EFFICIENCY OF MICROSTRUCTURE ANALYSIS IN EVALUATING THE STRENGTH CHARACTERISTICS OF POLYURETHANE FOAMS

Abstract

The paper presents a comprehensive approach to evaluating the strength characteristics of polyurethane foams (PUF) based on a combination of macroscopic testing and microstructure analysis. The study is founded on varying the weight ratios of the primary components—polyol and isocyanate—enabling the formation of test specimens with diverse topological parameters of the porous matrix. Numerical and graphical interpretation of the compression results was conducted using cyclic loading within the plastic deformation zone to identify the stages of cell failure. The influence of the formulation on the stability of the plateau stress and the nature of residual deformation accumulation in the cell walls and struts was investigated. A comparative analysis of the mechanical response for both traditional and modified PUF compositions was performed across variations in structural energy absorption. Through geometric modeling of a hexagonal network, the relationship between changes in cell face tilt angles and the macroscopic yield strength of the material was established. Effects of local stress concentration at microstructure nodes, which dictate the onset of stability loss in the porous framework, were identified. The study demonstrates the versatility of the developed approach for the predictive design of polymer compositions with predetermined performance properties for critical engineering structures.