The paper presents theoretical, experimental and numerical studies on the thermal behavior of mineral wool used in sandwich panels. The aim of this study is to investigate the thermal properties of mineral wool at elevated temperatures and provide a simple model that would allow us to determine the heat propagation in sandwich panels during a fire. The paper proposes a new method to experimentally evaluate thermal diffusivity, derived from theoretical premises. Experiments are conducted in a laboratory furnace where specimens are placed and temperatures inside specimens are measured. Different methods are used to process the test results and calculate the thermal diffusivity of mineral wool. Finally, a numerical analysis of heat transfer using the finite element method (FEM) is performed to validate the obtained thermal properties.

The paper presents theoretical, experimental and numerical studies on the thermal behavior of mineral wool used in sandwich panels. The aim of this study is to investigate the thermal properties of mineral wool at elevated temperatures and provide a simple model that would allow to determine the heat propagation in sandwich panels during fire. The paper proposes a new method to experimentally evaluate thermal diffusivity, derived from theoretical premises. Experiments are conducted in a laboratory furnace, where specimens are placed and temperatures inside specimens are measured. Different methods are used to process the test results and calculate the thermal diffusivity of mineral wool. Finally, a numerical analysis of heat transfer using finite element method (FEM) is performed to validate the obtained thermal properties.

The study focuses on calibrating a system for inductive heating of samples before performing dynamic compression tests using a Split Hopkinson Pressure Bar (SHPB). In the proposed set-up, the crucial role is played by the pyrometer, which could continuously control the temperature of the specimen during the test. The coupling of the experimental test together with numerical simulations (including thermal and mechanical simulations) is performed to calibrate the considered system. The key outcomes of the coupled experiment and simulation analyses are the shortest heating time required to achieve a uniform temperature in the neck of the sample and the change in the temperature field during cooling (after the heating ends). This procedure will also be used in real experiments to predict the temperature sensitivity of the material under dynamic compression under precisely controlled thermal conditions for a temperature range of 250 °C to 730 °C.

The paper presents a comparison of three strain measurement methods. The mechanical parameters of S355 grade steel (yield strength, tensile strength, modulus of elasticity) were determined in tensile tests. Strains were measured using high resolution measuring instruments: an extensometer, a strain gauge and an ARAMIS 3D DIC system. In this paper, these three instruments have been used simultaneously in tensile tests for the first time. The results indicate that the values of the Young’s modulus obtained using different techniques were similar when each instrument measured strain on the same side of the sample. Small differences were connected with different gauge lengths and their locations. The values of the Young’s modulus determined on the opposite sides of the samples were more varied even when the same method was used (strain gauge measurements). For this reason, it is recommended to use double-sided averaging instruments when the Young’s modulus is determined. The strain-curves obtained from the strain gauge measurements were incomplete and they came to an end at the end of the yield plateau due to the fact that they were damaged when the values of strain were relatively high. The extensometer was used up to the point where the strain reached 0.3% and then the strain was measured based on the distance between the machine clamps. The stress-strain curves obtained from the DIC system were complete because the system was able to monitor the sample until the very end of the tests.