HERIe software for quantitative assessment of risk of physical damage to cultural objects due to climatic variations implemented on the on-line platform herie.pl
Acoustic emission (EA) is a non-destructive method of tracing fracturing progress in a material subjected to deformation or internal stress. The method is based on monitoring the mechanical energy released in the form of elastic waves during fracturing of the material. The energy passes through the material as ultrasound and sound waves and is detected on the surface of an object using a piezoelectric transducer (a microphone). Owing to digital capture and processing of single AE events in real time, the method is capable not only of continual monitoring of crack propagation but also of predicting macro damage which is preceded by a noticeable increase in the AE activity.
Speckle interferometry is used to determine the displacement field on an investigated surface through analysis of fringes formed by the interference of two light beams on a rough surface. Owing to the coherent dispersion of light on a rough surface, a characteristic granular pattern (speckles) is formed, therefore, the interferometric fringes of interest cannot be discerned visually and the images recorded require digital processing to gain the information. Hence, Digital Speckle Pattern Interferometry (DSPI) is the full name of the technique. The method is applied to measuring the displacement field with high precision. Therefore, measurements of moisture related dimensional change or thermal expansion in materials with non-homogenous displacement fields, as composite materials or wood, are a natural application of the technique in the area of heritage science.
Digital image correlation is a technique used to determine a displacement field caused in a material by a change in temperature or relative humidity, or by a mechanical impact. The method consists in comparing two images recorded prior to and after subjecting the investigated object to the impact. With the use of numerical algorithms, a mathematical transformation can be derived which transforms one image into the other and allows the displacement field to be computed. The method is far less complicated and faster to use than DSPI but less precise. For a correct use of the method, the surface investigated cannot be uniformly coloured and has to contain varying patterns.
Vacuum microbalance from CI Precision for determination of isotherms of water sorption. Standard amount of the analysed material – 0.1 g, the maximum amount 5 g, resolution 1 μg, maximum range of mass change +/- 500 mg. Equipped with a vacuum system for outgassing the sample, an automatic system of dosing water vapour and steering the measurement of adsorption and desorption isotherms. Temperature control with a thermostat in the range of 5 – 50 oC. It is possible to measure in parallel material’s moisture related dimensional change (swelling and shrinkage) in a chamber connected to the system of outgassing and dosing water vapour.
COMSOL MultiphysicsTM software with packages of heat transport and structural mechanics for modelling of diffusional transport of water vapour and stress/strain fields in historical objects.
Database of isotherms of water vapour sorption and moisture=related swelling/shrinkage for historical materials – 25 wood species contained in heritage objects, diverse kinds of paper, board, parchment, gesso, Japanese lacquer, paint layers.
Database of mechanical properties for materials relevant for cultural heritage field – diverse wood species, paper, parchment, gesso, Japanese lacquer, paint layers.