衝擊載荷下的液動潤滑行為廣泛存在於軸承、齒輪及聚合物元件中，然而傳統彈性液動潤滑理論難以描述黏彈性固體在瞬態載荷下的時間依賴響應。本研究針對剛球正向衝擊覆有潤滑膜之Maxwell模型黏彈性基材，建立Maxwell-模型衝擊黏彈性液動潤滑(Impact-VEHL)數值模型，將暫態Reynolds方程式、油膜厚度方程式、剛球運動方程式與Maxwell黏彈性本構關係進行耦合，以分析衝擊過程中的油膜壓力、膜厚、基材變形及剛球運動。研究另建立彈性與黏彈性衝擊乾接觸模型，並以衝擊彈性液動潤滑(Impact-EHL)作為比較基準，探討初始衝擊速度、阻尼器黏滯係數、彈性模數及特徵鬆弛時間對系統響應的影響。結果顯示，Maxwell-模型在極大黏滯係數情況下會近似純彈性，在極小黏滯係數情況下會趨於黏性，而提高剛球初始衝擊速度會增加油膜壓力、基材變形及能量損失，但會縮短接觸時長；降低阻尼器黏滯係數會使基材更容易累積黏性變形，造成中心油膜壓力與剛球回彈速度下降，並增加膜厚、殘留位移及接觸時長。提高彈性模數則會增加油膜壓力與峰值載荷，同時降低最大基材位移量及接觸時長；在阻尼器黏滯係數固定時，各個條件卸載後的殘留位移相近。當特徵鬆弛時間固定並同步改變彈性模數與阻尼器黏滯係數時，各組案例仍呈現不同的壓力、載荷、變形及膜厚結果，表示特徵鬆弛時間僅能描述材料反應的相對時間尺度，無法取代個別材料參數。恢復係數分析亦顯示，納入基材表面速度的相對恢復係數較能反映剛球與基材的實際分離狀態。整體而言，黏彈性基材的延遲變形與黏性耗能會重新分配油膜壓力、改變膜厚形貌並抑制剛球回彈，說明Impact-VEHL必須同時考慮流體承載、材料時間相依性及衝擊時間尺度。

This study establishes a fully coupled numerical model for impact viscoelastohydrodynamic lubrication (Impact-VEHL), in which a rigid ball normally impacts a lubricated substrate represented by the Maxwell model. The transient axisymmetric Reynolds equation, film-thickness relation, rigid-ball equation of motion, load balance, and Maxwell constitutive equation are solved simultaneously by the finite element method. Elastic and viscoelastic dry-impact cases are first examined to identify the solid response, and impact elastohydrodynamic lubrication (Impact-EHL) is used as the elastic reference for the lubricated cases. The results confirm that a very large dashpot viscosity makes the Maxwell response approach the elastic limit, whereas a very small value produces a viscosity-dominated response. For dry impact, increasing the magnitude of the initial impact velocity raises the peak pressure, maximum deformation, and absolute energy loss, but shortens the contact duration. For Impact-VEHL at a fixed elastic modulus, reducing the dashpot viscosity promotes time-dependent deformation, lowers the central film-pressure peak and rebound velocity, and increases residual deformation and the duration of load support. These findings demonstrate that lubricant squeeze action and substrate viscous dissipation jointly govern transient pressure, film geometry, and rebound.

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