A Mathematical Analysis of Off-Road Vehicle to Avoid “Hang Up” and “Nose In” Failures 2019-01-0394
Professor of Mechanical Engineering, Georgia Southern University
Undergraduate Student, Mechanical Engineering Department, Georgia Southern University
This study focuses on the design of off-road vehicles to avoid “Hang Up” and “Nose In” failures with specific case study of Georgia Southern University’s SAE mini BAJA vehicle. The BAJA vehicle may encounter two distinct kinds of failure while climbing or descending terrain obstacles: “Hang Up” failure, and “Nose In” failures. Hang up failure occurs when the bottom of the chassis of the vehicle makes contact with the obstacle. This occurs after the front tires have cleared the obstacle but before the rear tires have. This mitigates the pace of the vehicle and may cause damage. Nose in failure is when the protruding front bumper or “nose” of the vehicle makes direct contact with either the ground or the obstacle. The possible ramifications of this event are much more disastrous than the Hang up failure. Nose in failure can send the vehicle into an end over end flip, or cause significant structural damage to the frame. Through a rigorous mathematical analysis of the two situations and considering the velocity to be negligible, the critical values of parameters such as, wheelbase, wheel diameter and nose length were determined and used as the boundary for the “safe zone” beyond which no failure can occur. It was found that for Hang up failure, reducing wheel base and maximizing wheel diameter led to a greater safe zone. In Nose in failure, reducing nose length and maximizing wheel diameter led to a greater safe zone. These parametric studies are presented using 3D graphics.