Soil Energy Absorption During The Collision Of A Zero-turn Radius Lawn Mower With Soil

In recent years, with the increasing of the amount of the mower, it often can be caused to the rollover accidents and bring a great risk to the operaters. If the deformation of the soil is smaller when the mower is in contact with the unsaturated soil, the rolling energy of the mower will be higher and vice versa. Therefore, it is of great significance to carry out the research on the anti-impact characteristics of the unsaturated soil, that is, the deformation and energy absorption.Based on the analysis of the deformation characteristics of the soil under the impact process and three simple constitutive models(elastic model, plastic model and viscous model), the relation process of unsaturated soil under impact loading is divided into four stages to analyze and study and the dynamic model of four stages are established,the dynamic equation of each working stage is obtained.According to the soil test method standard GB/T 50123-1999, the unsaturated soil used to the impact test is needed to be sampled and prepared. Some physical parameters are also measured(including: soil density,moisture content) and particle size analysis. Finally, the relevant theoretical formula is derived to verify that the non-saturation values of the samples collected in this experiment can meet the experimental requirements.The soil stress-strain gauge is designed and manufactured in this paper, the force sensor and angle sensor are used to collect the force deformation curve of the corresponding collision process. At the same time, by adjusting the initial angle of the pendulum in the three cases, respectively 30 degrees,40 degrees,50 degrees to study the different load conditions of soil deformation characteristics and make an experimental study. The force deformation curves under various conditions are acquired and the absorbed energy of the whole process is calculated. Then the experimental data under the various conditions is compared with the theoretical model results and analyzed to verify the correctness of the theoretical model.The deformation energy under the collision of the mower is calculated by the validated theoretical model and then using the energy conservation formula to calculate the kinetic energy of the mower in theory. Compared with the actual value of the kinetic energy, it is concluded that there is a trend of continuous rolling. Therefore, based on the security considerations, the height of the rolling protective structure and the weight of the deck are improved in this paper, then rolling test is carried out in a golf training base in Yangzhou. The test shows that the mower with the improved structure do not have a continuous roll, which verifies the effectiveness and feasibility of the theoretical model(constitutive model).