Ball impact and crack propagation - Simulations of particle compound material

Particle compounds are the combination of various sized particles with non-uniform properties and can be considered as one of the most complicated engineering materials. The properties of the particle compounds vary in large range depending upon applications, methods of manufacturing and ratios of its compositions. Even if the method of manufacturing is same, the properties may be different because of the arrangements of ingredients. The different types of engineering agglomerates and building materials, like concretes, are some examples of the particle compounds. Similarly, the proper recycling of particle compound is very important in order to utilize the valuable aggregates from the cheaper fine matrixes. The aim of this research is to study the crack initiation and propagation in the building materials of spherically shaped concrete structures under impact loadings. A 2 Dimensional Finite Element Analysis is carried out with central impact loading condition to understand the stress pattern distributions before cracking. The Discrete Element Method (DEM) is adopted for further analysis to study the crack propagation in particle compound. Concrete spheres of diameter 150 mm with properties of B35 (35 N/mm(2) compressive strength) are chosen for the representation. A sphere is geometrically easier for the analysis. The assumption can be made that after some stages of loading the cube shaped concrete will be similar to sphere after losing its edges. This paper discusses the continuum and discrete approach for the analysis of crack propagation in particle compound with reference to the concrete ball. The analysis is done with central impact loading conditions in different velocities ranges between 7.7 m/s to 39 m/s. The correlations between theoretical simulations and practical experiments are also discussed.