Design of a drop impact test rig for accelerometer validation for turbocharger application.

Abstract

Automotive turbochargers increase internal combustion engine power and efficiency in passenger and commercial vehicles. The vibrational characteristics need to be closely monitored during testing as it indicates the state of the turbocharger and its components. For this purpose, an accurate accelerometer is a must. This paper presents the design of a drop impact test rig for accelerometer validation. The design is based on ASTM E1876 standard and able to cover a frequency range of 0-6000 Hz. This represents a typical turbocharger operating speed of up to 120,000 rpm, with four common types of vibrational mode expected – synchronous, sub-synchronous, harmonic, and non-synchronous. Three materials have been selected for the specimen plate, namely ABS, Copper and AISI 1050 steel. The abovementioned frequency range can be satisfied by varying the specimen thickness. The drop impact test rig allows four different drop heights. Further combined with four different steel ball sizes, the magnitude of induced acceleration can be manipulated during the drop test. This drop impact test rig enables on-site accelerometer validation before any turbocharger gas stands testing, which is crucial for an accurate vibrational measurement.