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The traditional role of the test lab has been to subject prototype products or components to carefully defined programs and evaluate acceptability from the viewpoint of vibration, stress, durability, life, noise, safety, reliability, performance, etc. If a product or component fails prescribed test criteria, it is sent back for rework by an appropriate designer. The test engineer seldom works with or meets the designer, except when “crisis” type problems are encountered. Computer Aided Engineering (CAE) already has had a dramatic effect on drafting, design analysis, and testing groups. Mini-computer based testing systems, using modal analysis and animated mode shape test capabilities were introduced into the test lab in the early 1970's. Many new tools and techniques have become available since then. These later tools have a revolutionary impact on mechanical product development and the role of mechanical test engineers in the development process.

Structural Dynamics Research Corporation has been involved in the development and application of advanced testing and analysis techniques for improving the vibration performance of vehicles for over ten years. Techniques such as narrow band spectrum analysis, modal testing, and building block simulation have been the topic of several technical papers, 1,2,3,4,5,6 and have been widely accepted by the automotive industry as useful techniques for vehicle vibration improvement. In this paper, the authors describe a new method of application of modal analysis and building block technology which has been made possible by advances in minicomputer software. Examples of recent projects performed by SDRC* are described, which illustrate how a test engineer can identify and evaluate various fixes to a vehicle vibration problem utilizing a minicomputer based hardware-software system in his laboratory.