[PDF] Progressive Damage And Failure Model For Composite Laminates Under Multiaxial Loading Conditions eBook

Author : Peter Amaya
Publisher :
Page : 239 pages
File Size : 13,21 MB
Release : 2012
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ISBN :

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Abstract: A progressive damage and failure model is proposed for continuous fiber reinforced composite laminates under triaxial loading conditions. A literature review with emphasis on macromechanics based failure theories applied to composite laminates under static loading conditions shows that there is a need to validate failure models for composite laminates under triaxial loading conditions. Available experimental data show that the mechanical behavior and progressive damage of composite laminates may be different under multiaxial loading than under uniaxial loading conditions. The proposed failure model is an extension of the strain energy failure theory for triaxial loading conditions. The proposed strain energy model requires six parameters in order to predict the mechanical behavior and progressive damage of a composite laminate. Three material parameters are determined through laboratory tests involving unidirectional laminates subjected to multiaxial loading or multidirectional laminates subjected to uniaxial loading. The remaining three model parameters are used to represent unloading of failed lamina after initial failure has occurred. The proposed strain energy based failure theory and post initial-failure degradation model are combined with a stress field developed using either classical lamination theory or the finite element method using reduced integration quadratic hexahedral elements. The proposed failure model with classical lamination theory stress field gave adequate predictions compared with published experimental results for the initial failure, progressive damage, and final failure for tubular specimens under combined torsion and hydrostatic pressure as well as cylindrical dogbone specimens under combined uniaxial loading and hydrostatic pressure. The proposed failure model with the finite element stress field was able to adequately model stress concentrations near the free edges as well as predict initial, intermediate, and final failures for a cross-ply coupon under uniaxial extension as compared with experimental data. The validation of the proposed model suggests that it may be extended to predict the progressive damage and failure of composite laminate structures of complex geometries under complex loading conditions.

Author : Ashith P. K. Joseph
Publisher :
Page : 114 pages
File Size : 49,52 MB
Release : 2017
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Composite materials are widely used in various industries for making structural parts due to higher strength to weight ratio, better fatigue life, corrosion resistance and material property tailorability. To fully exploit the capability of composites, it is required to know the load carrying capacity of the parts made of them. Unlike metals, composites are orthotropic in nature and fails in a complex manner under various loading conditions which makes it a hard problem to analyze. Lack of reliable and efficient failure analysis tools for composites have led industries to rely more on coupon and component level testing to estimate the design space. Due to the complex failure mechanisms, composite materials require a very large number of coupon level tests to fully characterize the behavior. This makes the entire testing process very time consuming and costly. The alternative is to use virtual testing tools which can predict the complex failure mechanisms accurately. This reduces the cost only to it’s associated computational expenses making significant savings. Some of the most desired features in a virtual testing tool are – (1) Accurate representation of failure mechanism: Failure progression predicted by the virtual tool must be same as those observed in experiments. A tool has to be assessed based on the mechanisms it can capture. (2) Computational efficiency: The greatest advantages of a virtual tools are the savings in time and money and hence computational efficiency is one of the most needed features. (3) Applicability to a wide range of problems: Structural parts are subjected to a variety of loading conditions including static, dynamic and fatigue conditions. A good virtual testing tool should be able to make good predictions for all these different loading conditions. The aim of this PhD thesis is to develop a computational tool which can model the progressive failure of composite laminates under different quasi-static loading conditions. The analysis tool is validated by comparing the simulations against experiments for a selected number of quasi-static loading cases.

Author : Gerardo I. Arboleda Gonzalez
Publisher :
Page : 164 pages
File Size : 21,17 MB
Release : 2021
Category : Electronic dissertations
ISBN :

