The Licensing and Intellectual Property Department of JINR announces that on 7 May 2018, the Joint Institute for Nuclear Research received a patent for the invention “Method of determining Poisson ratio of sealed thin-walled polymer tube material”. The authors of the work are Volkov Aleksandr Dmitrievich and Tsamalaidze Zviadi

JINR staff congratulates the authors on receiving the patent for their invention!

More details about the invention

invention relates to methods for measuring the Poisson ratio of a material of a finished sealed thin-walled polymer tube and can be used to create coordinate detectors based on cylindrical thinwalled drift tubes, which, as a rule, include several thousand registration channels.Proposed method solves the problem of determining the value of the Poisson ratio of a tube without destroying the mechanical properties of the material. To do this, the tube material is mechanically stretched in the longitudinal direction, fixing the ends of the tube and measuring the tension value. Then, excess gas pressure is applied to the tube and its value is measured, and the tube tension is again measured. Change in tube tension due to the excess gas pressure depends on the pressure inside the tube and the Poisson ratio, which is determined from relation
μ=0.5(1-|ΔT|/PπR²)/(1-0.76√(h/R)/∜(1-μ²)),

where μ – Poisson’s ratio of tube material;
|ΔT|=|T_m-T₀| – modulus of the magnitude of the change in tension due to internal pressure;
T_m – tube tension at a given pressure;
T₀ – tube tension at atmospheric pressure;
P – the excess gas pressure inside the tube;
π – number pi,
R – the radius of the tube;
h – the thickness of the tube material.

To exclude the influence of the instrumental error of measuring the tension, the tension Tm measured at different values of the excess pressure inside the tube P_m. Obtained data T_m(P_m) is approximated by a linear relationship, on which the magnitude of the change in tension under the influence of internal pressure is determined without the influence of instrumental error ΔT_c and when calculating the Poisson ratio |ΔT|=|ΔT_c|.

EFFECT: method is applied in the region of linear deformation of the tube at a gas pressure in the interval P = 0–2 atm and is non-destructive.