LET is a technique for defectoscopy. Defectoscopy techniques themselves are not meant to provide absolute values describing the specimen's state but indicating the risk of the presence of a defect. Therefore, the specimen is tested by a system of sensors under certain, quasi constant conditions.This book chapter describes how LET can be applied for nondestructive material parameter evaluation.

Chapter Contents:

• 6.1 Sigmometry
• 6.1.1 Introduction and motivation
• 6.1.2 Basic principle
• 6.1.3 Semianalytical and numerical calibration
• 6.1.4 Experimental validation
• 6.1.4.1 Methodology characterization
• 6.1.4.2 Conductivity measurement
• 6.1.5 Findings
• 6.2 Defectocscopy of multilayered structures
• 6.2.1 LET measurements of alucobond specimen
• 6.2.2 Forward simulations
• 6.2.3 Defect identification
• 6.2.3.1 Inverse solution strategy
• 6.2.4 Results and discussion
• 6.3 Inspection of composites
• 6.3.1 Composite material
• 6.3.2 Glass laminate aluminum reinforced epoxy (GLARE)
• 6.3.2.1 Magnetic field measurement
• 6.3.2.2 Force measurements
• 6.3.2.3 Defect localization
• 6.3.3 Carbon fiber reinforced polymer (CFRP)
• 6.3.3.1 Introduction to FRP
• 6.3.3.2 CFRP test specimens
• 6.3.3.3 Conductivity measurement
• 6.3.3.4 Measurements with CFRP samples
• 6.3.3.5 Numerical modeling of CFRP
• 6.3.3.6 LET experiments with CFRP
• 6.3.3.7 Summary
• 6.4 Defectoscopy of friction stir welding
• 6.4.1 Friction stir welding (FSW)
• 6.4.1.1 Imperfections/defects caused by FSW
• 6.4.1.2 Typical weld seam defects
• 6.4.2 FSW experiments
• 6.4.3 NDT of friction stir welds
• 6.4.4 MIECT measurements of friction stir welds
• 6.4.5 Potential applications of MIECT
• 6.4.5.1 Nondestructive defect detection of FSW
• 6.4.5.2 Material science
• 6.4.5.3 Process control and monitoring
• 6.5 Application to ferromagnetic materials

Inspec keywords: flaw detection; eddy current testing; inductive sensors

Other keywords: sensors; defect presence risk; nondestructive material parameter evaluation; quasi constant conditions; LET defectoscopy

Subjects: Nondestructive testing: eddy current testing and related techniques; Magnetic instruments and techniques; Sensing devices and transducers; Sensing and detecting devices; Electrical instruments and techniques; Materials testing