Systems operating in harsh environments face the dual challenge of external extreme shocks and internal degradation, a critical failure mode often overlooked in reliability engineering. This paper develops a novel \(\:{L}_{z}\)-transform model to analyze this coupled effect dynamically. Applied to a Doubly-Fed Induction Generator (DFIG), the model reveals a severe decline in performance: availability and reliability deteriorate asymptotically toward zero due to these combined stressors, with reliability falling more sharply due to the irreversibility of failures. To address this, a new maintenance strategy using dummy states is proposed. This approach dramatically improves system resilience, elevating both reliability and availability to near-perfect levels (~ 1.0). Comparative analysis shows the strategy completely mitigates time-dependent degradation, sustaining high performance indefinitely and improving vulnerable systems by orders of magnitude. Crucially, benefits are solely due to maintenance, not redundancy. This study proves proactive maintenance is indispensable for sustainable operation in shock-prone environments.
