Numerical and experimental procedure for material calibration using the serial/parallel mixing theory, to analyze different composite failure modes

Granados, Joel Jurado; Martı́nez, Xavier; Nash, N.H.; Bachour, Carlos; Manolakis, Ioannis; Comer, A.J.; Capua, Daniel Di

doi:10.1080/15376494.2019.1675106

Cited by 10 publications

(3 citation statements)

References 58 publications

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“…One of these approaches is the serial-parallel mixing theory (S/P RoM) [4], which acts as a constitutive equation manager and is based on the definition of a set of compatibility equations between the composite components, usually fibre and matrix, relating their stress-strain performance. The validity of the S/P RoM to accurately characterize the composite stiffness, as well as different composite failure modes, has already been demonstrated in several references [5][6][7][8].…”

Section: Introductionmentioning

confidence: 89%

Multi-Objective Multi-Scale Optimization of Composite Structures, Application to an Aircraft Overhead Locker Made with Bio-Composites

et al. 2022

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The use of composite materials has grown exponentially in transport structures due to their weight reduction advantages, added to their capability to adapt the material properties and internal micro-structure to the requirements of the application. This flexibility allows the design of highly efficient composite structures that can reduce the environmental impact of transport, especially if the used composites are bio-based. In order to design highly efficient structures, the numerical models and tools used to predict the structural and material performance are of great importance. In the present paper, the authors propose a multi-objective, multi-scale optimization procedure aimed to obtain the best possible structure and material design for a given application. The procedure developed is applied to an aircraft secondary structure, an overhead locker, made with a sandwich laminate in which both, the skins and the core, are bio-materials. The structural multi-scale numerical model has been coupled with a Genetic Algorithm to perform the optimization of the structure design. Two optimization cases are presented. The first one consists of a single-objective optimization problem of the fibre alignment to improve the structural stiffness of the structure. The second optimization shows the advantages of using a multi-objective and multi-scale optimization approach. In this last case, the first objective function corresponds to the shelf stiffness, and the second objective function consists of minimizing the number of fibres placed in one of the woven directions, looking for a reduction in the material cost and weight. The obtained results with both optimization cases have proved the capability of the software developed to obtain an optimal design of composite structures, and the need to consider both, the macro-structural and the micro-structural configuration of the composite, in order to obtain the best possible solution. The presented approach allows to perform the optimisation of both the macro-structural and the micro-structural configurations.

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Section: Introductionmentioning

confidence: 89%

Multi-Objective Multi-Scale Optimization of Composite Structures, Application to an Aircraft Overhead Locker Made with Bio-Composites

et al. 2022

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“…The capabilities of the formulation to predict the mechanical performance of composite laminates in the linear and non-linear range, as well as the procedure required to obtain the material parameters from experimental tests, is described in [34]. There are several studies that show the capabilities of the formulation to predict different composite failures, such as delamination [24], [35], delamination due to compression [25] or open-hole failure compression [36].…”

Section: Serial-parallel Mixing Theorymentioning

confidence: 99%

Novel approach combining two homogenization procedures for the analysis of nonwoven biocomposites

Martı́nez

Bachmann

Otero

et al. 2022

Mechanics of Advanced Materials and Structures

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Composite materials with complex internal microstructures, such as the flax nonwoven bio-composite studied in this work, require advanced numerical models in order to predict their mechanical performance. Otherwise, the micro-structural interactions that take place between their components makes very difficult to obtain their mechanical properties and failure mechanisms. This paper presents a novel methodology that couples two homogenization formulations: a phenomenological one, the serial-parallel mixing theory; and a numerical multiscale procedure. The resulting methodology has a minimal computational cost, while it is capable to account for the different interactions that take place among the composite constituents. With the proposed approach, it is possible to characterize the mechanical response of nonwoven composites and to predict their structural failure. The methodology developed is applied to a flax nonwoven bio-composite manufactured and tested by the German Aerospace Center (DLR). The good results obtained from the simulation, when compared with the experimental values, allow considering the proposed procedure an excellent approach for the analysis of large structures made with complex microstructures, such as nonwoven biocomposites.

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“…The strength reduction model is based on a fatigue damage model developed previously for metals by Oller et al [163] and Barbu et al [16]. The stresses and strains of the composite constituents are calculated using the Serial/Parallel Mixing Theory (SP RoM) [145,65]. This theory is based on the definition of compatibility equations between the strain and stress tensors of the composite constituent materials.…”

Section: Residual Strength Modelsmentioning

confidence: 99%

Desarrollo e implementación de una formulación utilizando la teoría de mezclas serie/paralelo para la modelización de estructuras navales de materiales compuestos sometidas bajo cargas cíclicas

