In this work, experimental data and finite element analysis reveals deflection in diaphragm supporting material leading to non-linear pressure-reflection response. These results are contrary to the standard assumptions presented in literature, where modelling of deflection response in diaphragm pressure sensors is primarily carried out assuming a rigid supporting structure. An extrinsic fiber-optic Fabry–Perot pressure sensor, based on micro-electromechanical system, is developed and used to investigate optical deflection response. While the sensor is not novel, a series of experiments to validate support deflection phenomena are designed and carried out using a silicon membrane at gauge pressures from 0 to 1000 PSI in ambient temperature. The device is packaged with an industry standard stainless-steel housing typically used in plastic injection moulding. Sensor performance is compared to analytical and finite element modelling. Results suggest that the device is experiencing greater deflection than analytically predicted at pressures above 200 PSI, where a rigid support is assumed in existing literature. Based on these results, a modified analytical model is proposed to correct for this behaviour. The modified model is created through addition of a nonlinear component to an existing model, which is then fitted to the experimental data using least-square methods. Prediction of the experimental deflection results is improved from 81% error using a fixed-support analytical model to 4% error using the presented adjusted model. It is demonstrated that nonlinear effects are present and optically measurable in cases where deflection is lower than 1% of the membrane thickness. This work will aid in the implementation of high-resolution pressure sensors operating in harsh environment conditions.

在这项工作中，实验数据和有限元分析揭示了膜片支撑材料的偏转导致非线性压力反射响应。这些结果与文献中提出的标准假设相反，其中膜片压力传感器的偏转响应建模主要是在假设刚性支撑结构的情况下进行的。开发了一种基于微机电系统的外源光纤法布里-珀罗压力传感器，用于研究光学偏转响应。虽然该传感器并不新颖，但设计并使用硅膜在 0 至 1000 PSI 的表压和环境温度下进行了一系列验证支撑偏转现象的实验。该设备采用工业标准不锈钢外壳封装，通常用于注塑成型。将传感器性能与分析和有限元建模进行比较。结果表明，在超过 200 PSI 的压力下，该设备正在经历比分析预测更大的偏转，其中现有文献中假设有刚性支撑。基于这些结果，提出了一种改进的分析模型来纠正这种行为。修改后的模型是通过向现有模型添加非线性组件来创建的，然后使用最小二乘法将其拟合到实验数据中。实验挠度结果的预测从使用固定支撑分析模型的 81% 误差提高到使用所提出的调整模型的 4% 误差。结果表明，在偏转小于膜厚度的 1% 的情况下，非线性效应存在且可通过光学方式测量。这项工作将有助于实现在恶劣环境条件下运行的高分辨率压力传感器。