Dynamic Analysis of Soil -Tool Interaction in Hydraulic Excavation
A Thesis Submitted to the School of Postgraduate Studies, University of Lagos.
This work improves upon earlier work in the literature concerning the motion of an excavator blade cutting through a medium with a flat surface. In particular, it involves the development of a robust analytical scheme for determining the motion of the various links of the excavator based on the geometrical parameters of the excavator and the transmitted and cutting forces of the excavator bucket. Furthermore, the scheme which involves the use of rigid body dynamics with analytical geometry and circular functions provides a generalized model from which the effect of various geometrical parameters on the cutting force for excavation can be captured in different scenarios. The study also examines the behaviour of the cutting force both in free swing and also when cutting through a medium with mitigating parameters of density, shear, cohesion and adhesion. Our model can also predict the volume of scooped material as well as the resulting bucket trajectory. As part of the validation exercise, simulations were carried out using MATLAB software in studying the various effects of the identified parameters in the excavation of granulated material such as dry sand. Use of the results obtained from our analysis can serve as a basis for enhancement of design parameters in the search for optimized excavation. Keywords: dynamic analysis, soil-tool interaction, hydraulic excavation, cutting force.