Study on cylindrical uniaxial tensile test method of unsaturated polyester resin coating

DOI:	10.11809/bqzbgcxb2025.03.004
Keywords:	plate specimens; cylindrical specimens; uniaxial tension; stress concentration; coating
Abstract:	To address the significant stress concentration effects and large result dispersions observed in the uniaxial tensile tests of plate shaped dumbbell specimens for solid propellant coating layers, a design for cylindrical tensile specimens with unsaturated polyester resin coating layers is proposed. Simulation of plate and cylindrical specimens with different transition radii reveals that the cylindrical samples are more prone to fracture than the plate shaped specimens at the same transition radius, particularly exhibiting the shortest fracture time at a transition radius of 45 mm. The stress distribution in the cylindrical specimens is more uniform with smaller concentrated areas. Experimental results show that the tensile strength dispersion of cylindrical specimens at -40 ℃, 20 ℃, and 50 ℃ is 0.63%, 0.41%, and 0.46%, respectively, while the elongation rate dispersion is 0.70%, 0.34%, and 0.51%. In contrast, the tensile strength dispersion for plate specimens is 2.03%, 1.31%, and 1.26%, with elongation rate dispersions of 1.15%, 1.05%, and 1.57%. The effective data dispersion of the cylindrical specimens is lower than that of the plate specimens, and the effective rate of experimental data reaches 92%. The research indicates that the cylindrical specimens effectively reduce the dispersion of experimental results caused by stress concentration; the optimal engineering gauge length for the specimens is 12 mm with a transition radius of 45 mm. The cylindrical uniaxial tensile test method contributes to obtaining more reliable test results.
Issue:	Vol. 46 No. 3 (2025)
Published:	2025-03-31
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