高分子凝膠係由固體網絡以及孔隙流體所組成，當孔隙流體流入固態網絡內時，凝膠將隨之潤漲(swelling)，當孔隙流體由固態網絡流出時，凝膠將隨之乾縮(shrinking)。高分子凝膠的力學性質在許多應用上顯得重要，包括破壞性質。凝膠依時性破壞之現象主要係與受外部載重所產生的初始孔隙壓力場及邊界滲透條件作用下所引起的流體流動有關。
在本文中，將分析具長度2a之中間裂縫之孔隙彈性體受遠端單軸應力或應變作用下，同時發生固體網絡變形與孔隙流體流動，探討當遠端邊界及近端裂縫面受不同滲透條件的四種混合形態之破壞問題。本文採用Ｊ積分原理，利用數值模擬於裂縫尖端處放置黏著元素(cohesive element)計算瞬時能量釋放率。數值結果與短時流動之理論預測值相吻合。當邊界之孔隙壓力值與受遠端載重所造成的初始孔隙壓力場值有所差異時，將產生近端或受遠端邊界影響之流動，進而影響曲線變化。當流動時間約為時，其中是材料幾何長度，是孔洞材料之壓密係數，材料已完成流動行為，其值達到完成流動狀態(drained state)之極限值。但完成流動狀態之值未必是曲線之最大值，特別是在應變控制條件下，當滲透邊界的孔隙壓力值與初始孔隙壓力值之差值為正值時。在應力控制條件下，最大值若發生在完成流動狀態前，其發生之原因不僅與受滲透邊界的孔隙壓力值與初始孔隙壓力值之差值有關外，亦與滲透條件之位置相關。
當凝膠之固體網絡具黏彈行為時，其破壞依時現象將同時受黏彈變形行為及流體流動行為所影響。本文分析具中間裂縫之孔隙黏彈體受雙軸遠端應力，且流體流動僅限於裂縫附近之破壞問題。當流體完成流動之時間與黏彈性網絡達到鬆弛時間有明顯差異時，其曲線將顯現出兩階段之行為。當材料達到鬆弛之時間在流體完成流動前，其值變化趨勢將由未完成鬆弛-未完成流動狀態(unrelaxed-undrained state)之極限值升至完成鬆弛-未完成流動狀態(relaxed-undrained state)之極限值，然值於孔隙流體完成流動行為後，即再升至完成鬆弛-完成流動狀態(relaxed-drained state)之極限值。當材料達到鬆弛之時間於孔隙流體完成流動之後時，值變化將從未完成鬆弛-未完成流動狀態(unrelaxed-undrained state)之極限值先升至未完成鬆弛-完成流動狀態(unrelaxed-drained state)之極限值，進而再升至完成鬆弛-完成流動狀態(relaxed-drained state)之極限值．本文成功預測上述四類狀態之極限值，並與所求之數值解相吻合。
若凝膠之固態網絡可承受極大變形，潤漲後其體積可為原體積之數倍大。由於側向束制的關係，所產生的側向壓力使其表面微小缺陷形成皺摺(wrinkling)現象。皺摺現象的發生與凝膠潤漲後的壓縮性，邊界之束制條件以及凝膠之厚度有關．本文藉由微擾分析以得到當凝膠在任意側向束制條件下之穩定性特徵方程式，並探討在特定束制條件下凝膠發生皺摺圖騰之可能性。在雙軸束制條件相同下，任意方向皆具相同皺摺波長；當雙軸束制條件不同時，不同方向則具有不同皺摺波長。皺褶圖騰為所有方向之可能組合。

Polymeric gels, which consist of a solid polymer network and liquid solvents, swell when the solvents are absorbed into the polymer network, and shrink when the solvents flow out of the polymer network. Mechanical properties of polymeric gels, including fracture properties, are important for many applications.
The time-dependent fracture phenomenon of polymeric gels is affected by fluid diffusion, which is strongly influenced by the initial pore pressure field attributed to loading and permeability conditions on the boundaries. In this study, the concurrent solid deformation and fluid migration for a center crack of finite length in a poroelastic medium subjected to uniaxial remote stress or strain is analyzed. Four mixed types of permeability conditions on the remote boundaries and the crack faces are considered. The instantaneous fracture energy is evaluated by a novel method, which uses J-integral around the cohesive zone embedded ahead of the crack tip in the simulations. The numerical results of are validated with the asymptotes predicted by stress intensities at small flow times. When there is a difference between the imposed pore pressure and the initial pore pressure caused by applying loading on the boundaries, the variation in is affected by short and long ranges of fluid flow, and reaches its drained limit at a time on the order of , where is the consolidation coefficient of porous materials. The drained limit may not be the maximum value of , especially when the difference on the remote boundaries is positive under strain control. For stress-control cases, whether the maximum occurs before drained state depends not only on the difference in pore pressure but also on where the permeable boundaries are.
When a solid network of a polymeric gel is found to exhibit viscoelastic behavior, the fracture phenomena can be affected by both flow-induced and viscoelastic deformations. This study analyzes the concurrent deformation of a mode-I center crack in a poroviscoelastic medium subjected to biaxial remote stresses for short-distance fluid flow. For the drainage time differing from the viscoelastic relaxation time, the curve exhibits a two-stage behavior. When viscoelastic relaxation is completed before fluid drainage, the value of at first changes from the unrelaxed-undrained limit to the relaxed-undrained limit and continues to increase till the relaxed-drained limit. When viscoelastic relaxation is postponed until after fluid drainage, the value of increases till the unrelaxed-drained limit and continues to increase till the relaxed-drained limit. This study predicts the four aforementioned limits and shows excellent agreements with numerical results.
Polymeric gels may incur large deformations and increase the volume by several times after swelling. Owing to the restrictions on lateral expansions and surface imperfections, the instabilities may appear in the form of wrinkling. Wrinkling is strongly governed by the compressibility of swollen gel, confinements and gel thickness. This study investigates surface wrinkling of a gel layer under arbitrary lateral confinements in the equilibrium state of swelling based on perturbation analysis. This work also discusses possible gel-solvent systems of wrinkling under different confinements. At equal biaxial confinements, the wrinkle pattern is a combination of plane waves with the same wavelength in all directions. Meanwhile, at non-equal biaxial confinements, the wrinkle pattern may be a sum of plane waves with dissimilar wavelengths and corresponding directions.

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