A New Technique for Determining Bending Stiffness of Mechanical Necks 930099

The accuracy of computer model simulations of dynamic events relies on the quality of the mechanical property data sets of the systems they represent. A new technique for determining the bending stiffness of mechanical necks has been developed at the Crew Systems Directorate of the Armstrong Laboratory, Wright-Patterson Air Force Base, Ohio. The Static Neck Tester (SNT) is a test fixture that statically loads and unloads mechanical necks in flexion, extension, and lateral bending. The base of the neck is rigidly fixed while a pure bending moment is applied to the top of the neck. A torque sensor measures the resistive torque of the neck to the applied bending moment. Two rotational potentiometers measure the neck angle and a linear potentiometer measures the linear compression of the neck between the end plates. Loading and unloading flexion, extension, and lateral bending tests were conducted on Hybrid II and Hybrid III necks. Neck rotation angle, linear neck compression, neck resistive torque, and hysteresis coefficients were determined and incorporated into data sets for dynamic neck response modeling. The results of this study have demonstrated the SNT to be a repeatable, reliable, and accurate testing platform for the determination of static mechanical properties of manikin necks.