A Procedure for Validating the Finite Element Model of a Piezoresistive Ceramic Pressure Sensor

The warm-up and offset stability of a low-pressure piezoresistive ceramic pressure sensor

“…1. The initial design was based on calculations using the analytical relations for the clamped diaphragm and the experiences from previous investigations [9,[11][12][13][14]18]. By considering the experimentally obtained elastic properties of the LTCC tape of 110 GPa (DuPont 951) and the average gauge factor of the thick-film resistors (ESL 3414B) of 18.5, a diameter of 26 mm for the 200-m thick diaphragm was determined for the pressure range up to 3 kPa.…”

“…The temperature distribution in the sensor structure resulting from the internal heating caused by the electric current flowing to the thick-film resistors was revealed by solving the corresponding time-dependent Poisson's equation for heat conduction [15]. The material parameters, i.e., the thermal conductivity, the mass density and the specific heat, specified in the script were obtained from the literature or evaluated empirically from our previous investigations [12,13,16,17]. (For an LTCC base a thermal conductivity of 3.3 W m −1 K −1 , a mass density of 3100 kg m −1 and a specific heat of 729 J kg −1 K −1 were used.)…”

“…From these results the resistances of the bridge resistors were calculated by using the experimentally obtained temperature coefficient of resistivity (TCR) of 365 × 10 −6 K −1 . (The TCR of the thick-film resistors ESL 3414B on a prefired LTCC substrate, considered in this case study, was obtained from the preceding measurements of the specially designed test samples already described in [6,12,13] in the temperature chamber.) Finally, the offset voltage was calculated for the resulting resistances.…”

FE analyses and prototype testing of a piezoresistive LTCC-based low-pressure sensor

“…An analysis of the influence of the sensor package, due to the mismatch of the temperature expansion coefficients (TECs) of the materials used, was carried out. The model was implemented in the finite-element (FE) code Ansys/Multiphysics 9.0, using the same modelling strategy as in our previous work [5][6].…”

“…4) with updated material parameters from [5] (supplemented with the materials' temperature characteristics). The temperature dependences of the resistivity of the unstrained thick-film resistors and the gauge coefficients were obtained from the experimental data, and specified in the model with linear temperature coefficients.…”