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In practice, since the measurement environments are usually complex, the electromagnetic interference problem has been an important issue for sensor applications, and the fiber sensor can overcome it effectively. this paper proposes a new type of vibration sensor based on fiber Bragg grating (FBG). The vibration sensor with double equal strength cantilever beams structure can further improve the measurement stability. The physical model of FBG vibration sensor was established, and the structural parameters of the double equa-strength cantilever beams were designed and optimized by finite element analysis. Both simulation and experimental tests are included in this paper to illustrate the low-frequency vibration performance of the designed vibration sensor. Among, the sensitivity of the sensor was 0.024 0 pm/(m.s-2), the natural frequency was 185 Hz, and the linearity was obtained, which further verify the stability and reliability of the sensor vibration frequency measurement. 相似文献
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井下火箭发射过程中消音层在发动机高温、高速燃气流作用下存在冲蚀损伤,会影响火箭发射安全,系统分析消音层燃气冲蚀损伤特性,对消音层的后期修复以及地下井结构优化具有重要意义。消音层冲蚀损伤是复杂的热-流体-固体多场耦合问题,以典型玻璃丝棉消音层为例,建立玻璃丝棉相变传热和烧蚀损伤数学模型;基于燃气流场数据提取与预处理、插值程序编写和有限元分析软件Abaqus用户子程序开发,搭建消音层燃气冲蚀损伤仿真平台,采用子模型技术,建立玻璃丝棉烧蚀数值仿真模型;对玻璃丝绵烧蚀过程进行仿真,并分析地下井井筒直径、燃气射流初始冲击高度及发动机建压速率3个因素对玻璃丝棉烧蚀损伤的影响;通过玻璃丝棉原理性冲蚀试验对数值仿真模型进行验证。结果表明:玻璃丝棉普遍发生烧蚀,且主要发生在回流和失稳阶段,沿地下井周向分布差异较小,沿轴向越靠近底部烧蚀越严重;减小井筒直径或增大建压速率将加剧烧蚀,增大冲击高度会减少烧蚀;试验结果显示玻璃丝棉都有一定的烧蚀,证明建立的仿真模型是正确的。 相似文献
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