We study the crease instability of an incompressible Gent-Gent elastomer under general loading conditions. The Gent-Gent model has two distinct characteristics: the logarithmic nonlinearity triggered by energy term and the strain hardening due to limiting chain extensibility. By performing finite element analysis combined with an evaluation of surface tension, we investigate the effects of the two characteristics on the critical creasing onset and the creasing onset delayed by surface tension. The results show that uniaxial compression induces logarithmic nonlinearity that accelerates the critical creasing onset, whereas equibiaxial compression hastens the initiation of strain hardening that delays the critical creasing onset. In addition, logarithmic nonlinearity mitigates the delay in creasing onset caused by surface tension under the uniaxial condition, and strain hardening suppresses creasing in cooperation with surface tension under the equibiaxial condition. Conversely, under the plane strain condition, two characteristics have little effect on the creasing onset delayed by surface tension.

中文翻译：

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Gent-Gent 超弹性材料中的折痕不稳定性


我们研究了不可压缩的 Gent-Gent 弹性体在一般负载条件下的折痕不稳定性。 Gent-Gent 模型有两个明显的特征：由能量项引发的对数非线性和由于限制链延伸性而导致的应变硬化。通过进行有限元分析并结合表面张力评估，我们研究了这两个特性对临界折痕起始和表面张力延迟的折痕起始的影响。结果表明，单轴压缩会引起对数非线性，从而加速临界折痕的开始，而等双轴压缩会加速应变硬化的开始，从而延迟临界折痕的开始。此外，对数非线性减轻了单轴条件下由表面张力引起的折痕开始延迟，而应变硬化在等双轴条件下与表面张力配合抑制了折痕。相反，在平面应变条件下，这两个特性对表面张力延迟的压痕起始影响不大。