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Thermoelastic stress analysis (TSA) is a powerful technique to measure the temperature changes induced in a cyclically loaded material. For a quantitative analysis of the strain field from the measured temperature change a calibration of the measured TSA-signal is necessary. In the calibration of the fibre-reinforced materials, the anisotropic and inhomogeneous nature of the material has to be taken into account. The measured TSA-signal is usually provided in camera units (CUs). To calibrate the thermoelastic signal against the material's physical properties, a temperature calibration of the TSA-signal has to be performed. This is achieved using DeltaVision software by assigning the measured CUs to a temperature value, taking the infrared sensor's non-linear response into account.A calibration is conducted against a measurement on uniaxially loaded specimens with respect to the observed material's microstructure and its resulting mechanical and thermoelastic properties. The calibration constant evaluated is compared with a calibration against the material's physical properties and applied to a component under a working load.From the measurement results, it appears that the influence of the middle stress predicted by the higher-order theory of the thermoelastic effect is significant for the investigated material.

Open cell aluminum foam core sandwich panel structures have been proven to be of interest for protecting satellites against micrometeoroids and orbital debris (MMOD). Bumpers containing aluminum foam show outstanding capabilities to induce multiple shocks to small projectiles in the hypervelocity regime. For this work the protective performance of foam cored sandwich panels with cores made from newly developed hybrid metal foams was evaluated. Therefore shots in the hypervelocity regime on the two-stage light gas gun of the French-German Research Institute of Saint-Louis were performed. The tested targets were sandwich panels with aluminum front and rear facesheets and cores of different types of metallic foams: foams with pore densities of 10 pores per inch and 45 pores per inch were tested as pure aluminum and hybrid metallic foams. The projectiles to simulate micrometeoroids and orbital debris were aluminum spheres with a diameter of 4mm. The impact velocity was 6500m/s. It could be shown experimentally that the nickel coating of the aluminum foams leads to a decreased crater depth in the sandwich panels. However, scatter in the coating thickness leads to variations in the foam densities of the hybrid foams, making the evaluation of the increase in the protective performance difficult. Nevertheless, due to the nickel coating the influence of the pore density seems to be more significant than reported before. By reducing the coating thickness and using high performance aluminum alloys as base material for the hybrid foams, further optimization of the protective performance could be reached. Then, the complete evaluation of the ballistic limit over a broad velocity regime should be done to see the variations in the performance of the hybrid foams over the whole velocity range being of interest for MMOD shielding technologies

Processing of long-fibre reinforced thermoplastics with a discontinuous reinforcement of long glass fibres, especially by direct-processing, leads to inhomogeneous and anisotropic properties. Because of this, locally resolved characterisation of the material properties is necessary. Non-contact testing methods are required to derive these material properties. Locally resolving hysteresis measurement, full-field strain measurement techniques and thermoelastic stress analysis (TSA) are applied to an incremental step test and to a fatigue test. It is shown that there is good correspondence between the local TSA-signals and the locally measured values of the major strain. This correlation is valid not only for lower linear elastic load levels, but also up to nonlinear-viscoelastic levels. A model is presented to describe the correlation between the TSA-signal and the measured major strain.

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