Marcelo Fsf De Moura | Faculdade de Engenharia da Universidade do Porto (original) (raw)

Uploads

Papers by Marcelo Fsf De Moura

Materials

In this work, the fracture behaviour of repaired honeycomb/carbon–epoxy sandwich panels under edg... more In this work, the fracture behaviour of repaired honeycomb/carbon–epoxy sandwich panels under edgewise compression and three-point bending loading was analysed. Assuming the occurrence of damage resulting from a complete perforation leading to an open hole, the followed repair strategy consists of plug filling the core hole and considering two scarf patches with an angle of 10° in order to repair the damaged skins. Experimental tests were performed on undamaged and repaired situations in order to address the alteration in the failure modes and assess the repair efficiency. It was observed that repair recovers a large part of the mechanical properties of the corresponding undamaged case. Additionally, a three-dimensional finite element analysis incorporating a mixed-mode I + II + III cohesive zone model was performed for the repaired cases. Cohesive elements were considered in the several critical regions prone to damage development. The failure modes and the resultant load–displacem...

$Research paper thumbnail of Determination of the fracture energy under mode I loading of a honeycomb/carbon-epoxy sandwich panel using the asymmetric double cantilever beam test$

Journal of Sandwich Structures & Materials

The asymmetric double cantilever beam (ADCB) test was used to measure the fracture energy of a ho... more The asymmetric double cantilever beam (ADCB) test was used to measure the fracture energy of a honeycomb/carbon-epoxy sandwich panel under mode I loading. A data reduction scheme based on equivalent crack length theory was developed for this case. The experimental Resistance-curves were obtained using exclusively data ensuing from the load-displacement curves avoiding the usual and non-rigorous crack length monitoring during the test. Furthermore, a mode partitioning methodology lying on cohesive zone modelling was adopted, aiming to estimate the fracture energy under mode I loading from the total fracture energy under mixed-mode I+II ensuing from the ADCB test. Numerical simulations of the ADCB test considering cohesive zone modelling were performed for the sake of validation of the followed procedure.

Neste trabalho apresentam-se os resultados obtidos em simulações numéricas dafuração de laminados... more Neste trabalho apresentam-se os resultados obtidos em simulações numéricas dafuração de laminados de carbono/epóxido usando elementos sólidos tridimensionais dosoftware ABAQUS® Explicit. O início e propagação do dano são simulados recorrendo ainstruções específicas do programa, bem como a remoção dos elementos ao longo doprocesso. Os resultados obtidos numericamente são comparados com resultadosexperimentais obtidos previamente pelos autores. Verifica-se uma boa concordância entre osresultados numéricos e os experimentais, confirmando a validade do modelo proposto

Fatigue & Fracture of Engineering Materials & Structures

Fracture characterization under mixed‐mode I + II loading of bi‐material bonded joints with alumi... more Fracture characterization under mixed‐mode I + II loading of bi‐material bonded joints with aluminum–carbon fiber reinforced polymer (AL‐CFRP) adherends was analyzed in this work. Five different and quite simple fracture tests were employed aiming to cover properly the complete mixed‐mode I + II range and identifying a representative energy‐based fracture criterion. A mode partitioning method lying on cohesive zone analysis was implemented, enabling the identification of strain energy mode I and mode II components for each type of test, which is relevant regarding the estimation of the energy‐based criterion defining the fracture envelope of these bi‐material joints.

$Research paper thumbnail of Prediction of the influence of several parameters on the mode I interlaminar fatigue/fracture characterization of CFRP laminates$

Mechanics of Advanced Materials and Structures, 2021

Fatigue/fracture characterization of carbon-epoxy laminates under pure mode I loading is addresse... more Fatigue/fracture characterization of carbon-epoxy laminates under pure mode I loading is addressed in this work. Double cantilever beam fatigue/fracture tests were performed to obtain the fatigue l...

