Defense, Armor Plates

(b) Flaw Detection in Ceramic Armor Plates

Detection of Cracks and Delamination

The Resonance Ultrasonic Vibrations (RUV) technology was developed for non-destructive detection of cracks and delamination in composite ceramics used in body armor plates. The RUV technology implements fast measurement of the ultrasonic resonance response in ceramic substrates. Invisible peripheral or bulk cracks or delaminated components are exhibited as deviation of the resonance response between the flawed plate and a standard plate. In addition, the RUV tool allows “health” monitoring of the individual plate integrity during routine maintenance and rotation.

Ceramic substrates used to manufacture armor plates are the primary contributors to the overall performance of the finished product. Quality controls, in regard to cracks and delamination, as well as process controls in production, are two primary aspects that require advanced testing efforts. To ensure that armor plates are not damaged and adhere to performance standards, periodic quality inspection is a mandatory requirement for armor plates employed in combat and special operations as well as after storage, shipping and transportation. Commercially available the RUV-CP.1 model is used in plate production, while RUV-DBAM model is a deployable portable system.

RUV technology provides

  1. Within seconds non-destructive inspection of mechanical flaws (cracks, delamination) during plate production
  2. Detection of these mechanical flaws in fully assembled plates after deployment during periodic quality inspections in the field
  3. Cost-effective solution to quality control and maintenance service.

Additionally, the RUV system serves as a process improvement tool that increases yield by eliminating production flaws caused by mechanical defects.

Frequency Curve

Through a resonance frequency curve selected from a broad range (20 - 250 kHz) the RUV method enables delamination detection in ceramic armor plates with simple quantitative criteria. A crack introduced into ceramic substrate alters RUV peak parameters: bandwidth and peak position. This is illustrated in Figure (left plot) by comparing RUV curves measured on four standard SAPI plates with the identical plate rejected due to internal crack. Specifically, the crack in the plate shows the following features: (1) a frequency shift of the peak position, and (2) an increase of the peak bandwidth.

A delamination of armor plate components alters RUV peak parameters: amplitude, bandwidth and peak position. This is illustrated in Figure (right plot) by comparing RUV curves measured on standard plates with the identical plate inspected by CT scan with confirmed delamination. Specifically, a delaminated plate shows split of a primary broad peak on multiple sharp lines. This feature is automatically revealed by RUV software. The RUV approach is based on fast measurement and analysis of a specific resonance peak and rejection of the suspect sample if peak characteristics deviate from similar non-cracked samples. Black lines are good plates, red line is a delaminated plate.

Within seconds non-destructive inspection of mechanical flaws cracked during plate production
Within seconds non-destructive inspection of mechanical flaws delaminated during plate production

The RUV method to inspect delamination is based on a statistical approach. In case studies, the capture rate of RUV method approaches 100%.

For more information, please contact us through the Ultrasonic Technologies website.