Replicating Field Response in a Laboratory

Research at The University of Massachusetts Lowell has been continuing on a particular category of testing involving replication of field test environment using a laboratory test. Typically, the field environment modes are different from the laboratory modes and this causes an incorrect vibration qualification test environment to be performed.

Research Assistant Brandon Zwink is working on a funded project from Sandia National Laboratories to address this very complicated and misunderstood issue related to vibration qualification tests that are conducted on a routine basis. The work Brandon is doing extends some previous work performed by Jesus Reyes Blanco in the SDASL Lab and utilizes a more insightful modal projection based approach to address this problem. Brandon is using smart modal shakers to demonstrate his latest technique to solve this complicated problem.

As Brandon said “We have been trying to address this problem a variety of different ways. With the latest approach, a Modal Amplitude Correction Map (MACM) is used to very clearly identify which laboratory modes are most important to replicate the field environment response. Our latest results have experimentally demonstrated this using four smart modal shakers to drive the laboratory test configuration and demonstrates the success with this new approach.”

This work is the subject of two papers presented at the 38^th International Modal Analysis Conference in Houston, Texas. The entire research effort is documented in Brandon’s dissertation completed in the spring of 2020. 

The test configuration studied was instrumented with over 20 PCB accelerometers and driven with four Modal Shop 2007E Mini Shakers along with LMS Test Lab as the data acquisition software.

Submitted by Dr. Peter Avitabile, PE; Structural Dynamics and Acoustic Systems Laboratory, University of Massachusetts Lowell