SAE International issues critical new standard for lightweighting body panels, expert weighs in
Posted: January 8, 2024
SAE International’s Acoustical Materials Committee (AMC) recently released SAE J3130: Laboratory Measurement of Vibration Damping Properties Using Mechanical Impedance Method at the Center of a Bar.
This recommended practice provides a test procedure to measure the composite loss factor and bending stiffness properties of a system consisting of a damping material bonded to a vibrating bar which is excited at the center.
This new test is a gamechanger for noise and vibration professionals, and as described by noise and vibration expert and AMC member Pranab Saha, Ph.D., P.E., “very critical for lightweighting body panels.”
As the AMC was surveying the resources available to engineers for sound package material testing, they uncovered a crucial need for a more specific testing procedure unique to the new materials being used for the center bar.
“These test methods are not covered by ASTM, ISO, or JIS standards, which are designed more for architectural, commercial, and industrial applications,” Dr. Saha said. “This is the main reason why the AMC developed this standard.”
As manufacturers are focused on making lighter vehicles, understanding how different materials perform is a growing concern for industry.
“With the effort toward lightweighting of vehicles, car body panels are changing from steel to aluminum and even non-metallic composite materials,” Dr. Saha said. “SAE J3130 allows one to test any bar: steel, aluminum, glass, composites, and many other kinds.”
Until recently, Dr. Saha shared, the way to measure damping was the Oberst bar test method—first introduced in SAE J1637 in 1993. However, J1637 is applicable only for steel bars. Dr. Saha also mentioned that there are two other standards with similar methodology to J3130 (JIS G 0602: Vibration-damping property and ISO 16940: Glass in Building) but noted that their applications are limited to testing steel bars and glass bars, respectively.
With these limitations in mind, the AMC got to work, and through multi-year testing and balloting with representatives across industry were able to create this needed methodology.
Pranab Saha, Ph.D., P.E., is a retired Principal Consultant at Kolano and Saha Engineers, Inc. and member of the Acoustical Materials Committee, among his many other involvements as a prolific contributor to SAE International and the mobility industry at large. Dr. Saha is a Fellow of both SAE International and the Engineering Society of Detroit and is INCE Board Certified and a SAE Master Instructor. He’s the author of many technical papers as well as the book Acoustical Materials: Solving the Challenge of Vehicle Noise.