# 4927 / Tip Angle Dependence For Resistive Force Into Dry Granular Materials At Shallow Cone Penetration ## Authors Naoki Iikawa and Hiroaki Katsuragi {% hint style="info" %} Paper presented at ISTVS 2024 | 21st International and 12th Asia-Pacific Regional Conference of the ISTVS\ Keywords: Granular materials; Discrete Element Simulation; Stress analysis; Shallow penetration\ {% endhint %} ## Abstract In relation to the interaction of the earth's surface with machines and organisms and its engineering applications, there has been a recent increase in interest in the penetration resistive force into granular materials at shallow depths. Recent studies have proposed the model in which penetration resistive forces into dry granular materials have a coefficient dependent on the angle of repose and increase in proportion to the penetration volume. In these studies, the model has been validated for various geometries such as cylinders, cones and spheres. However, for cones, the model has only been validated under conditions of a tip angle close to the angle of repose. In this study, the effect of cone tip angle on penetration resistive force is investigated under several conditions with different angles of repose. This study carries out cone penetration simulations using the discrete element method. For the cone geometry, this study prepares five tip angles ranging from sharp to blunt. The results show that the penetration resistive force for cones with blunt tip angles is much higher than that computed by the model proposed in previous studies. To solve the discrepancy between the model and simulation results, this study modifies the penetration volume by assuming that the stagnant zone formed in front of the cone penetrating the granular material behaves as an effective cone. Thereby, the proposed model can calculate penetration resistive forces more accurately for cones with a wider range of tip angles than in the previous model. *** Full paper purchase: \ ISTVS members receive three complimentary papers per year: --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://2024.istvs.org/submissions/papers/4927.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.