## 3 Results
### Force-Time  
Examination of the force-time traces of the specimens revealed a more nuanced hierarchy of stiffness, damage tolerance and thermal recovery across the four laminate composite architectures. The untreated specimen (Figure 4a) exhibited a smooth rise to approximately 1950 N (\(\pm\) 150 N) followed by a ragged plateau and a secondary hump, features that are typical of brittle matrix cracking and a subsequent delamination. Upon re-impact (V1U), the peak force was reduced by \(\sim\)25% to approximately 1450 N (\(\pm\) 190 N) and advanced catastrophic unloading, confirming substantial stiffness loss. Thermal conditioning (V2T) did not restore the peak; instead, it delayed force build-up, confirming that heat only relaxed residual stresses without healing the damage network. Virgin fiber/epoxy laminates demonstrated significant mechanical deterioration under repeated impacts and thermal cycling. The observed drop in force for V1U and V2T suggested matrix embrittlement, likely due to interfacial degradation and thermal effect. All untreated and re-impacted lines (Figure 4b) clustered tightly, peaking at approximately 2100 N (\(\pm\) 140 N), indicating \(\sim\)5% better performance [46], with only a 5% loss between first and second impacts, highlighting the crack-arrest capability of the PAN mat. However, the treated specimen (N2T) reached only to approximately 1800 N (\(\pm\) 150 N), and its gradual rise suggested matrix-fiber debonding. Thus, nanofibers delivered excellent intrinsic damage tolerance but limited thermal repairability when acting alone. N2T's drop may have resulted from slight fiber shrinkage and matrix-nanofiber interface stress mismatch following heating. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Specimen** & **1 st Impact** & **2 nd Impact** & **1 st Impact** & **2 nd Impact** \\
**Type** & **(Untreated)** & **(Untreated)** & **(Treated)** & **(Treated)** \\ \hline Virgin & V1 & V1U & V2 & V2T \\ \hline Nanofiber & & & & \\ Interlayered & N1 & N1U & N2 & N2T \\ \hline PE-Modified & P1 & P1U & P2 & P2T \\ \hline Hybrid & H1 & H1U & H2 & H2T \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Specim groups according to treatment conditions and impact tests. The first impact on the PE-modified specimens (Figure 4c) exhibited a stepped ascent culminating at \(\sim\)2000 N (\(\pm\) 135 N) with distinct oscillations. These oscillations were attributed to local shear-yielding and intermittent fiber-matrix debonding around PE inclusions, which dissipated energy in discrete bursts while maintaining overall stiffness. Upon second impact (P1U), the peak force dropped to \(\sim\)1600 N (\(\pm\) 200 N), corresponding to a \(\sim\)25% reduction, and the ascent was interrupted by a deep force valley, indicating that pre-existing cracks had opened and temporarily impeded load transfer until adjacent regions engaged. The broader post-peak tail indicated a switch from brittle delamination to more ductile, friction-assisted sliding mechanism. Re-impact after heat treatment (P2T), in contrast to the virgin case, restored the load force to \(\sim\)2000 N (\(\pm\) 150 N), representing a 25% gain over its untreated counterpart. The force-time trace displayed a dual-peak profile: an early shoulder followed by the global maximum. PE alone demonstrated a thermo-reversible toughening effect, provided that a sufficient mobile phase was available to damaged interfaces, thereby contributing to energy dissipation via plastic deformation and suppressing crack propagation. Heat appeared to induce partial softening or fusion at the PE-epoxy interface, leading to improved impact load accommodation, consistent with thermoplastic bridging mechanisms. The hybrid untreated specimens (Figure 4d) retained their smooth, triangular curves, peaking at \(\sim\)2400N (\(\pm\) 130 N). Upon re-impact (H1U), a modest \(\sim\)4% reduction was observed.