The core feature of the Fermat transducer lies in its aspherically focused active surface, which generally features a larger overall size compared with conventional transducers.The profile of the transducer is determined through dedicated calculation, which defines a special curved surface ensuring ultrasonic waves emitted from every point on the surface converge synchronously toward the target defect. This type of transducer is uniquely designed and optimized for specific inspection configurations.

Key components that must be inspected by non-destructive methods are often made of materials traditionally considered difficult for ultrasonic testing due to high attenuation or poor acoustic homogeneity, such as titanium and austenitic steel. Detecting defects of small size and considerable depth requires high lateral resolution. The combination of high lateral resolution, long sound paths and low operating frequencies necessitates the use of large-aperture focused transducers.

Inspection is commonly carried out across material interfaces that produce defocusing effects. To improve performance in these challenging inspection scenarios, aspherically focused transducers are specially designed to focus accurately on designated target points within specific materials through toroidal interfaces, meeting stringent inspection requirements.

Transducer Physical Object

Application Fields

        (1) Inspection of thick-walled components and inhomogeneous materials

       (2) Multi-region billet inspection

     
(3) Thick plate inspection

(4) Heavy forging inspection

(5) Nuclear vessel inspection

Technical Principles

1.Calculate the effective aspherical focusing area through planar, cylindrical or annular interfaces to achieve optimal focusing at specified positions inside the material with a given refraction angle.

2.Combining the aperture of the broadband transducer with the Fermat principle can significantly improve lateral resolution and signal-to-noise ratio.

3.This technology generally adopts the immersion pulse-echo method for inspection.

Technical Advantages

         1.Ultra-high resolution and signal-to-noise ratio

2.Adopting piezoelectric composite material technology, the beam profile is highly consistent with simulation results

3.Fermat principle enables flexible high-resolution beam focusing and scanning

Main Characteristics

1.Adopts piezoelectric composite material technology.

2.Center frequency (-6dB): 1 MHz to 10 MHz.

3.Relative bandwidth (-6dB): 60% to 90%.

4.Acoustic impedance matching: impedance matched with water. Compared with monolithic piezoelectric ceramics, it delivers superior energy transmission and outstanding electro-acoustic performance, raising the sensitivity by 10 to 50 dB.

5.Equipped with waterproof stainless steel housing and waterproof UHF connectors.

Simulation

CIVA acoustic field simulation: acoustic field distribution in water on the XZ and YZ planes respectively.

Transducer Photo Gallery