Engineering Fracture Mechanics, 2015

Ciencia e Tecnologia dos Materiais

Neste trabalho e apresentada a simulacao do processo de furacao numa placa carbono/epoxidoutiliza... more Neste trabalho e apresentada a simulacao do processo de furacao numa placa carbono/epoxidoutilizando o Metodo dos Elementos Finitos - MEF. A placa e modelada considerandouma sequencia de empilhamento quasi-isotropica. O modelo utiliza elementos solidos de 6 e 8 nosdisponiveis no software ABAQUS®. Para a modelacao da ferramenta e usada a opcao "corpo rigido".Duas geometrias de ferramenta sao comparadas com os resultados do modelo numerico relativamenteao desenvolvimento de forcas axiais durante a furacao. O desenvolvimento destas forcasesta directamente relacionado com a existencia de danos na placa furada. Assim, a minimizacaodestas forcas permite reduzir o risco de ocorrencia de delaminacao, defeito que se pretende evitar.Os resultados relativos a forca necessaria para o inicio da delaminacao sao comparados commodelos analiticos ja conhecidos. Por ultimo e comparada a forma da area delaminada com osresultados do modelo. Os resultados numericos mostram uma concordância apreciavel com osobtidos experimentalmente

Proceedings of the Seventh International Conference on Computational Structures Technology

$Research paper thumbnail of Caracterização do comportamento à fractura em modo I do tecido ósseo cortical$

Composite Structures, 2015

ABSTRACT This paper presents an experimental and numerical study of the mixed-mode I–II delaminat... more ABSTRACT This paper presents an experimental and numerical study of the mixed-mode I–II delamination of unidirectional carbon/epoxy laminates. Double cantilever beam, end-notched flexure and mixed-mode bending tests were conducted in order to cover the full range of mode-mix combinations. Finite element cohesive zone models with a bilinear softening cohesive law were subsequently employed to fit experimental load–displacement curves. This required a genetic algorithm to find optimal bilinear softening parameters. Good agreement was achieved between predicted and experimental curves. Furthermore, the bilinear softening parameters showed consistent variations with the global mode-mix that could be interpreted in terms of local damage mechanisms. Nevertheless, further research is needed to define mixed-mode tractions and separations leading to a unique cohesive law.

Fracture of Nano and Engineering Materials and Structures, 2006

ABSTRACT Composite materials are excellent for aeronautical applications due to their high specif... more ABSTRACT Composite materials are excellent for aeronautical applications due to their high specific strength and stiffness. However, these materials may absorb limited amounts of energy through localized damage mechanisms without extensive plastic deformation. Different types of damage may be encountered in the impacted region, including matrix cracking, delaminations and broken fibbers. The presence of this damage is detrimental to the material performance and structural integrity of the composite structure. For example, impact damage is considered as the primary cause of in service delamination in composites giving rise to reductions of the compressive residual strength up to 60%, de Moura and Marques [1]. Therefore considerable research have been developed on impact response of composite materials, particularly to study the relationships between the composite constituent properties, the damage mechanisms and the degradation of mechanical properties due to impact, Cantwell and Morton [2].

54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2013

In this paper, natural frequencies, large deflections and failure safety factors of variable stif... more In this paper, natural frequencies, large deflections and failure safety factors of variable stiffness composite laminate (VSCL) plates with curvilinear fibers are studied. In each ply of these rectangular VSCLs, the fiber-orientation angle changes linearly with respect to the horizontal coordinate. To carry out the static and dynamic analysis of the laminates, a new p-version finite element, which follows third-order shear deformation theory, is employed. Large deflections are considered, hence, the analysis is in the non-linear regime. To predict the failure onset, Tsai-Wu criterion is used. Taking into account manufacturing restrictions regarding the fiber curvatures, natural frequencies, deflections, and failure safety factors of some VSCL plates are determined. These results are compared with natural frequencies, deflections, and failure safety factors of constant stiffness composite laminate (CSCL) plates.

$Research paper thumbnail of A numerical study on the SEN-TPB test applied to mode i wood fracture characterization$

International Journal of Solids and Structures, 2011