SAXS monitoring of mechanical tests

In order to gain full control on tensile and load-cycling tests, a tensile tester has been built for operation at synchrotron beamlines [50]. The control program written in Lab VIEW is continuously adapted to more complex experiments. Presently it can handle different kinds of continuous load-cycling programs that now are strictly synchronized with both the SAXS detector and a video grabber module (recording sequences of pictures of the sample with fiducial marks). 

The latest methodical development [51] is an automatic evaluation method of the video frames, by which the true macroscopic elongation of the sample can be determined with an accuracy of 3 decimals. Such high accuracy is required for thermoplastic materials that fail at low elongations ( 0.1). The method extracts the grating of the fiducial marks on the sample from the actual video image, computes the ID correlation function [52,53], and evaluates its long period . 

This result indicates a relaxation of the nanostructure while the extensometer stands still. Quantitative analysis shows that during relaxation, the extension of crystalline lamellae is increasing. Lamellae thicknesses are becoming nonuniform. The range of order is shortening. Cross-hatched lamellae are formed. 

In this section only principals can be outlined. The reason is that the instrumental requirements for combined experiments are being created presently. 

Adaptation of adjustment and plan of experiment. In order to gather the snapshots quickly, 

---