超高分子量ポリエチレン(UHMWPE)の動的構成モデル。温度とひずみ速度の効果を考慮した

Dynamic Constitutive Model of Ultra-High Molecular Weight Polyethylene (UHMWPE): Considering the Temperature and Strain Rate Effects.

• Kebin Zhang
• Wenbin Li
• Yu Zheng
• Wenjin Yao
• Changfang Zhao

抄録

UHMWPEの弾道性能には温度とひずみ速度が大きく影響するが，熱機械結合下でのUHMWPEの変形についてはほとんど研究されていない．UHMWPEの機械的性質に及ぼす温度とひずみ率の影響を調べるために、スプリットホプキンソン圧力バー(SHPB)装置を用いてUHMWPEの一軸圧縮実験を行った。実験結果から、UHMWPEは粘弾性-塑性材料に属し、硬化効果はUHMWPEが塑性域に入ると発生することがわかった。異なる温度とひずみ速度での応力-ひずみ曲線を比較した結果、UHMWPEはひずみ速度強化と温度軟化効果を示すことがわかった。Sherwood-Frostモデルを修正することによって、構成モデルは異なった温度のUHMWPEの動的機械特性を記述するために確立された。構成モデルを用いて計算した結果は実験データとよく一致した。本研究は、UHMWPEの耐弾道性材料としての設計の参考となるものである。

The temperature and strain rate significantly affect the ballistic performance of UHMWPE, but the deformation of UHMWPE under thermo-mechanical coupling has been rarely studied. To investigate the influences of the temperature and the strain rate on the mechanical properties of UHMWPE, a Split Hopkinson Pressure Bar (SHPB) apparatus was used to conduct uniaxial compression experiments on UHMWPE. The stress-strain curves of UHMWPE were obtained at temperatures of 20-100 °C and strain rates of 1300-4300 s. Based on the experimental results, the UHMWPE belongs to viscoelastic-plastic material, and a hardening effect occurs once UHMWPE enters the plastic zone. By comparing the stress-strain curves at different temperatures and strain rates, it was found that UHMWPE exhibits strain rate strengthening and temperature softening effects. By modifying the Sherwood-Frost model, a constitutive model was established to describe the dynamic mechanical properties of UHMWPE at different temperatures. The results calculated using the constitutive model were in good agreement with the experimental data. This study provides a reference for the design of UHMWPE as a ballistic-resistant material.