This article investigates the prediction of the crack growth angle of an existing internal crack under mixed mode loading at the crack tip for an unfilled ethylene propylene diene terpolymer rubber (EPDM). For the realization of mixed mode loading, the cracks of the uniaxial loaded specimens were oriented with different angles to the loading direction. The energy density factor was used as a potential criterion for determining the crack growth angle. The determination of the strain energy density factor was carried out simulatively in Abaqus. The second-order Ogden model was used to describe the rubber-like material behavior. The relative local minimum of the strain energy density factor provides the possible growth angle. The experimental investigations show that the initial cracks grow orthogonally to the loading direction for the different crack orientation angles. For the crack orientation angle parallel to the load direction, the crack growth was observed because the strong stretching of the specimen caused strong necking in the crack region. The crack growth for the remaining crack orientation angles were induced due to shear loading at the crack tip. The predictive angle of different crack orientation angles shows very good accordance to the measured crack growth angles.

中文翻译：

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使用应变能密度因子预测混合模式载荷下未填充弹性体内部裂纹的裂纹扩展角

本文研究了未填充三元乙丙橡胶 (EPDM) 裂纹尖端混合模式加载下现有内部裂纹裂纹扩展角的预测。为了实现混合模式加载，单轴加载试件的裂纹与加载方向成不同的角度。能量密度因子被用作确定裂纹扩展角的潜在标准。应变能密度因子的测定在Abaqus中模拟进行。二阶 Ogden 模型用于描述类橡胶材料的行为。应变能密度因子的相对局部最小值提供了可能的生长角。实验研究表明，对于不同的裂纹取向角，初始裂纹与加载方向正交。对于平行于载荷方向的裂纹取向角，观察到裂纹扩展是因为试样的强烈拉伸在裂纹区域引起了强烈的颈缩。其余裂纹取向角的裂纹扩展是由于裂纹尖端的剪切载荷引起的。不同裂纹取向角的预测角与实测裂纹扩展角非常吻合。其余裂纹取向角的裂纹扩展是由于裂纹尖端的剪切载荷引起的。不同裂纹取向角的预测角与实测裂纹扩展角非常吻合。其余裂纹取向角的裂纹扩展是由于裂纹尖端的剪切载荷引起的。不同裂纹取向角的预测角与实测裂纹扩展角非常吻合。