用于水果损伤检测的超声换能器

Ultrasonic Transducer Used in Fruit Damage Testing

超声检测技术是发现水果早期内部损伤的有效方法,但是由于水果普遍存在颗粒特性,高频声波在水果中衰减严重,很难实现有效穿透,无法有效进行内部无损检测。设计了一种基于PZT-4的厚圆片复合振动低频高能超声换能器。在建立PZT-4厚圆片敏感材料数学模型的基础上,分析和研究了敏感元件性能与激励条件的关系,结合试验测定的手段,优化了换能器性能,并进一步用试验验证了该换能器的实用性。该型换能器具有发射声能高、直径小的特点,能与水果曲面有效耦合,可实现对苹果、梨等水果的有效穿透,适用于内部组织破坏和皮层破裂等损伤的早期检测。

Non-destructive testing methods had attracted wide attention in recent years, and it was found that ultrasonic testing was an effective way for fruit early internal damage detection. However, the sound energy cannot easily penetrate the fruit for effective testing due to its grain characteristic of it, leading to great attenuation of sound. A multi-vibration, low frequency and high emission energy ultrasonic transducer based on PZT-4 thick wafer was thus developed in this paper. The mathematical model of the sensitive element was established, and the performances of the transducer were researched under different excitation conditions and optimized with the help of experimental testing. At last, the practicality of the transducer has been verified by further experiments. The designed transducer with high sound emission energy and small diameter achieved effective coupling with the fruit surface, well penetration to a fruit, such as apple and pear for example, for early inner damage testing.