This paper describes an optical nondestructive testing technique for honeycomb composite material... more This paper describes an optical nondestructive testing technique for honeycomb composite material, which has been used as structural material in aeronautics and space transportation. The inspection of a honeycomb composite structure by the conventional NDT technique is difficult and complex. Optical NDT can give a solution about problems of previous technique. Optical NDT basically provides non-contact, whole-field inspection and easy
Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Com... more Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Common defects found in these materials are delaminations by impact damage and their presence will lead to structural weaknesses which could lead failure of the airframe structures. It is important to develop effective non-destructive testing procedures to identify these defects and increase the safety of aircraft travel. This paper describes the detection technique of impact damage defect using thermography and ESPI. The results obtained with the two techniques are compared with ultrasonic C-scan testing. The investigation shows that both imaging NDT methods are able to identify the presence of artificial defect and impact damage. The adoption of the thermography allowed significant advantages in inspection condition, and gives smaller error in quantitative estimation of defects.
Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Com... more Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Common defects found in these materials are delaminations by impact damage and their presence will lead to structural weaknesses which could lead failure of the airframe structures. It is important to develop effective non-destructive testing procedures to identify these defects and increase the safety of aircraft travel.
This paper describes an optical nondestructive testing technique for honeycomb composite material... more This paper describes an optical nondestructive testing technique for honeycomb composite material, which has been used as structural material in aeronautics and space transportation. The inspection of a honeycomb composite structure by the conventional NDT technique is difficult and complex. Optical NDT can give a solution about problems of previous technique. Optical NDT basically provides non-contact, whole-field inspection and easy interpretation. Representative techniques are X-ray, Thermography, Electronic Speckle Pattern Interferometry (ESPI), Shearography, Neutron Radiography and so on. They each have strengths and weaknesses with respect to system preparation, field application and inspection target. ESPI, ultrasonic testing and Thermography in this paper are applied to detect an artificial defect of 30 mm in diameter and an impact- induced delamination inside the honeycomb composite plate, which consists of an aluminum core and carbon fiber reinforced plate skin. Inspection...
In ultrasound excitation thermography, the injected ultrasound to an object is transformed to hea... more In ultrasound excitation thermography, the injected ultrasound to an object is transformed to heat by thermo-structure effect and internal friction. The advantage of this technique is selectively sensitive to thermally active defects. The appearance of defects, which can be visualized by thermography camera, depends strongly on the method of excitation. In preliminary studies, ultrasonic excitation horns of ultrasonic manufacturing process are widely adopted for a polymer structure. However, it is needed that these horns are modified for improving the defect detection capability. This paper proposes a new ultrasonic excitation horns with tuning fork shape in NDT of polymer material. Geometric conditions are optimized by FEA and application results by the developed horn are described and compared with those by a previous horn.
This paper describes the quantitative determination of the sizes and locations of subsurface defe... more This paper describes the quantitative determination of the sizes and locations of subsurface defects using lock-in infrared thermography. A phase (or temperature) difference between the defect area and the healthy area indicates the qualitative location and size of the defect. To accurately estimate these parameters, the shearing-phase technique has been employed, where the inspected image is shifted by a certain number of pixels to obtain a shifted image while subtraction of one image from the other gives the shearing-phase distribution. The shearing-phase distribution has maximum, minimum, and zero points that help determine quantitatively the size and location of the subsurface defect. Experimental results for a steel plate with artificial subsurface defects show good agreement with actual values.
This paper describes the application of ultrasound excited infrared thermography. In this techniq... more This paper describes the application of ultrasound excited infrared thermography. In this technique, an ultrasound wave passing through a material with mechanical discontinuity such as a crack or disband causes temperature raise of that due to internal friction or ...
The paper describes the quantitative determination of the size and the location of a subsurface d... more The paper describes the quantitative determination of the size and the location of a subsurface defect from the phase image of lock-in infrared thermography. Phase (or temperature) difference between a defect area and a sound area indicates the qualitative ...
This paper proposes the reference specimen for lock-in photo-infrared thermography. Basically, th... more This paper proposes the reference specimen for lock-in photo-infrared thermography. Basically, thermography depends on environmental disturbances, which is related to the defect detection ability of thermography system in non-destructive testing. ...
