Dynamic Transient Simulation To Predict Durability Loads From Road Load Profile Under Linear Assumptions

Durability assessment for vehicle structures requires load inputs from different road profiles. These load inputs can be in terms of force, acceleration and displacement and can be acquired from road load data. But if a program is in its early stage or lab facility is limited then acquiring these load inputs takes time and sometimes not feasible also. In this scenario, we can predict the durability load inputs from road load profile virtually using dynamic transient simulation with linear assumptions. These input scan be further used for quantitative or comparative validations of durability assessment for multiple sets of road load or design data. This paper emphasizes on the measurement of inputs for durability assessment from road load data using dynamic transient simulation with few assumptions. It involves the various steps like extracting the loads, full vehicle model setup and the critical parameters like damping coefficient, modal residual vectors and subsystem configuration.This also includes few examples where quantitative studies were done to validate the severity of RLDA loads which causes the test failures. Dynamic transient simulation gives the response of the model as a function of time based on a given time-dependent loading. The structure's response is based on set of the modes, which must first be extracted using an eigen frequency extraction procedure. Then the mode shape is excited by road load profiles and the response is recorded in terms of acceleration, force and displacement profiles based on time. This methodology helps to predict the G-loads, force or displacement profile from PG events with linear assumptions. Since linearity is involved in calculation, this method does not predict the insightful data for design validation. However, this method is extremely useful when it comes for comparative analysis or predicting the load input severity from multiple sets of RLDA. Keywords: Acceleration, Force and Displacement Profile, Modal Transient Approach, Road Load Data Acquisition