The finite block method: An analysis tool for structural engineers.

摘要

The Finite Block Method is introduced as an analysis tool for analyzing tension-weak discontinuous materials. Even though the finite element, boundary element, and Lagrangian finite difference methods have interface elements that allow them to model discontinuous materials, they generally do so under limitations since they were originally devised for continuous materials. In this work, the Finite Block Method is first formulated from a finite element approach to show that both methods satisfy equilibrium through the minimization of the total potential energy, and that the main difference between the two methods is in the application of the kinematic conditions. Examples of masonry arches, hunchbacked bridges, and the bearing capacity of frictional soils were analyzed to show the effectiveness and the advantages of the Finite Block Method. The Finite Block Method was shown to be capable of analyzing structures under high impact loading conditions. For the impact of a high kinetic-energy penetrator into rock-rubble overlays, the Finite Block Method was capable of modeling high strain-rates and large displacements that are associated with such loading conditions. To model the penetration process, a fragmentation model based on energy balance principles was devised and implemented. A fragment dispersion scheme was also devised to give each fragment an initial velocity based on energy that is not consumed in creating new surfaces during the fragmentation process. A computer program for finite block analysis called FBA was developed. This finite block analysis program was conceived with the idea of making it easy to use and to take full advantage of computer graphics. A graphics user interface was implemented using the HOOPS graphics systems. For future enhancement, an object oriented design of the Finite Block Method is proposed which will utilize the structural engineering concurrent software development environment that is currently being developed here at the Purdue School of Civil Engineering.