A Strain-Gauge Type Artificial Mastoid

Abstract

An artificial mastoid for testing bone conduction receivers is described. It consists essentially of a stiff metal bar which has a fundamental resonant frequency above the measurement range, with a strain-sensitive translating element fastened to the under side and a compliant pad on top. The translating element is a slab of activated ceramic, which is essentially invariant to humidity and temperature changes. The compliant pad generally used is Koroseal No. 74, which simulates the flesh over the mastoid prominence reasonably well. Koroseal No. 15 simulates flesh better but is less rugged. Calibration methods are discussed.

A Miniaturized Artificial Mastoid Using a Skull Simulator

“…For a long time now, repeated attempts have been made to design an artificial mastoid which could be manufactured in accordance with the mechanical properties of the skull, with long-term stability, high reproducibility, and at reasonable cost; see, for example, Carlisle & Mundel (1944), Carlisle & Pearson (1951), Weiss (1960), Stisen & Dahm (1969). Also, the mechanical properties of the mastoid portion of the skull with skin and underlying tissue have been thoroughly investigated.…”