Method development for estimating deflection and fatigue life using flex body-based vibration fatigue

Author: Ajit Wandhare Co-Author: Prasad Kulkarni Abstract: The structural analysis of off-highway machine platforms has traditionally relied on inertial loads and single-point excitation-based vibration fatigue methods, derived from earlier testing. While these approaches provide qualitative insights, they often lead to either under- or over-designed components, resulting in the need for multiple physical builds to address issues related to platform deflection and lifespan. Furthermore, handrail deflection assessments have historically been subjective, allowing for potential inaccuracies in problem identification. This paper investigates the implementation of flex body-based estimation techniques for predicting deflections in both platforms and handrails, as demonstrated in a deflection estimation exercise for a current off-highway machine platform. This innovative methodology enhances the precision of deflection and life predictions during the mule or feasibility stages, enabling timely corrective actions that significantly reduce costs in the later phases of the Product Development Process (PDP). By adopting this advanced analytical approach, the need for extensive physical builds can be minimized, leading to more efficient and accurate designs. This work underscores the potential for improved design outcomes and cost savings in the development of off-highway machinery. Key topics included in this paper are: • Development of methods for accurate deflection prediction • Correlation between Test results and flex body-based FE estimations for deflection (> 90%) and fatigue life (1x to 5X) • High confidence in FEA predictions before accelerated design verification (ADV) test to replicate the behavior of platform and handrails • Business impact and overall product development efficiency improvements