This paper presents the experimental evaluation of the Structure-Based Connectionist Network (SBCN) fault diagnostic system introduced in the preceding article (Jammu et al, 1998). For this, vibration data from two different helicopter gearboxes: OH-58A and S-61, are used. A salient feature of SBCN is its reliance on the knowledge of the gearbox structure and the type of features obtained from processed vibration signals as a substitute to training. To formulate this knowledge, approximate vibration transfer models are developed for the two gearboxes and utilized to derive the connection weights representing the influence of component faults on vibration features. The validity of the structural influences is evaluated by comparing them with those obtained from experimental RMS values. These influences are also evaluated by comparing them with the weights of a connectionist network trained through supervised learning. The results indicate general agreement between the modeled and experimentally obtained influences. The vibration data from the two gearboxes are also used to evaluate the performance of SBCN in fault diagnosis. The diagnostic results indicate that the SBCN is effective in detecting the presence of faults and isolating them within gearbox subsystems based on structural influences, but its performance is not as good in isolating faulty components, mainly due to lack of appropriate vibration features.

1.
Chin, H., 1992, Vibration Analysis of an OH-58A Main Rotor Transmission, Technical Report, Department of Mechanical Engineering, University of Massachusetts, Amherst, MA 01003.
2.
Lewicki, D. G., Decker, H. J., and Shimski, J. T., 1992, Full-Scale Transmission Testing to Evaluate Advanced Lubricants, NASA TM-105668, AVSCOM TR-91-C-035.
3.
Jammu, V. B., 1996, “Structure-Based Connectionist Network for Fault Diagnosis of Helicopter Gearboxes,” Ph.D thesis. University of Massachusetts, Amherst, MA 01003.
4.
Jammu
V. B.
,
Danai
K.
, and
Lewicki
D. G.
,
1998
, “
Structure-Based Connectionist Network for Fault Diagnosis of Helicopter Gearboxes
,”
ASME JOURNAL OF MECHANICAL DESIGN
, Vol.
120
, No.
1
, pp.
100
105
.
5.
Stewart Hughes Limited, 1986, MSDA User’s Guide, Technical Report, Southampton, UK.
This content is only available via PDF.
You do not currently have access to this content.