Theoretical and experimental analysis of the soil pressure and wear distribution on plough

Soil engaging tools are subjected to durability problems due to particularly severe wear. During ploughing work wear is generated by the interaction between tillage tool and soil. There are several wear modes on tillage tools, but the predominant cause of material loss is due to the abrasive action of soil particles. Wear rate is strongly affected by soil-tool pressure distribution and it compromises plough performances during its life cycle. The aim of this PhD thesis is the development of a test methodology able to measure and evaluate the pressure distribution on a working plough body using tactile sensors. Field tests were performed with a 4 furrows reversible plough by Gruppo Nardi attached to a New Holland T7.260 tractor and tested at different soils, speeds and ploughing depths. Tractor speed and the horizontal force at the hitch points of the plough were measured. The pressure mean value is influenced both by speed and depth, but each part of the plough has its own characteristic behaviour. The pressure signals demonstrated to be spiky, in fact the pressure mean value was lower than 1% of the maximum value for up to 92% of the ploughed distance. Moreover, spike patterns are markedly affected by the speed especially in terms of the number of spikes and their distribution. The methodology and the results introduced in this PhD thesis will be useful for the validation of mathematical models to simulate the ploughing process, reducing the time required for the engineering design process of optimized ploughs. A possible future development of this research activity is the design of accelerated tests in order to permit a fast validation of plough bodies.