The influence of dynamic soil parameters on tractive performance of off-road undercarriages

Design of optimal machines and off-road vehicles requires, among others the knowledge of dynamic interaction of the traction components with soil. Due to the lack of constitutive equation of soil, in practice the research centres worldwide use the so-called process analogues, i.e. the special test devices. These devices however are used only for static tests and are burdened with the scale error. They are also often subject to the so-called wall effect and bulldozing effect. The research conducted in The Department of Off-Road Machine and Vehicle Engineering has shown that in the dynamic interaction of traction components or working tools with soil a substantial strengthening of cohesive soils, which can cause even several times increase in their strength, which significantly changes the commonly used relationships based on static tests. In the article, the unique on the international scale test equipment developed in the Department of Off-Road Machine and Vehicle Engineering for experimental identification of dynamic soil strength parameters is shown. In addition, the initial results of the tests obtained with this device in the laboratory and in situ are presented. The practical impact of dynamic strengthening of soil are presented as opposite to the conventional methods, at the example of traction forces generated by the tracked undercarriage estimated by virtue of an undercarriage analytical model