Distortion-free single point imaging of multi-layered composite sandwich panel structures

Area of Science:

• Materials Science
• Medical Imaging
• Aerospace Engineering

Background:

• Aluminum honeycomb sandwich panels are crucial composite materials in aerospace.
• These structures can interfere with Magnetic Resonance Imaging (MRI) by distorting magnetic fields (B0 and B1).
• Assessing the integrity of composite materials non-destructively is vital for safety and maintenance.

Purpose of the Study:

• To investigate the effects of an aluminum honeycomb sandwich panel on MRI fields (B0 and B1).
• To evaluate the impact of these distortions on image quality.
• To explore advanced imaging techniques for overcoming these challenges and enabling defect detection.

Main Methods:

• Magnetic Resonance Imaging (MRI) was used to analyze the effects of the sandwich panel.
• Single point (constant time) imaging techniques were employed.
• A new mathematical expression was derived to quantify gradient field distortion errors.

Main Results:

• The sandwich panel structure was found to distort the B0 field and attenuate the B1 field.
• Distortion-free imaging was achieved using single point imaging techniques.
• The graphite-epoxy skin of the panel was identified as the primary source of B0 distortion.
• The derived error expression did not result in geometric image distortion.

Conclusions:

• Despite magnetic field distortions caused by aluminum honeycomb sandwich panels, distortion-free MRI is feasible with advanced techniques.
• The graphite-epoxy composite material is the main cause of B0 distortion.
• These findings support the development of MRI-based methods for detecting moisture ingress and degradation in composite structures.