Laboratory Measurement of Vibration Damping Properties Using Mechanical Impedance Method at the Center of a Bar
Develop a test methodology to measure the damping performance of a composite or other bar from the frequency response function obtained from the excitation force and the corresponding acceleration level, both measured at the same point.
Rationale: This recommended practice discusses a test methodology to measure composite loss factor of a damped bar, where the Oberst bar damping test method (SAE J1637) is not a suitable test method in many applications, where the vibrating panel are not made out of steel, or they cannot be excited efficiently. In addition to the composite loss factor, this method also computes the bending rigidity ratio of a damped test bar by exciting the bar at the center using a shaker and an impedance head. This methodology is often called CenterPointe method. This methodology is often called the CenterPointe method. Currently there are no SAE standards for this type of test.