Lamb waves can be used to detect

Lamb waves can be used to detect

• A. Laminar type defects near the surface of a thin material
• B. Lack of fusion in the center of a thick weldment
• C. Internal voids in diffusion bonds
• D. Thickness changes in heavy plate

Answer: (A)

Lamb waves are guided plate waves that travel along thin materials, with their motion and energy distribution strongly influenced by the plate’s surfaces. Because certain Lamb-wave modes have displacement and energy concentrated near the surfaces, a laminar defect close to or at the surface disrupts the wave’s boundary conditions, causing detectable changes in arrival time, amplitude, or mode content. This makes Lamb waves particularly good at picking up laminar flaws such as delaminations or near-surface laminations in thin materials. In contrast, defects buried deep inside a thick weld, internal voids that are far from the surfaces, or simple thickness changes in heavy plates are less readily detected by these surface-sensitive, plate-bound waves and often require other inspection approaches.

Lamb waves are guided plate waves that travel along thin materials, with their motion and energy distribution strongly influenced by the plate’s surfaces. Because certain Lamb-wave modes have displacement and energy concentrated near the surfaces, a laminar defect close to or at the surface disrupts the wave’s boundary conditions, causing detectable changes in arrival time, amplitude, or mode content. This makes Lamb waves particularly good at picking up laminar flaws such as delaminations or near-surface laminations in thin materials. In contrast, defects buried deep inside a thick weld, internal voids that are far from the surfaces, or simple thickness changes in heavy plates are less readily detected by these surface-sensitive, plate-bound waves and often require other inspection approaches.