This paper describes an optical nondestructive testing technique for honeycomb composite material... more This paper describes an optical nondestructive testing technique for honeycomb composite material, which has been used as structural material in aeronautics and space transportation. The inspection of a honeycomb composite structure by the conventional NDT technique is difficult and complex. Optical NDT can give a solution about problems of previous technique. Optical NDT basically provides non-contact, whole-field inspection and easy
Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Com... more Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Common defects found in these materials are delaminations by impact damage and their presence will lead to structural weaknesses which could lead failure of the airframe structures. It is important to develop effective non-destructive testing procedures to identify these defects and increase the safety of aircraft travel. This paper describes the detection technique of impact damage defect using thermography and ESPI. The results obtained with the two techniques are compared with ultrasonic C-scan testing. The investigation shows that both imaging NDT methods are able to identify the presence of artificial defect and impact damage. The adoption of the thermography allowed significant advantages in inspection condition, and gives smaller error in quantitative estimation of defects.
Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Com... more Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Common defects found in these materials are delaminations by impact damage and their presence will lead to structural weaknesses which could lead failure of the airframe structures. It is important to develop effective non-destructive testing procedures to identify these defects and increase the safety of aircraft travel.
This paper describes an optical nondestructive testing technique for honeycomb composite material... more This paper describes an optical nondestructive testing technique for honeycomb composite material, which has been used as structural material in aeronautics and space transportation. The inspection of a honeycomb composite structure by the conventional NDT technique is difficult and complex. Optical NDT can give a solution about problems of previous technique. Optical NDT basically provides non-contact, whole-field inspection and easy interpretation. Representative techniques are X-ray, Thermography, Electronic Speckle Pattern Interferometry (ESPI), Shearography, Neutron Radiography and so on. They each have strengths and weaknesses with respect to system preparation, field application and inspection target. ESPI, ultrasonic testing and Thermography in this paper are applied to detect an artificial defect of 30 mm in diameter and an impact- induced delamination inside the honeycomb composite plate, which consists of an aluminum core and carbon fiber reinforced plate skin. Inspection...
In ultrasound excitation thermography, the injected ultrasound to an object is transformed to hea... more In ultrasound excitation thermography, the injected ultrasound to an object is transformed to heat by thermo-structure effect and internal friction. The advantage of this technique is selectively sensitive to thermally active defects. The appearance of defects, which can be visualized by thermography camera, depends strongly on the method of excitation. In preliminary studies, ultrasonic excitation horns of ultrasonic manufacturing process are widely adopted for a polymer structure. However, it is needed that these horns are modified for improving the defect detection capability. This paper proposes a new ultrasonic excitation horns with tuning fork shape in NDT of polymer material. Geometric conditions are optimized by FEA and application results by the developed horn are described and compared with those by a previous horn.
This paper describes the quantitative determination of the sizes and locations of subsurface defe... more This paper describes the quantitative determination of the sizes and locations of subsurface defects using lock-in infrared thermography. A phase (or temperature) difference between the defect area and the healthy area indicates the qualitative location and size of the defect. To accurately estimate these parameters, the shearing-phase technique has been employed, where the inspected image is shifted by a certain number of pixels to obtain a shifted image while subtraction of one image from the other gives the shearing-phase distribution. The shearing-phase distribution has maximum, minimum, and zero points that help determine quantitatively the size and location of the subsurface defect. Experimental results for a steel plate with artificial subsurface defects show good agreement with actual values.
This paper describes the application of ultrasound excited infrared thermography. In this techniq... more This paper describes the application of ultrasound excited infrared thermography. In this technique, an ultrasound wave passing through a material with mechanical discontinuity such as a crack or disband causes temperature raise of that due to internal friction or ...
The paper describes the quantitative determination of the size and the location of a subsurface d... more The paper describes the quantitative determination of the size and the location of a subsurface defect from the phase image of lock-in infrared thermography. Phase (or temperature) difference between a defect area and a sound area indicates the qualitative ...
This paper proposes the reference specimen for lock-in photo-infrared thermography. Basically, th... more This paper proposes the reference specimen for lock-in photo-infrared thermography. Basically, thermography depends on environmental disturbances, which is related to the defect detection ability of thermography system in non-destructive testing. ...
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