The reference stress method (RSM) is a classical method to estimate [Formula: see text]-integral of creep crack. An extended reference stress method (ERSM) is given for the central cracked plate (CCP) under biaxial loading in this paper. The applicability and verification for the proposed ERSM is given. The study finds that the solutions with the proposed ERSM agree better than those of RSM under biaxial loading condition. A theoretical form to predict the relationship of [Formula: see text]-integral between biaxial loading and uniaxial loading is discussed. Relation between [Formula: see text]-integral and creep time under biaxial loading is validated and discussed.

中文翻译：

---

双轴荷载作用下中央开裂板的C∗-积分估计

参考应力法（RSM）是估计[公式：见正文]-蠕变裂纹积分的经典方法。本文给出了双轴载荷作用下中心裂纹板（CCP）的扩展参考应力法（ERSM）。给出了提议的 ERSM 的适用性和验证。研究发现，在双轴载荷条件下，提出的 ERSM 的解决方案比 RSM 的解决方案更好。讨论了一种理论形式来预测[公式：见正文]-双轴载荷和单轴载荷之间的积分关系。验证并讨论了[公式：见正文]-积分与双轴载荷下的蠕变时间之间的关系。