# Research on Alternating Current Field Measurement Method for Buried Defects of Titanium Alloy Aircraft Skin

## TL;DR

This paper introduces a new method using alternating current field measurement to detect hidden cracks in titanium alloy aircraft skins.

## Contribution

A detection probe based on alternating current field measurement is designed and optimized for detecting buried defects in titanium alloys.

## Key findings

- The probe can detect small cracks as short as 3 mm and as deep as 2 mm in titanium alloy plates.
- Simulation and experiments confirm the probe's high sensitivity to varying defect lengths and depths.
- The method is feasible for detecting buried defects in thin-walled titanium alloy aircraft skins.

## Abstract

Titanium alloys are extensively used in the manufacturing of key components in aerospace engines and aircraft structures due to their excellent properties. However, aircraft skins in harsh operating environments are subjected to long-term corrosion and pressure concentrations, which can lead to the formation of cracks and other defects. In this paper, a detection probe is designed based on the principle of alternating current field measurement, which can effectively detect both surface and buried defects in thin-walled titanium alloy plates. A finite element simulation model of alternating current field measurement detection for buried defects in thin-walled TC4 titanium alloy plates is established using COMSOL 5.6 software. The influence of defect length, depth, and excitation frequency on the characteristic signals is investigated, and the detection probe is optimized. Simulation and experimental results demonstrate that the proposed detection probe exhibits high detection sensitivity to varying lengths and depths of buried defects, and can detect small cracks with a length of 3 mm and a burial depth of 2 mm, as well as deep defects with a length of 10 mm and a burial depth of 4 mm. The feasibility of this probe for detecting buried defects in titanium alloy aircraft skin is confirmed.