Study on Evaluation and Control of Reactive Force using Impact Test Pendulum

초록

This study examines the impact and reactive energy of helmet impact testers by comparing theoretical simulations with actual test results. Understanding and controlling material properties, such as soil and mechanical components, is crucial for optimizing performance. Given the difficulty in identifying load changes due to impact angle and contact reaction, PID control mechanisms were implemented to manage these variations. Both old and new bushing designs were analyzed, and surface roughness measurements of the second drop prevention device were compared. The second drop prevention device was improved by modifying the impactor holder bushing structure and incorporating PID control systems to reduce reaction and prevent secondary impacts. New bushing materials included MC Nylon with a friction coefficient of 0.2 and RJ4JP with a coefficient of 0.26. Testing at a 90° angle and 4.427 m/s speed showed energy increases due to impact angle deformation. Comparing theoretical and experimental data for old and new bushings revealed a 0.4° angle deformation. The new bushing, controlled for reduced contact area, demonstrated lower reactive resistance, with differences: old bushing -1,208 N, new bushing -421 N. The study highlights the need to predict and control material properties to enhance performance. Future research will continue to focus on optimizing PID control parameters to further reduce reactive resistance and improve material properties in various applications.