Several biological materials are fibre networks infused with fluid, often referred to as fibrous gels. An important feature of these gels is that the fibres buckle under compression, causing a densification of the network that is accompanied by a reduction in volume and release of fluid. Displacement-controlled compression of fibrous gels has shown that the network can exist in a rarefied and a densified state over a range of stresses. Continuum chemo-elastic theories can be used to model the mechanical behaviour of these gels, but they suffer from the drawback that the stored energy function of the underlying network is based on neo-Hookean elasticity, which cannot account for the existence of multiple phases. Here we use a double-well stored energy function in a chemo-elastic model of gels to capture the existence of two phases of the network. We model cyclic compression/decompression experiments on fibrous gels and show that they exhibit propagating interfaces and hysteretic stress–strain curves that have been observed in experiments. We can capture features in the rate-dependent response of these fibrous gels without recourse to finite-element calculations. We also perform experiments to show that certain features in the stress–strain curves of fibrous gels predicted by our model can be found in the compression response of blood clots. Our methods may be extended to other tissues and synthetic gels that have a fibrous structure.

中文翻译：

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纤维凝胶建模为具有双井能量景观的充满流体的连续体

几种生物材料是注入流体的纤维网络，通常称为纤维凝胶。这些凝胶的一个重要特征是纤维在压缩下弯曲，导致网络致密化，同时体积减少和流体释放。纤维凝胶的位移控制压缩表明，网络可以在一定范围的应力下以稀薄和致密的状态存在。连续化学弹性理论可用于模拟这些凝胶的机械行为，但它们存在以下缺点，即底层网络的存储能量函数基于新胡克弹性，无法解释多相的存在。在这里，我们在凝胶的化学弹性模型中使用双阱存储能量函数来捕获网络两相的存在。我们对纤维凝胶的循环压缩/减压实验进行建模，并表明它们表现出在实验中观察到的传播界面和滞后应力-应变曲线。我们可以在不依赖有限元计算的情况下捕获这些纤维凝胶的速率相关响应中的特征。我们还进行了实验，以表明我们的模型预测的纤维凝胶应力-应变曲线中的某些特征可以在血凝块的压缩响应中找到。我们的方法可以扩展到具有纤维结构的其他组织和合成凝胶。我们可以在不依赖有限元计算的情况下捕获这些纤维凝胶的速率相关响应中的特征。我们还进行了实验，以表明我们的模型预测的纤维凝胶应力-应变曲线中的某些特征可以在血凝块的压缩响应中找到。我们的方法可以扩展到具有纤维结构的其他组织和合成凝胶。我们可以在不依赖有限元计算的情况下捕获这些纤维凝胶的速率相关响应中的特征。我们还进行了实验，以表明我们的模型预测的纤维凝胶应力-应变曲线中的某些特征可以在血凝块的压缩响应中找到。我们的方法可以扩展到具有纤维结构的其他组织和合成凝胶。