Mechanical strength of porous catalyst carriers

Abstract

In order to extend our fundamental knowledge on the deformation and fracture of porous, amorphous particles under compressive and shear forces, we have developed a computer model within the framework of percolation theory. This ‘computational physics’ approach, which has been chosen especially in view of the complex nature of the fracture mechanism, would not have been feasible without parallel-computing facilities.Experimental data from Side Crushing Strength (SCS) tests on porous catalyst carriers show a wide variance in elasticity and breaking strength. We should like to find the physical parameters that determine these properties.The computer model is based on a two-dimensional network of Hooke-type springs with an eigenlength and a load limit. We have calculated the configuration of the spring network under a macroscopic strain. Individual springs that are stretched beyond a critical length break irreversibly. The implementation of the model on a Transputer network will be discussed.The stress-strain relations of an SCS test and our model show a similar behaviour. The force goes up linearly with the relative compression unless a breakage occurs. The system breaks into two main parts after one or two avalanches of breakages.KeywordsPercolation TheoryLoad LimitCritical LengthPercolation ModelMacroscopic StrainThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.