NDE of microstructured materials by x-ray diffraction and refraction topography
For the purpose of micro structural characterization X-ray topography reveals the spatially resolved scattering of materials and small components. It combines the advantages of radiographic imaging and the analytical information of wide and small angle X-ray scattering like phase distribution, texture, micro cracks, interfaces and pores. Scanning techniques at selected scattering conditions permit the topographic characterization of any crystalline or amorphous solid or liquid. Topographic methods and applications for the purposes of research, quality control and damage evaluation are presented.
Röntgentopie der Faser-und Polymerorientierung
Elastic modules and strength of composites are mainly determined by their fibre and matrix orientation. These are non-destructively measured by new X-ray topography methods in order to predict mechanical properties. The principles of the X-ray scattering methods of high spatial resolution are described. The correlations of orientation parameters with mechanical properties of injection moulding components are demonstrated.
An ultrasonic‐acoustic technique for nondestructive evaluation of fiber composite quality
This report describes an ultrasonic-acoustic technique used to measure a “stress wave factor” in order to nondestructively assess the quality of composite structures. In a prior study this factor was found effective in evaluating the interlaminar shear strength of fiber-reinforced composites. Details of the method used to measure the stress wave factor are described. In addition, frequency spectra of the stress waves are analyzed in order to indicate the nature of the wave phenomena involved. The stress wave factor can be measured with simple contact probes requiring only one-side access to a part. This is beneficial in nondestructive evaluations because the waves can run parallel to fiber directions and thus, in many cases, measure material properties in directions assumed by actual loads. Moreover, the technique can be applied where conventional through transmission techniques are impractical or where more quantitative data are required. The stress wave factor was measured for a series of graphite polyimide composite panels and results obtained are compared with through transmission immersion ultrasonic scans.