Abstract
Pulsed infrared thermal wave nondestructive evaluation has been widely used in various materials' R&D,
quality supervise, detection and evaluation. Furthermore, based on pulse infrared thermal wave thermography
experiment, a new signal analyze method called pulse phase thermography was introduced by changing the temporal
signal to frequency field through Fourier transform. The pulse signal consists of various frequencies information and
different thermal wave frequency reaches corresponding depth in the material. According to the relation of thermal
wave's frequency to conduction depth, pulse phase thermography method can detect the depth of defects. The
intuitionistic thermograph result is the phase information of each pixel in frequency field, through that the defect's size,
location can be well distinguished. In order to solve the depth detection, two standard flat bottom holes samples made of
aluminum and steel were studied. By analyzing the experimental results, it showed the theoretical depth value and actual
depth relations, which can provide an assistant way for subsurface defects detection of material and structure. In that case,
given a standard sample with artificial defects, the products made of the same material can be well detected and
evaluated. At the same time, corresponding to the pulse infrared thermal wave thermography, phase thermographs with
the phase information have higher sensitivity to the defects, and do not influence with the ununiformity of the light
heating.
