Viscoelastic behavior of UHMWPE: experimental DMA and parametric modeling

This work examines the dynamic mechanical behavior of ultra-high molecular weight polyethylene (UHMWPE) with emphasis on the influence of temperature, humidity, and aging, factors that govern its reliability in armor applications. Although UHMWPE is widely recognized for its high tensile and impact strength, reported values of its modulus vary significantly due to testing conditions. To address this, dynamic mechanical analysis (DMA) is conducted over a wide frequency and temperature range to quantify the storage modulus, loss modulus, and damping factor (Tan δ). The results indicate a systematic decrease in storage modulus and an increase in damping under combined exposure to temperature and humidity (individual effects are not considered). The Williams–Landel–Ferry (WLF) approach enables prediction of long-term behavior beyond the experimental frequency window using time–temperature superposition (TTS) to construct master curves. The extended frequency response represents model-based extrapolation obtained through TTS rather than direct long-term experimental aging. Prony series parameters are subsequently extracted from the complex modulus curves using curve approximation and implemented in finite element simulations. To validate these parameters, a lumped material model (generalized Maxwell) is developed, which shows good agreement with experimental trends. The combined experimental and modeling framework provides a pathway to predict UHMWPE performance under environmental conditions and supports the design of polymer-based protective systems.