Investigation of Time-Dependent Forces on a Nano-Newton-Second Impulse Balance

Abstract

A torsional impulse balance has been developed as a new diagnostic tool to study fundamental physical processes in micropropulsion systems and laser-surface interactions. The impulse balance has been designed and tested with a robust calibration system to measure impulsive forces with resolution as low as several nano-Newton-seconds. The behavior of the impulse balance was thoroughly studied and characterized. A simple analytical model of the balance's motion was developed from the general equation of motion of an underdamped, harmonically oscillating system. Also, two distinct methods of analyzing the experimental data from the nanoimpulse balance have been investigated. The first method resolves the total impulse as a function of the balance's maximum deflection. The second method enables the determination of the impulse and/or force applied as a function of time from the balance's time-resolved motion.A calibration scheme employing electrostatic actuation techniques is used to experimentally validate the model and impulse measurement techniques. Report Documentation PageForm Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

Direct Impulse Measurements of Ablation Processes from Laser-Surface Interactions

“…This study involves the use of a nano-Newton-second Impulse Balance System (NIBS) [10] as a diagnostic tools for the accurate measurement of individual impulse bits for micro-device actuation and laser propulsion systems. The current NIBS has been able to resolve impulses as low as 7 nano-Newton-seconds, and as high as 150 microNewton-seconds, which has provided an acceptable range to study a number of the ablative processes.…”

Thrust Stand Mass Balance Measurements of Hybrid Motor Mass Flow (Preprint)

“…The TSMB has been designed based on the nNTS [5] and NIBS [8] systems, which measure thrust, or impulse, using a torsion pendulum that pivots around a vertical axis of rotation. A force imparted to those stands results in a horizontal displacement of the stand, which can be precisely measured using a linear variable differential transformer (LVDT).…”

Development of a Nano-Impulse Balance for Micropropulsion Systems

“…Air Force Research Laboratory (AFMC),AFRL/PRSA,10 E. Saturn Blvd.,Edwards AFB,CA,93524-7680 8. PERFORMING ORGANIZATION REPORT NUMBER…”