Stress transducer interpretation analysis and stability data

A semi-conductor strain gage transducer was developed for use in measuring stress in solid propellant grain rocket motors. The requirements for survival and performance are such that the sensor has direct use as a general pressure transducer especially where small size and high reliability are a requirement. The design work, gage interpretation analysis and some long-term stability results are summarized. Design of this reliable stress transducer for embedment in a solid propellant rocket motor has utilized finite element structural analysis to minimize the stress disturbance above the transducer body and to reduce diaphragm interaction with the nonlinear viscoelastic solid propellant. Minimizing the interaction between solid propellant and transducer diaphragm required that the transducer body and flexural diaphragm be much stiffer than conventional pressure transducers.