Abstract

This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method (FEM) and the discrete element method (DEM). Once a crack is detected at an element side in the FE mesh, discrete elements are generated at the nodes sharing the side and a simple DEM mechanism is considered to follow the evolution of the crack. The combination of the DEM with simple 3-noded linear triangular elements correctly captures the onset of fracture and its evolution, as shown in several examples of application in two and three dimensions.

Abstract

Este documento explica el funcionamiento de la interface de usuario del programa FEM2DEM para analizar sólidos bidimensionales utilizando el sencillo procedimiento FEM-DEM propuesto por Zarate & Oñate, ( A simple FEM–DEM technique for fracture prediction in materials and structures. Comp. Part. Mech. 2015  2: 301-314 ) que se utiliza para predecir el inicio y la propagación de fracturas .

Abstract

This document explains the operation of the user interface of the FEM2DEM program to analyse two-dimensional solids using the simple FEM-DEM procedure proposed by Zarate & Oñate [A simple FEM–DEM technique for fracture prediction in materials and structures. Comp. Part. Mech. (2015) 2: 301-314] that is used to predict the initiation and propagation of fractures .

Abstract

This paper describes a computation methodology to evaluate the ultimate strength and fracture of concrete samples and structures and its application to four typical tests of experimental laboratories of strength of materials. The tests results are compared and analysed from the experimental and numerical points of view in order to highlight the need for experimental trials to use the information derived from numerical results and, in turn, to validate that numerical models follow the behaviour and physics that occur in laboratory tests This comparison allows to explain the different mechanisms that occur throughout the experiments.

Abstract

The objectives of this work are focused on giving an answer to the problems presented in the operation of a railway bridge, using the FEM-DEM numerical technique considering static and dynamic loads. The purpose is to find out the existing breakage mechanisms in the bridge.

From a social aspect, there is concern about the possible collapse of the bridge, with the corresponding economic loss and eventually human losses; therefore, the interest and social involvement of the study has repercussions not only on the repair mechanisms that can be adopted but also on the possible revision of the calculation and design aspects in this type of works.

The FEM-DEM technique developed by Zárate et al. [1,2] has been validated in various laboratory tests [3-5]. Due to the characteristics of the problem, the technique used is an ideal tool to study the structural behaviour of the bridge from a static and dynamic point of view. Considering the reinforcing steel in the bridge is fundamental to carry out the structural analysis, which is why the implementation of this type of reinforcement in the FEM-DEM formulation is described.

The paper is organized as follows. First, the problems found in the civil works under study are described. Subsequently, a small sketch of the FEM-DEM technique is made, and the inclusion of reinforcing steel is formulated. After that, the different results of the static and dynamic studies carried out are presented.