The influence of measurement temperature on the high velocity (>100 m/s) impact performance was investigated for three thermosetting epoxy resin S-2 glass composite systems. These three model resins were chemically similar but have different glass transition temperatures (T_g) and molecular weights between crosslinks (M_c) through the use of different diamine curing agents (Jeffamine® D230, D400, and D2000). Impact performance was quantified by the projectile kinetic energy absorbed (KE₅₀) as calculated from the characteristic ballistic velocity (V₅₀) of the composites during high velocity impact. Among the resin systems, the KE₅₀ remained essentially constant over a broad range of temperatures for each composite set and modestly increased with decreasing M_c. The superficial damage area associated with delamination showed remarkable sigmoidal behavior as a function of the testing temperature relative to the T_g (T-T_g). Damage was high for low T-T_g values (glassy resin) and decreased as the resin traversed its T_g into the rubbery region. These damage area trends were found to depend on the resin M_c, with higher M_c values resulting in lower overall damage area and a lower inflection point temperature. High speed videography of the back surface of the samples showed that lower damage areas correlated with an increased back face deflection, which enabled energy absorption with relatively less delamination. Composite mechanical tests were performed to validate the impact performance and explain the deformation mechanisms observed during impact energy dissipation. Our results illustrate the critical importance of the resin architecture and temperature-dependent viscoelastic behavior on the impact properties of composites for impact-resistance applications.

研究了三种热固性环氧树脂S-2玻璃复合体系的测量温度对高速（> 100 m / s）冲击性能的影响。这三种模型树脂在化学上相似，但是通过使用不同的二胺固化剂（Jeffamine®D230，D400和D2000），具有不同的玻璃化转变温度（T _g）和交联之间的分子量（M _c）。冲击性能通过吸收的弹丸动能（KE ₅₀）进行定量，该动能由复合材料在高速冲击过程中的特征弹道速度（V ₅₀）计算得出。在树脂体系中，KE ₅₀在每个复合组的宽温度范围内保持基本恒定，并且随着M _c的降低适度增加。相对于T _g（TT _g），与分层相关的表面损伤区域表现出显着的S形行为，这是测试温度的函数。对于低TT _g值（玻璃状树脂），损坏较高，并且随着树脂横越其T _g进入橡胶状区域而降低。发现这些损伤面积趋势取决于树脂M _c，其中M _c较高值会导致总损坏面积降低和拐点温度降低。样品背面的高速摄像显示，较低的损坏区域与背面偏斜增加相关，从而能够以相对较少的分层进行能量吸收。进行了复合机械测试以验证冲击性能并解释在冲击能量耗散期间观察到的变形机理。我们的结果说明了树脂结构和温度相关的粘弹性行为对耐冲击应用复合材料的冲击性能的至关重要性。