I. Overview

This test employed EconTest software for impact hammer testing and MIMO FRF testing modules to conduct modal analysis on a passenger vehicle drive shaft. Exciter method tests were performed under both free-free and constrained-end boundary conditions. The process involved: simplified modeling of the drive shaft, sensor (exciter) deployment, and result analysis to determine first-order modal parameters: natural frequency, damping ratio, and mode shape.

Test Conditions:

1. Exciter method with free-free boundary 

2. Exciter method with constrained-end boundary 

 

II. Test Equipment

No.	Equipment	Model
1	Dynamic Signal Analyzer	ECON MI-7208
2	Vibration Exciter	ECON VE-5110M
3	Force Sensor	CL-YD-331
4	Charge Amplifier	ECON MI-2004A
5	Uni-axial Accelerometer	EV1100 / PCB
6	Tri-axial Accelerometer	EV4540

 

III. Test Data & Analysis

1. Measurement Points

① Free-Free Boundary Condition
Results: Natural frequency = 321 Hz

② Constrained-End Boundary Condition
Results: Natural frequency = 242 Hz

IV. Conclusion
Comparative testing revealed:
The natural frequency measured under free-free boundary conditions (321 Hz) is 32.7% higher than under constrained-end conditions (242 Hz).