Modelling of cracking of the ceramic foam specimen with a central notch under the tensile load

Off-axis damage tolerance of fiber-reinforced composites for aerospace systems

“…Moreover, these results give a different perspective to the concept of damage tolerance. In fact, if along the longitudinal direction it was mainly the matrix porosity that enabled the damage tolerance by reducing the interlaminar shear strength (generally below 20 MPa) as a consequence of the lower matrix and matrix/fiber interface strengths [35,36], along the transverse direction it is the inverse: fibers, acting as pores, enabled the damage tolerance of the dense matrix characterized by strong fiber/matrix interfaces. In the context of off-axis composite strength and damage tolerance, such aging treatment was not detrimental, as well as the high matrix density and the strong interfaces.…”

Prediction of the Ceramic Foam Structure Failure Using a Detailed Finite Element Model

“…Another potential and more precise way how to estimate the strength of the open cell foam structures is to use their 3D Finite Element (FE) models based on the beam elements (representing particular struts) which can take into account the real size of the specimen, real average cell size or strut thickness, eventually also shape of the strut cross-section. Such an approach was used by several authors [5][6][7][8]. Its main advantage lays in still relatively low computational costs when assessing also bigger foam volumes since each strut is represented usually just by one or few elements.…”

“…The simplest condition for the definition of the strut failure is the stress condition defining failure of the corresponding strut when the maximum tensile stress exceeds the tensile strength σc of the material. It was shown that even this simple method provides relatively good approximations of the foam tensile strength predictions in comparison with experimental observations [5]. Nevertheless, one has to consider these predictions still as informative, since many details of the foam structure are significantly simplified or neglected.…”