Non-destructive testing of carbon reinforced plastics by means of phase retrieval

TL;DR

This paper presents a non-destructive method using phase retrieval to inspect carbon reinforced plastics under thermal load, capturing multiple intensity measurements to detect hidden failures.

Contribution

It introduces a phase retrieval system based on spatially separated recordings and iterative algorithms for inspecting CFRP samples under thermal stress.

Findings

Successful detection of hidden failures in CFRP samples.

Effective phase recovery from intensity measurements.

Potential for non-destructive evaluation of composite materials.

Abstract

In this work, the SLM-based phase retrieval system will be used to inspect carbon reinforced plastics samples (CFRP) under applying a thermal load. For this purpose, the system is used to capture a sequence of 8 spatially separated recording planes, where the distance between subsequent planes equals 2 mm. For detecting the hidden failures two sets of intensity observations are recorded. The first set for the initial state and the second set is captured after applying the load. To recover the phase information associated with the two states, the captured intensities have been subjected to an iterative algorithm based on the method of generalized projection.