Book Description
This research has focused on limit behavior of fiber composites with granular matrices (such as fiber reinforced soils). Dominant mechanisms of fiber matrix interaction were identified. Mathematical description of the behavior of granular composites on the macroscale was presented based on microstructural interactions. The concept of mathematical homogenization was introduced to represent the failure properties of the composite on the macroscale. Failure criteria for composites both with fibers in a preferred direction and with randomly distributed fibers were derived. A Laboratory technique was devised for preparation of the specimens of fiber reinforced composites. Experimental test were carried out, and the experimental evidence was collected for validation of the mathematical description. Implementation of the derived criteria in numerical methods for solving boundary value problems was presented.
Author: Anastasios P. Vassilopoulos
Publisher: Springer Science & Business Media
ISBN: 1849961816
Category : Technology & Engineering
Languages : en
Pages : 246
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Book Description
Fatigue has long been recognized as a mechanism that can provoke catastrophic material failure in structural applications and researchers are now turning to the development of prediction tools in order to reduce the cost of determining design criteria for any new material. Fatigue of Fiber-reinforced Composites explains these highly scientific subjects in a simple yet thorough way. Fatigue behavior of fiber-reinforced composite materials and structural components is described through the presentation of numerous experimental results. Many examples help the reader to visualize the failure modes of laminated composite materials and structural adhesively bonded joints. Theoretical models, based on these experimental data, are demonstrated and their capacity for fatigue life modeling and prediction is thoroughly assessed. Fatigue of Fiber-reinforced Composites gives the reader the opportunity to learn about methods for modeling the fatigue behavior of fiber-reinforced composites, about statistical analysis of experimental data, and about theories for life prediction under loading patterns that produce multiaxial fatigue stress states. The authors combine these theories to establish a complete design process that is able to predict fatigue life of fiber-reinforced composites under multiaxial, variable amplitude stress states. A classic design methodology is presented for demonstration and theoretical predictions are compared to experimental data from typical material systems used in the wind turbine rotor blade industry. Fatigue of Fiber-reinforced Composites also presents novel computational methods for modeling fatigue behavior of composite materials, such as artificial neural networks and genetic programming, as a promising alternative to the conventional methods. It is an ideal source of information for researchers and graduate students in mechanical engineering, civil engineering and materials science.
Author: M. W. Hyer
Publisher: DEStech Publications, Inc
ISBN: 193207886X
Category : Technology & Engineering
Languages : en
Pages : 718
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Book Description
Updated and improved, Stress Analysis of Fiber-Reinforced Composite Materials, Hyer's work remains the definitive introduction to the use of mechanics to understand stresses in composites caused by deformations, loading, and temperature changes. In contrast to a materials science approach, Hyer emphasizes the micromechanics of stress and deformation for composite material analysis. The book provides invaluable analytic tools for students and engineers seeking to understand composite properties and failure limits. A key feature is a series of analytic problems continuing throughout the text, starting from relatively simple problems, which are built up step-by-step with accompanying calculations. The problem series uses the same material properties, so the impact of the elastic and thermal expansion properties for a single-layer of FR material on the stress, strains, elastic properties, thermal expansion and failure stress of cross-ply and angle-ply symmetric and unsymmetric laminates can be evaluated. The book shows how thermally induced stresses and strains due to curing, add to or subtract from those due to applied loads.Another important element, and one unique to this book, is an emphasis on the difference between specifying the applied loads, i.e., force and moment results, often the case in practice, versus specifying strains and curvatures and determining the subsequent stresses and force and moment results. This represents a fundamental distinction in solid mechanics.
Author: Dean Curtis Foster
Publisher:
ISBN: 9780549954064
Category : Composite materials
Languages : en
Pages : 511
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Book Description
The present work has identified two competing failure initiation mechanisms occurring in a unidirectional model composite system when loaded transverse to the direction of the fibers. Matrix cavitation and fiber-matrix debonding are the failure modes that have manifested themselves as a function of fiber spacing in multi-fiber cruciform specimens. The model composite system used two transparent epoxy systems, a linear room temperature cured 828/D-230 system and a nonlinear high temperature cured 862/W system, with five 0.36 mm diameter stainless steel wires as fibers. The fibers were arranged such that a single fiber was placed at the intersection of the face diagonals of four fibers located at the corners of a square. Seven different fiber spacing groups were tested ranging in volume fraction from 64% to 4%. Failure initiation was optically detected in-situ via the reflected light method using multiple high resolution, high magnification microscope video cameras. Three dimensional (3-D) finite element models (FEM) for all fiber spacing groups tested were used to analyze the stress state in the cruciform specimen at failure initiation. Residual stresses of both epoxy systems were measured by photoelasticity methods for incorporation into the micromechanical FEM. Analytical results of the individual cruciform 3-D FEMs in conjunction with the experimental observations were used to evaluate fiber-matrix debond and matrix failure criteria. A linear interaction debond criterion expressed as the sum of the ratios of the interfacial normal stress to tensile strength and interfacial shear stress to shear strength best validated the observed debond limits at the fiber spacing exhibiting fiber-matrix debonding as failure initiation. For the matrix failure criterion, analytical results indicated that the Mohr-Coulomb criterion validated the fiber spacing exhibiting cavitation. This work has developed failure criteria that correctly identified the two competing failure initiation modes that occurred as a result of the varying internal stress state as a function of fiber spacing. The criteria accurately predicted the observed debonding limits and matrix cavitation of both matrix systems. The detailed understanding and findings of this work will assist the materials engineer by increasing the fidelity of composite solutions to meet the increasing aerospace structural demands.
