| Description |
This study covered the design, fabrication, and validation of a test fixture designed to measure the mechanical properties of vehicle seat backs. Prior to validation, static testing of four vehicle seats was performed, in part, to acquire a range of stiffness values. Seat backs were loaded with masses that represented the approximate forces from a range of dynamic loading conditions. Static results showed largely linear increases in stiffness as a function of load applied. Stiffness values ranged from 6-15 kN/m. Validation of the test fixture ensued, when five compression springs of known stiffness were tested under dynamic loading conditions. The validation test series consisted of three main objectives. First, an accurate and reliable method for calculating stiffness was determined. The results showed that calculating stiffness as a least squares linear fit through the entire compressive phase was the best method to calculate stiffness. The second objective was to determine if the vertical position on the test fixture produced the same measured spring stiffness at different testing heights. Under maximum stress, the results concluded that there was no significant difference among various testing heights. Lastly, the five compression springs were tested, producing no significant difference in the experimental measurements versus the provided values. Future testing will include a dynamic analysis with four vehicle seats. The goal is to create mechanical stiffness profiles of vehicle seats to use in dynamic simulations, allowing for an understanding of the effects of seat properties on occupant kinematics. |
