Dynamic analysis of 7 DOFs tracked vehicle on extremely cohesive soft soil

Abstract

This paper concerns about dynamic responses of a tracked vehicle crawling on extremely cohesive soft soil, which each side is composed of parallel two tracks. The tracked vehicle is consisted of 2 body, that is one body is tracked vehicle body, which is assumed as rigid body with 6-dof, the other body is buoyancy body. The two bodies are connected by revolute joint. In order to traveling performance of 7 DOFs vehicle, the dynamic analysis program of tracked vehicle is developed using Newmark’s method and incremental-iterative method[1-2]. The effects of road wheels on track and soil are neglected. A terra-mechanics model[3-4] of extremely cohesive soft soil is implemented in form of relationships: normal pressure to sinkage, shear resistance to shear displacement, and dynamic sinkage to shear displacement. Pressure-sinkage relationship and shear displacement-stress relationship should represent the non-linear characteristics of extremely soft soil. Especially, since the shear resistance of soft soil is very sensitive to the shear displacement, spatial distribution of shear displacement occurring at the contact area of tracks should be calculated exactly. A nonlinear dynamic analysis program is developed in FORTRAN.ody, which is assumed as rigid body with 6-dof, the other body is buoyancy body. The two bodies are connected by revolute joint. In order to traveling performance of 7 DOFs vehicle, the dynamic analysis program of tracked vehicle is developed using Newmark’s method and incremental-iterative method[1-2]. The effects of road wheels on track and soil are neglected. A terra-mechanics model[3-4] of extremely cohesive soft soil is implemented in form of relationships: normal pressure to sinkage, shear resistance to shear displacement, and dynamic sinkage to shear displacement. Pressure-sinkage relationship and shear displacement-stress relationship should represent the non-linear characteristics of extremely soft soil. Especially, since the shear resistance of soft soil is very sensitive to the shear displacement, spatial distribution of shear displacement occurring at the contact area of tracks should be calculated exactly. A nonlinear dynamic analysis program is developed in FORTRAN.