Introducción a un novedoso método para detectar grietas en base a materiales piezoeléctricos y piezorresistivos.
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Date
2025
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Publisher
Universidad de Concepción
Abstract
El campo del monitoreo de salud estructural ha estado en apogeo desde principios del nuevo milenio, dentro de este tema, la detección de grietas es primordial para saber el estado de una estructura determinada y proyectar su tiempo de vida. Por otro lado, los materiales piezoeléctricos se han ocupado con gran fiabilidad en otros aspectos, como lo son sonares, micrófonos, parlantes, equipos médicos, circuitos, defensa, entre otros, desde el principio del siglo XX. Para lo que son grietas, han demostrado tener varias aplicaciones, como lo son los sensores de acústicos, vibracionales y transductores. Mientras que, por otro lado, los materiales piezorresistentes, como el Velostat, se han ido expandiendo hace pocos años en el ámbito de sensores, por ejemplo, las mediciones de masa o empuje. En efecto, este proyecto aborda si es posible detectar grietas estructurales usando materiales piezoeléctricos y piezorresistentes, donde se fabricó un sensor con 70% de su peso total en material piezoeléctrico y 30% en matriz de epoxi, el cual al ser sometido a pruebas de impacto entregó un voltaje de respuesta de hasta 7.2 [𝜇𝑉]. Mientras que, al ser expuesto a vibraciones, demostró dar una respuesta con una frecuencia igual a la de excitación y a una amplitud dependiente a la aceleración que está sometida. De la misma forma, se validó el sensor piezoeléctrico para la detección de grietas realizando diversos ensayos de fatiga, donde se obtuvieron señales de hasta 66 [𝜇𝑉] para cuando este se terminaba de romper. Con respecto a los sensores piezorresistentes, se demostró que su incremento en resistencia eléctrica es directamente proporcional a la propagación de la grieta, y se puede asociar la aparición de una grieta cuando hay un 60% de aumento en su resistencia eléctrica con respecto a su valor inicial. Como conclusión, se puede validar nuevas formas de detección de grietas mediante el uso de materiales piezoeléctricos y piezorresistivos. En base a la innovación sobre los métodos actuales, el desarrollo y aplicación de una metodología sólida, y la caracterización de estas nuevas formas de detección mediante ensayos de impacto, fatiga y vibración.
The field of structural health monitoring has been increasingly growing since the turn of the millennium. Among the topics that involve this field, the detection of cracks has been primordial to diagnose the state of a given structure and estimate its remaining life. Among other things, piezoelectric materials have been used widely and with good reliability in other topics, like sonar, microphones, speakers, medical instruments, circuits, defense, among others, since the start of the XX century. For crack detection, piezoelectric has been used as acoustic sensors, vibration sensors and transducers. While piezoresistive materials, such as Velostat, have been having a surge on different sensing applications these last couple of years, for example, mass and force measurement. In effect, this project reviews if it is possible to detect cracks through the usage of piezoelectric and piezoresistive materials, where a sensor made up of 70% of total weight as piezoelectric material and 30% epoxy, demonstrated signals up to 7.2 [𝜇𝑉] under impact testing. While, when exposed to vibrations, its signal displayed a response with frequency equal to the source of the excitation and an amplitude closely related to the acceleration of said vibration. Likewise, the piezoelectric sensor was validated as a crack detector through a series of fatigue tests that showed signals up to 66 [𝜇𝑉] at moments when the sensor itself cracked. Meanwhile, for piezoresistive based sensors, it was demonstrated that its electric resistance was directly proportional to the crack growth, and it was possible to associate the appearance of the crack when the sensor registered a 60% increase over its initial reads. As a conclusion, it has been possible to validate the new ways of crack detection for piezoelectric and piezoresistive materials. This was based on innovative solutions over already existing ones, the development and implementation of a solid methodology, and the characterization of these new forms of detections using impact, fatigue and vibration tests.
The field of structural health monitoring has been increasingly growing since the turn of the millennium. Among the topics that involve this field, the detection of cracks has been primordial to diagnose the state of a given structure and estimate its remaining life. Among other things, piezoelectric materials have been used widely and with good reliability in other topics, like sonar, microphones, speakers, medical instruments, circuits, defense, among others, since the start of the XX century. For crack detection, piezoelectric has been used as acoustic sensors, vibration sensors and transducers. While piezoresistive materials, such as Velostat, have been having a surge on different sensing applications these last couple of years, for example, mass and force measurement. In effect, this project reviews if it is possible to detect cracks through the usage of piezoelectric and piezoresistive materials, where a sensor made up of 70% of total weight as piezoelectric material and 30% epoxy, demonstrated signals up to 7.2 [𝜇𝑉] under impact testing. While, when exposed to vibrations, its signal displayed a response with frequency equal to the source of the excitation and an amplitude closely related to the acceleration of said vibration. Likewise, the piezoelectric sensor was validated as a crack detector through a series of fatigue tests that showed signals up to 66 [𝜇𝑉] at moments when the sensor itself cracked. Meanwhile, for piezoresistive based sensors, it was demonstrated that its electric resistance was directly proportional to the crack growth, and it was possible to associate the appearance of the crack when the sensor registered a 60% increase over its initial reads. As a conclusion, it has been possible to validate the new ways of crack detection for piezoelectric and piezoresistive materials. This was based on innovative solutions over already existing ones, the development and implementation of a solid methodology, and the characterization of these new forms of detections using impact, fatigue and vibration tests.
Description
Tesis presentada para optar al título de Ingeniero Civil Aeroespacial
Keywords
Monitoreo de salud estructural, Fatiga de materiales, Piezoelectricidad