Contactless Sensor/Actuator Method for Regular Health Monitoring of CFRP Structures

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Technology abstract

System for contactless damage measurement in fiber components. Cost effective method for monitoring the structural integrity of CFRP structures without touching the hardware. Micro-technology implanted in the structure for self-control from fabrication to test to deployment - with RFID technology, electroactive polymers, carbon nanotubes (CNTs), fiber optics and piezo-ceramic vibration control sensors.

 

Technology Description

Spacecraft only work with the intelligence they give you on their way into space. Here, a micro-technology implanted directly in the structure is used to self-control production from test to use - with RFID technology, electroactive polymers, carbon nanotubes (CNT), fiber optics and with piezo-ceramic sensors for vibration control.
The technology is based on a combination of RFID and piezo actuation and sensing technology.

Due to the flexible and flat design, the RFID sensor actuator can be easily integrated into fiber reinforced structures during the molding process or later.

The sensor / actuator patches provide: 

  • wireless data transfer
  • wireless energy energy transfer 
  • sensing and actuation of ultrasonic waves 

With this combination it is possible to investigate the actual status of the material and to transmit this information wireless to an external system.
For the detection of fatigue effects, impacts or damage, such as microcracks or delamination, which  cannot be detected with naked eye, several technologies have already been invented and developed.  Examples or ultrasonic, X‐ray, externally attached piezo‐ceramics. But all of these methods need a  high effort in handling of large tools over a large surface. Or cables are disturbing the measurement  procedure or are decreasing the performance of the structure. In aerospace, or e.g. in the print  industry, the maintenance of specific items via RFID‐tags is already in use. This method has been patented.

Innovations & Advantages

The novelty is the combination of both for the process:

1) Energy is transmitted wireless into the piezo element via a lightweight handheld tool 
2) After ignition of the piezo element via handheld and RFID tag, a shock wave is transmitted  through the structure. 
3) These waves are receipted by another piezo‐element identified by the connected RFID tag. 
4) These information will be submitted again back to the handheld 
5) Data evaluation can be performed at a separate work station or automatically. 

The detection of failures are based on calibration of the structures and a data base.

Current and Potential Domains of Application

The technology achieves its highest benefit in structures, which are subject to very long life cycles such as in

  • aerospace,
  • automotive and
  • wind energy sector.

Continuous maintenance and technical  checks are necessary in order to avoid major failures up to catastrophic events.

A cost effective method for the health monitoring enables a quick control of the structure without lengthy attachments of cables or measurement systems. Due to the contactless nature of this technology and the easy identification of the sensor actuators the technology has high potentials in cost savings compared to present wired solutions.