METHOD FOR DETERMINING MECHANICAL PROPERTIES OF THIN FILM MEMBRANES FORMED OVER ROUND HOLES Russian patent published in 2021 - IPC G01N3/12 

FIELD: strength properties study.

SUBSTANCE: invention relates to the study of the strength properties of films and membranes, the analysis of the work of products based on them. The invention can be used to analyze the dependence of the deflection on excess pressure when testing films and membranes and subsequent calculations of the parameters of pressure sensors made on their basis. Preparation of samples during testing includes fixing a crystal with a membrane on a holder, fixing the initial position and shape of the membrane when the sample is freely placed on the table surface, calculating the surface area of the membrane S - for a simple membrane shape by analytical calculation, and for a complex membrane shape numerically using overlaying a triangular mesh, the initial effective membrane deflection w₀=w_e is calculated based on the analysis of the total membrane surface area S and the area of its base S₀=πа², where а is the radius of the hole in the substrate, over which the membrane is formed, from the relation after that, the holder with the sample is fixed in the experimental setup to create an overpressure so that the shape of the membrane and its effective deflection do not differ from the shape and effective deflection of the membrane on the crystal freely located on the surface of the table. When one-sided excess pressure is applied to the sample, the current topography of the membrane surface is fixed and the value of the current vertical displacement of the top of the formed membrane dome relative to the initial position is determined - the change in the membrane deflection w relative to w₀. An analysis of the change in the topography of the membrane surface with an increase in one-sided excess pressure is carried out, including the moment of change in the position of the membrane relative to the surface of the substrate for flapping membranes. To calculate the mechanical properties and analyze the relationship between the applied overpressure P and the corresponding maximum membrane deflection w, observed in the center of the membrane, the values determined in the nonlinear section of the dependence w(P) - near high pressures are used, while the difference between the current membrane deflection in the presence of excess pressure P and the initial effective deflection w₀ in the absence of applied excess pressure is used as the deflection w.

EFFECT: increasing the accuracy of the study of film materials and products based on them, in particular, single-layer and multilayer membranes with a thickness of the order of a few micrometers or less, including those with an initial deflection in the absence of excessive pressure, including membranes with a complex initial shape of the surface topography, including flapping membranes; increasing the clarity, convenience and sensitivity of the analysis of the dependence of membrane deflection on excess pressure.

1 cl, 2 dwg