PhD Seminar Series: “Modelling of glass matrix composites by the Coupled Criterion and the Matched Asymptotics approach. The role of a single platelet”

We will continue with our Seminar Series on Thur. 18 May 2023

On site: Salón de Grados Leganés


For the next event in the Aerospace PhD Seminar Series, we will have the pleasure of hosting Sara Jiménez Alfaro researcher at Sorbonne Université

The event will take place in the Salón de Grados on Thursday 18 May at 1pm and will be streamed.

Sara Jiménez Alfaro (Seville, 1996) is a final-year PhD student at Sorbonne University (Paris).
Sara studied the Aerospace Engineering degree and then the Master in Aeronautical Engineering at University of Seville. In 2020, she was selected as a member of the international PhD network NewFrac, within the Marie Curie programme, and moved to Paris to start her PhD thesis at L’Institut Jean Le Rond d’Alembert. Since 2020, Sara has made two secondments at University of Seville, to collaborate with the Elasticity and Strength of Materials Group. She is currently doing a secondment at the Safran Tech research centre, belonging to the Safran company, until June 2023.

“Modelling of glass matrix composites by the Coupled Criterion and the Matched Asymptotics approach. The role of a single platelet”


One of the main drawbacks of glass is its very low fracture toughness, which is faced by the addition of a second constituent. An example is the borosilicate glass/Al 2 O 3 platelet composite, in which alumina platelets are embedded in a glass matrix. According to literature, different toughening mechanisms were experimentally observed, some of them related to a change in the crack path. Therefore, the aim of this work is to study the effect of such toughening mechanisms, considering the role of a single platelet. In Fig. 1 a scheme of the problem is shown. It can be observed that the dimensions of the platelet are much smaller than the ones of the specimen. For this reason, special emphasis is put in the analysis of the size effect. In experiments the length of the platelet is However, a huge range is considered in this study. For each value of the so-called apparent fracture toughness of the composite, is obtained through the application of the Coupled Criterion (CC). Moreover, Matched Asymptotic Expansions with respect to d are used to reduce the excessive mesh refinement due to the smallness of the platelet, in comparison with the dimensions of the specimen. In addition, they allow a single calculation whatever the platelet size.
One of the main conclusions obtained in this study is the size effect observed in the problem. For very short platelets the failure is produced due a lack of available energy in the platelet, i.e. the energy condition is governing the failure. Moreover, if the size of the platelet is small enough the crack propagation is unstable, joining the glass region beyond the platelet, whereas for long platelets the crack has a stable growth, and the crack increment remains inside the platelet, or along the interface glass/alumina. Furthermore, a study of the influence of alumina fracture properties has been made, from which it can be concluded that has a greater effect than.

The seminars will begin at 1pm and will take place in the Auditorium Salón de Grados (Padre Soler
No previous registration is required.

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