A Systems Engineering V-Model Approach to the Tolerance Based Redesign of a Military Terrain Vehicle Suspension

Abstract

Designing suspension systems for military terrain vehicles presents challenges due to conflicting performance requirements and demanding operational environments. This work applies a Systems Engineering V-Model approach to the tolerance-based redesign of a military terrain vehicle suspension. The project is part of the development of a new vehicle platform based on an existing prototype. The project begins with a literature review that compares suspension architectures based on key performance criteria, such as ride quality, wheel travel, ground clearance, and reliability. Based on this literature review, stakeholder needs, and user requirements, a double wishbone suspension is selected as the most suitable architecture for the new vehicle platform. To verify design requirements, a tolerance analysis is conducted to evaluate the effect of manufacturing tolerances on suspension angles, specifically camber and caster. A Python-based Kinematic model is developed to determine the effect of tolerances on the location of the suspension hardpoints. DynaTune-XL is used to simulate the suspension angles during wheel travel. The analysis shows that tolerances can be relaxed without exceeding predefined limits. Based on these insights, a redesign of the lower wishbone is made, focusing on manufacturability. The resulting redesign features a simplified geometry with a new shock absorber interface, optimized for production through sand casting followed by finishing machining. Material and process selection is done using Ansys Granta Edupack. The redesigned wishbone is verified through structural analysis using Altair SimSolid. The project demonstrates how the V-Model, commonly applied in aerospace and software development, can also effectively guide the development of suspension systems in the automotive/defense sector. In this work, the V-Model ensured full traceability from stakeholder needs and user requirements to verification, which helped translate high-level requirements into specific, verifiable suspension requirements. The introduced tolerance analysis method provided quantifiable insight into how dimensional variation in components led to variation in suspension angles during wheel travel. This demonstrated that the tolerances of the outer ball joints of the wishbones could be relaxed without exceeding predefined limits. The resulting lower wishbone redesign lays the foundation for transitioning from prototype to series production.