The concept and fundamental analytical hypotheses of a new theory for ductile failure is introduced. This criterion is called ductile version of NN- criterion (DNN). This criterion depends on HRR field and energy approach in new shape. Using this criterion it can be easily to predict the failure process, the failure load and cracking properties can be investigated. This can be applied for ductile and ductile-brittle materials. This work is concentrated on developing of a new criterion to deal with the cracks of ductile materials in elastic-plastic fracture mechanics EPFM. Some researchers devoted their attention to deal with the cracks in ductile materials using the energy approach depending on the strain energy density criterion proposed by Sih (1983) and the so called HRR field presented by Hutchinson (1968) and Rice and Rosengren (1968). In this paper we treat the problem with a new method depending on NN theory El-Sheikhy and Nishimura (1999) and the new concept of strain energy components; the dilatational and distortion strain energy density. Theocarais and others used the volumetric component as (T_(max)) criterion (1982, 1984, 1986). Other researchers used total strain energy density (S_(min)) criterion Sih (1983). In this research we use the two components of strain energy density; volumetric component (S_v) and distortion component (S_d).
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机译：介绍了一种新的延性失效理论的概念和基本分析假设。此准则称为NN-准则（DNN）的延性版本。该标准取决于HRR领域和新形式的能量方法。使用该标准可以很容易地预测失效过程，可以研究失效载荷和开裂性能。这可用于延性和延性脆性材料。这项工作集中在制定新标准来处理弹塑性断裂力学EPFM中的韧性材料裂纹。一些研究者专注于利用能量方法处理延性材料中的裂纹，这取决于Sih（1983）提出的应变能密度准则以及Hutchinson（1968）和Rice and Rosengren（1968）提出的所谓HRR场。在本文中，我们根据NN理论El-Sheikhy和Nishimura（1999）以及应变能分量的新概念，采用一种新方法来解决该问题。膨胀应变应变能密度。 Theocarais和其他人使用体积分量作为（T_（max））准则（1982、1984、1986）。其他研究人员使用总应变能密度（S_（min））准则Sih（1983）。在这项研究中，我们使用应变能密度的两个分量。体积分量（S_v）和失真分量（S_d）。
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