Author: Chandra Sekher Yerramalli
Publisher:
ISBN:
Category :
Languages : en
Pages : 582
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Book Description
Author: Yi Wu
Publisher:
ISBN:
Category :
Languages : en
Pages : 183
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Book Description
The primary objective of this research work is to investigate the effective mechanical responses of continuous fiber reinforced composites by modifying and extending the available micromechanical framework. A major part of the work conducted involves the investigation of the effective damage responses due to damage evolutions of matrix microcracks and fiber breakages. Chapter 3 presents the effective elastic damage behavior of continuous fiber reinforced composites with evolutionary matrix microcracks. A cohesive penny-shape microcrack model is proposed within a two-step homogenization framework to achieve the effective elastic damage behavior of continuous fiber reinforced composites. In the proposed model, the size and the number density of microcracks are defined as two damage parameters to control the matrix microcrack evolution. In addition, the thermal effect is taken into account by taking advantage of the thermal eigenstrain and the Eshelby's equivalent inclusion principle. The overall coefficient of thermal expansion (CTE) of the composite is systematically derived under the framework of micromechanics to describe the overall damage behavior of composites due to matrix microcrack evolution under temperature changes. Chapter 4 proposes a micromechanical evolutionary damage framework capable of predicting the overall mechanical behavior of and damage evolution in continuous fiber reinforced composites. In the framework, the effective stress fields in a single fiber due to an embedded penny-shaped fiber breakage are systematically derived by applying the double-inclusion theory. The notion of effective length denoting the distance between two adjacent breakages is introduced as a damage parameter while determining the damage evolution within a single fiber. This enables the modeling of the effective damage behavior of a single-fiber reinforced composite. As an application of the proposed framework, a micromechanical damage model is further proposed to simulate the fiber-dominated failure mechanism within a multi-fiber composite. A Weibull probability function is adopted to estimate the varying volume fractions of damaged fibers and intact fibers. Numerical simulations are presented to demonstrate the effectiveness of the proposed methodology. In Chapter 5, based on the linear elastic fracture mechanics (LEFM) and ensemble-volume averaging technique, an effective eigenstrain is newly proposed to quantify the homogenized stress fields in a single fiber due to multiple fiber breakages. In the proposed model, the number density evolution of fiber breakages is characterized by a two-parameter Weibull statistic with the temperature effect implicitly enclosed by properly adjusting the Weibull parameters. The damage criterion in the evolutionary damage model is theoretically derived. Utilization of the proposed damage framework, a homogeneous damage evolution model capable of simulating the material behavior of multi-fiber reinforced composite materials is developed. Chapter 6 presents two stochastic risk-competing models to simulate the fiber breakage evolution in a multi-fiber composite with an inhomogeneous fashion by considering different load sharing mechanisms. A unit cell model is adopted with each cell being assigned an initial weakness based on a normal distribution. Damage evolution inside each cell structure follows the micromechanical model presented in Chapter 5. Two risk-competing models are introduced subsequently to determine the damage sequence within the multi-fiber composite by computing the fracture probability based on the weakness of cells at each time step. It is observed that one risk-competing model tends to generate a concentrated damage pattern with broken fibers clustering in a T-shape or a cross-shape, while the other model yields a more diffused damage pattern. Finally, the overall stress-strain responses and the fiber breakage evolution are predicted and verified against experimental data. Chapter 7 examines the effective elastoplastic behavior of metal matrix composites (MMCs) containing unidirectionally aligned continuous fibers. A homogenization procedure is utilized to derive the overall yield function for the composite based on the probabilistic spatial distribution of aligned inclusions. Based on continuum plasticity, a plastic flow rule and a hardening law are postulated. These laws together with the proposed overall yield function then characterized the macroscopic elastoplastic behavior of the composite under three-dimensional arbitrary loading/unloading histories. The overall uniaxial elastoplastic stress-strain behavior of MMCs with aligned continuous fibers is investigated. Comparisons between theoretical predictions and experimental data for the composite are performed to illustrate the capability of the proposed method. Chapter 8 concludes the present research on micromechanics and effective elastic and elastoplastic behavior of continuous fiber reinforced MMCs. Finally, related future research topics are discussed briefly.
Author: Anthony M. Waas
Publisher: DEStech Publications, Inc
ISBN: 1605950882
Category : Technology & Engineering
Languages : en
Pages : 282
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Book Description
The fourth 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.
