Abstract
A share-point is a cutting edge of the ploughshare, the crucial component of a horizontally reversible plough (HRP). Our previous trials in sandy loam soil indicated that severe abrasion/attrition wear with white materials appeared at the share-point section in the high-speed shifting tillage operation of the HRP. This mechanical fatigue was demonstrated to be caused by the flowing soil-tool interaction. But whether the white materials are associated with the thermal effects due to the high-speed tillage is not known. This paper extended our previous work to evaluate the thermal effects by using a combined multi-body dynamics analysis (MDA) and fluid-solid-thermal simulation. The dynamic interaction between soil and share-point was studied with the MDA approach. Based on the generated tillage forces through the MDA, a fluid-solid-thermal model of the ploughshare was developed to investigate the specific quantitative results, maximum stresses and temperatures observed at the share-point, which were further compared with the published worn-lands at the same tillage conditions (such as tillage speed and depth). The comparisons showed that the maximum coupled stresses and tillage temperatures in this study both appeared at the share-point, particularly at the most severe abrasion/attrition section with white materials, and that they were both varied with the different working conditions or the different tillage behaviours. Our findings demonstrate that the high-speed shifting operation of HRP has the thermal effects on the share-point wear due to the fact that the greatly varied tillage temperatures can accelerate to impact the surface integrity because of the thermal stresses detrimental to the micro-shape or size shape at the share-point section. This result may add to the knowledge base usefully applicable to the design of the high-speed mouldboard.