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A composite payload attach fitting (PAF) is being designed and fabricated at NASA MSFC for the Block 1B heavy-lift Space Launch System (SLS).Functioning as the primary structural interface, the PAF is connected to the payload by metal clevis fittings via pin connections.The overall goal of this study was to develop a reliable FE based methodology to analyze the pinned joints of composite honeycomb panels and determine their load-carrying capacities.This goal has been achieved by the following: (1) development of two-dimensional progressive damage models of composite panels for various failure modes, (2) experimental determination of the necessary parameters for the progressive failure models, (3) incorporation of the developed composite failure models into an FE-based algorithm to analyze the damage progression of composite laminates under pin bearing loading conditions and to determine the load carrying capacity of pinned joints of composite honeycomb sandwich panels, and (4) validation of the developed failure models via experiments. Carbon/epoxy unidirectional tape and eight-harness fabric were used for this investigation. At the coupon-level tests, the basic mechanical properties and the material degradation parameters were obtained. Multi-axial loaded tests served as a validation exercise for the damage models.The finite element analyses were conducted using a commercial FE software package Abaqus in conjunction with a user material subroutine written in Fortran. The pin-bearing specimens tested at WSU as well as test data provided by MSFC were used for the final validation of the developed material model. From the results comparison, the FE model with the developed material model was able to predict the maximum pin-bearing capacity of composite panels, and the in-plane deformations showed satisfactory correlation between the FE models and the experiments.

Author : Shiguang Deng
Publisher :
Page : 129 pages
File Size : 49,87 MB
Release : 2012
Category : Composite materials
ISBN : 9781267648990

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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.

Author : Ramesh Talreja
Publisher : Elsevier
Page : 620 pages
File Size : 25,15 MB
Release : 2023-09-29
Category : Technology & Engineering
ISBN : 0443184887

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Modeling Damage, Fatigue and Failure of Composite Materials, Second Edition provides the latest research in the field of composite materials, an area that has attracted a wealth of research, with significant interest in the areas of damage, fatigue, and failure. The book is fully updated, and is a comprehensive source of physics-based models for the analysis of progressive and critical failure phenomena in composite materials. It focuses on materials modeling while also reviewing treatments for analyzing failure in composite structures. Sections review damage development in composite materials such as generic damage and damage accumulation in textile composites and under multiaxial loading. Part Two focuses on the modeling of failure mechanisms in composite materials, with attention given to fiber/matrix cracking and debonding, compression failure, and delamination fracture. Final sections examine the modeling of damage and materials response in composite materials, including micro-level and multi-scale approaches, the failure analysis of composite materials and joints, and the applications of predictive failure models. Provides a comprehensive source of physics-based models for the analysis of progressive and critical failure phenomena in composite materials Assesses failure and life prediction in composite materials Discusses the applications of predictive failure models such as computational approaches to failure analysis Covers further developments in computational analyses and experimental techniques, along with new applications in aerospace, automotive, and energy (wind turbine blades) fields Covers delamination and thermoplastic-based composites

Author : Jerry Zhigi Wang
Publisher :
Page : 256 pages
File Size : 47,11 MB
Release : 1993
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ISBN :

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An experimental study of strength and failure behavior of orthotropic G-10 glass fiber reinforced composite laminates in an in-plane stress state has been conducted. Different types of biaxial specimens and associated test fixtures were developed and employed in the study. Standard IITRI specimens were used to determine tensile and compressive failure strengths of G-10 composite laminates in both fill and warp directions. Biaxial tension-compression (BTC) and biaxial compression-compression (BCC) flat coupon specimens with flexible end reinforcements were designed and tested to study failure behaviors and mechanisms of composite laminates under a biaxial tension-compression and biaxial compression-compression stress states. Tubular specimens loaded in axial tension, axial compression, torsion, internal pressure, and external pressure were employed to produce desired combinations of in-plane stresses and strains. Based on the biaxial failure envelopes obtained from the tests, notched BCC specimens (BCC(n)) were tested in a biaxial compression loading condition to study failure behavior of notched laminates under a biaxial stress state. Failure mechanisms of notched and unnotched composite laminates have been studied based on the test data and failure surface examination.

Author : Bryan Harris
Publisher : Elsevier
Page : 765 pages
File Size : 35,9 MB
Release : 2003-10-31
Category : Technology & Engineering
ISBN : 1855738570

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This major handbook is the first authoritative survey of current knowledge of fatigue behaviour of composites. It deals in detail with a wide range of problems met by designers in the automotive, marine and structural engineering industries. Compiled from the contributions of some of the best-known researchers in the field, it provides an invaluable, practical and encyclopaedic handbook covering recent developments. Comprehensively discusses the problems of fatigue in composites met by designers in the aerospace, marine and structural engineering industries Provides a general introduction on fatigue in composites before reviewing current research on micromechanical aspects Analyses various types of composites with respect to fatigue behaviour and testing and provides in-depth coverage of life-prediction models for constant variable stresses