Thermography

Materials emit an infrared radiation whose intensity is dependent upon its absolute temperature. Use of a thermographic camera will allow isothermal contour lines to be identified. For non-destructive investigation the emissivity of a damage area will be different to that of an undamaged area. An external heat source, such as a quartz lamp flash, is used. The rate of decay of heat conduction differs from differences in local properties where damage is present. This is identified by the thermographic camera. Alternatively, electrical or mechanical energy can be applied to the part which results in thermal energy that can be identified using thermography. The advantages of this method is that it is fast, non-contact and can cover wide areas of flat and curved parts. Thermography is useful for detecting delaminations, inclusions and density changes but may not be useful in detecting microcracks or debonds that are presses together with no adhesions.