软材料因具有质量轻、响应速度快、变形大等优点，在现代科技领域中扮演着至关重要的角色。其中，水凝胶作为含有大量水分的高分子软材料，凭借其独特的三维网络结构和生物相容性在生物医学等领域展现出广泛的应用潜力。而在这些应用中，水凝胶通常会涉及到变形和失效，从而影响到材料稳定性和可靠性。因此，探究水凝胶在不同参数条件下的力学行为及影响规律，对水凝胶材料的设计和优化具有重要的指导意义。本文的主要研究内容如下：

首先，采用自由基聚合法制备了聚丙烯酸/壳聚糖双网络水凝胶，对水凝胶的溶胀率、含水量和压缩性能进行了测试，结果显示水凝胶的溶胀率和含水量分别可达1774%和94.6%，溶胀平衡状态下水凝胶的弹性模量最高可达112.1 kPa。

其次，对水凝胶的压缩性能进行了研究。基于Flory-Rehner自由能函数，推导并建立了水凝胶的超弹性本构模型，并编写用户自定义子程序UHYPER实现超弹性模型在ABAQUS软件中的定义。然后，建立了水凝胶的压缩有限元模型，模拟了其压缩行为，并验证了模型的合理性。基于该模型分析了含水量对水凝胶压缩性能的影响。当壳聚糖含量为5%，含水量为60%时，水凝胶满足伤口敷料应用的机械性能和含水量要求。

再次，分析了水凝胶在拉伸状态下的断裂性能。通过建立水凝胶的损伤模型，编写用户自定义子程序VUSDFLD实现其在ABAQUS软件中的定义，通过将拉伸实验数据与超弹性模型进行参数拟合，选取具有较优拟合效果的材料模型。建立水凝胶拉伸有限元模型，模拟其断裂行为，对模型进行网格无关性分析并验证其合理性。基于该模型分析了尺寸参数和预设缺口长度对水凝胶力学性能的影响。

最后，对水凝胶进行体外释药实验和粘附性能测试。结果表明，水凝胶在7天内的累积释药量接近93%，Higuchi和Korsmeyer-Peppas动力学模型与实验数据的拟合程度较高。通过180°剥离测试得到水凝胶与猪皮之间的粘附能为333.43 J/m²，对不同基材和人体皮肤也表现出较好的粘附性。这使得水凝胶在作为伤口敷料应用过程中不易脱落，为水凝胶的后续应用提供了一定的研究基础。

Soft materials have become indispensable in modern scientific and technological arenas, owing to their remarkable attributes such as low mass, rapid response speed, and high deformability. Hydrogels, a type of polymeric soft material rich in water content, have demonstrated extensive application potential in fields like biomedicine, primarily due to their distinctive three-dimensional network structure and excellent biocompatibility. However, in practical applications, hydrogels often experience deformation and failure, thereby undermining the stability and reliability of the materials. Therefore, investigating the mechanical behavior of hydrogels under diverse parameter conditions and understanding the influencing mechanisms is of vital importance for the design and optimization of hydrogel materials. The primary research contents of this paper are detailed as follows:

Firstly, polyacrylic acid/chitosan double-network hydrogels were synthesized via radical polymerization. Subsequently, comprehensive tests were conducted on the swelling ratio, water content, and compressive properties of the hydrogels. The experimental results revealed that the swelling ratio and water content of the hydrogels could reach as high as 1774% and 94.6%, respectively. Notably, in the state of swelling equilibrium, the elastic modulus of the hydrogels could attain a maximum value of 112.1 kPa.

Secondly, the compression properties of hydrogel were studied. Grounded on the Flory-Rehner free energy function, a hyperelastic constitutive model for the hydrogels was deduced and established. To implement this model within the ABAQUS software, a user-defined subroutine named UHYPER was meticulously developed. Subsequently, a compressive finite element model of the hydrogels was constructed to simulate their compressive behavior, and the validity of the model was rigorously verified. Leveraging this model, the impact of water content on the compressive properties of the hydrogels was systematically analyzed. It was found that when the chitosan content was set at 5% and the water content was 60%, the hydrogels satisfied the mechanical property and water content requirements essential for wound dressing applications.

Thirdly, the fracture properties of hydrogel in tensile state were analyzed. A damage model for the hydrogels was devised. A user-defined subroutine, VUSDFLD, was programmed to enable its definition within the ABAQUS software. By fitting the tensile test data with the hyperelastic model, a material model with superior fitting performance was selected. A tensile finite element model of the hydrogels was then established to simulate their fracture behavior. A mesh independence analysis was performed on the model to ensure its accuracy, and its rationality was verified. Based on this model, the effects of structural size and preset notch length on the mechanical properties of the hydrogels were investigated.

Finally, in vitro drug release experiments and adhesion performance tests were carried out on the hydrogels. The results indicated that the cumulative drug release of the hydrogels within 7 days approached 93%. The Higuchi and Korsmeyer-Peppas kinetic models exhibited a high degree of consistency with the experimental data. The adhesion energy between the hydrogels and pigskin, as determined by the 180° peeling test, was measured to be 333.43 J/m². Moreover, the hydrogels demonstrated good adhesion to various substrates and human skin. This characteristic ensures that the hydrogels remain firmly in place when applied as wound dressings, thereby providing a certain research basis for the subsequent application of hydrogel.

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