Jurado Granados

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The main goal of this thesis is the simulation of the performance of composite naval structures subjected to cyclic loads. The predicted behavior expected is the fatigue life of the composite structure, as well as the fatigue failure mechanisms. This achievement is conducted by coupling the serial/parallel mixing theory and a fatigue damage model. Consequently, the work has the following stages. In first place, a study is conducted in order to identify the failure mechanisms of composites in fatigue and how the different factors affect it, in order to propose a fatigue constitutive model for fibre and matrix. The review uses a constituent materials point of view, thus fatigue performance of fibres and resins are analyzed, as well as their role in each failure mechanisms. In addition, different variables that may affect fatigue behavior are described. Secondly, a numerical procedure for characterizing fibres and matrix is proposed, in order to predict the failure mechanisms in composites subjected to static loads. The procedure defines which experimental tests should be conducted and what material parameters are obtained from them. As a consequence, the material parameters of the constituent materials are defined, obtaining the failure of the composite by the failure of the constituent materials, without pre-defining the expected failure. The next stage is coupling the serial/parallel mixing theory and the fatigue model. The fatigue model modifies the constitutive equation of the components, while the rule of mixtures acts as a constitutive law manager. The fatigue models of fibre and matrix are characterized, assuming that the fatigue behavior of unidirectional laminates is driven by one of the constituents, in function of the loading direction. This methodology is validated for two different composite systems: a carbon epoxy cross-ply laminate and glass/polyester balanced angle-ply laminates. Finally, this numerical methodology is applied to two naval structures: a small section of a container ship and a flexible composite blade of a marine propeller. The two analyses obtain the failure mechanisms of both structures, as well as the ply or plies failing, and the corresponding constituent material causing the failure. One of the fatigue analyses is used in order to propose a simplified method capable of predicting the fatigue initiation in the structure, by only applying a quasi-static analysis. This method is based on comparing the maximum equivalent stress in the components with their SN fatigue curve. La tesis que se presenta tiene como objetivo la simulación de estructuras navales de materiales compuestos sometidas a cargas cíclicas. La simulación pretende predecir la vida a fatiga de la estructura, así como la obtención de los mecanismos de fallo que se producen. El medio por el que se pretende obtener dicho hito, es mediante el acoplamiento de la teoría de mezclas serie/paralelo y un modelo de daño de fatiga. Para ello, el trabajo sigue las siguientes fases. Primero, se ha realizado un estudio del estado del arte sobre los distintos mecanismos de fallo producidos en los materiales compuestos y su interacción entre ellos. Además, también se estudia el comportamiento de distintos tipos de refuerzo y matriz como materiales a granel sometidos a cargas cíclicas, es decir, sin reforzar o aglutinar. Esta parte sirve para conocer los mecanismos que se deben predecir y bajo qué condiciones se producen, así como identificar los factores que deben afectar al modelo de fatiga. Por último, esta primera parte realiza un esbozo del estado de arte actual en los métodos de predicción de la fatiga en materiales compuestos. En segundo lugar, se propone un procedimiento numérico para caracterizar la matriz y las fibras, con el fin de simular los distintos mecanismos de fallo de dos sistemas de materiales compuestos bajo cargas estáticas. El procedimiento propone los ensayos experimentales a realizar y qué parámetros de cada material se obtienen de ellos. Con este método, se consigue caracterizar los parámetros de los modelos constitutivos usados, sin necesidad de pre-definir el fallo del compuesto. En tercer lugar, se realiza el acople de la teoría de mezclas serie/paralelo con el modelo de fatiga. El modelo de fatiga modifica la ecuación constitutiva de los componentes, mientras que la teoría de mezclas serie/paralelo actúa de gestor de ecuaciones constitutivas. Para ello, se caracterizan los modelos de fatiga de los materiales constitutivos, asumiendo que el comportamiento a fatiga de los laminados unidireccionales está dominado por el comportamiento de unos de los componentes, en función de la dirección de carga. Dicho método se demuestra válido para dos sistemas de materiales compuestos diferentes: un laminado tipo cross-ply de carbono/epoxi, y otro de laminados de ángulos balanceados de vidrio/poliéster. Finalmente, el método se aplica a dos estructuras navales: una pequeña sección de un buque porta-contenedores y una hélice flexible. En ambas simulaciones se obtienen los diferentes mecanismos de fallo por los que falla cada una de las estructuras, así como el material componente que falla y la lámina correspondiente. Por último, el conocimiento aprendido se aprovecha para proponer un método simplificado que permita predecir la vida a fatiga de una estructura de compuesto sometida a cargas cíclicas. De esta manera, con un análisis cuasi-estático de las cargas máximas a las que se someten los materiales constituyentes y comparándolas con sus propias curvas SN, se puede verificar si la estructura presentará inicio de fallo por fatiga.

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Numerical and experimental procedure for material calibration using the serial/parallel mixing theory, to analyze different composite failure modes

Abstract: Capua (2019): Numerical and experimental procedure for material calibration using the serial/parallel mixing theory, to analyze different composite failure modes, Mechanics of Advanced Materials and Structures,

Cited by 10 publications

References 58 publications

Multi-Objective Multi-Scale Optimization of Composite Structures, Application to an Aircraft Overhead Locker Made with Bio-Composites

Multi-Objective Multi-Scale Optimization of Composite Structures, Application to an Aircraft Overhead Locker Made with Bio-Composites

Novel approach combining two homogenization procedures for the analysis of nonwoven biocomposites

Desarrollo e implementación de una formulación utilizando la teoría de mezclas serie/paralelo para la modelización de estructuras navales de materiales compuestos sometidas bajo cargas cíclicas

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