EXPERIMENTAL STUDY AND NUMERICAL MODELLING FOR FLEXURAL CAPACITY OF FRC STRUCTURAL ELEMENTS

Concrete reinforced by short steel fibres is typical brittle matrix composite, in which fibres are impeding cracks growth, such way increasing material’s tensile strength. The use of steel fibre reinforced concrete (SFRC) in structures with high physical and mechanical characteristics makes possible to reduce their weight and cost, to simplify their production technology, to reduce or eliminate reinforcement labour, at the same time increasing reliability and durability. Randomly distributed discontinuous fibres are bridging the crack’s flanks providing material’s “ductility”- like non-linear behaviour at cracking stage. The current study is focused on one formulation of a specific type of concrete matrix with added fibres and without fibres. Concrete cubes and prisms without fibres and having in every situation the same content of 60 mm long fibres were fabricated. Cubes (100×100×100 mm) were tested in compression and beams (100×100×400 mm prisms) were tested under four-point bending (4PBT). Fracture process (crack growth) in the material was modelled, based on experimental results (part of experimental data was used). Finite element method (FEM) using the ANSYS program analysis were realized modelling stress distributions in the broken beams with the goal to predict fracture process. Model’s prediction was validated.

Impact Response of Composites

As fiber-reinforced polymeric composites continue to be used in more damage-prone environments, it is necessary to understand the response of these materials when subjected to impact from foreign objects. This chapter provides an overview of the analysis methods for impact-damaged composites. It discusses the causes and effects of various failure mechanisms in composite materials. The failure mechanisms covered are brittle-matrix composite failure, tough-matrix composite failure, thermoplastic-matrix composite failure mechanisms, untoughened thermoset-matrix composite failure mechanisms, toughened thermoset-matrix composite failure mechanisms, particle interlayer-toughened composite failure mechanisms, and dispersed-phase, rubber-toughened thermoset-matrix composite failure mechanisms.

A New Anisotropic Damage Model for Ceramic Matrix Composites

Within the framework of irreversible thermodynamics, a new general constitutive model for describing damage and its effect on the overall properties of anisotropic solids is proposed. The ability of the model to describe the overall stress-strain response as well as the loss of symmetry resulting from the interaction between initial and damage-induced anisotropy in a brittle matrix composite is demonstrated.