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Marine structures such as ships and offshore platforms are mostly designed with damage tolerance and this design philosophy requires accurate prediction of fatigue crack propagation process. Now more and more people have realized that only a fatigue life prediction method based on fatigue crack propagation (FCP) theory has the potential to satisfy the accuracy requirement and to explain various fatigue phenomena observed. In the past several years, the authors’ group has made some efforts in developing a unified fatigue life prediction (UFLP) method for marine structures. The key issue for this development is to establish a “correct” crack growth rate relation. In this paper the improvement of the crack growth rate model is dealt with first. A new crack growth rate model based on the concept of partial crack closure is presented. The capability of the model is demonstrated. Secondly, studies on the engineering approaches to determine the parameters in the new crack growth rate model are carried out and validated by comparing with the experimental results on a wide range of alloys. Thirdly, the preliminary studies on some significant problems such as load sequence effect are presented. Finally, further studies for the application of the UFLP method to the fatigue strength assessment of marine structures are pointed out. 相似文献
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依据上海市宝山区重载交通状况,通过对重载交通道路存在的主要病害特征进行了成因分析与研究,发现裂缝和车辙是重载交通的主要病害。然后从材料、施工等角度提出了关于重载交通主要病害的防治策略,并针对典型路段给出了适用于重载交通道路的路面结构设计方案。最后从道路宏观管理角度提出了重载交通道路的管理建议。 相似文献
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水泥混凝土路面断板的原因与处治研究 总被引:3,自引:0,他引:3
本文对水泥混凝土路面断板进行了分类,并认真分析了各种路面断板的原因,针对断板病害,经过研究提出了一些预防措施和修复处治方案。 相似文献
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在寒冷地区,有时在贮存过程中会发生预制直埋保温管聚乙烯外护管开裂的现象,针对此现象,对外护管低温下的性能变化进行了简单的分析研究,说明了预制直埋式保温管在低温地区可以使用。 相似文献
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采用沥青加铺层结构是修补旧水泥路面的有效方法,但由于旧水泥路面裂缝的存在,沥青加铺层易产生反射裂缝。文章建立三维有限元模型,模拟在交通荷载作用下,通过分别改变加铺层模量、夹层模量、加铺层厚度、夹层厚度以及基础模量,得出加铺层应力响应的变化规律。其结论对实际工程中选取合理的修补方案具有一定的参考意义。 相似文献
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预应力混凝土连续箱梁底板锚下裂缝分析 总被引:4,自引:0,他引:4
由OVM锚具和楔形齿板组成的锚固体系在我国预应力混凝土连续箱梁中的应用已经非常广泛,但是如果设计和施工过程中考虑不周,巨大的锚下应力将会导致箱梁底板开裂。本文以广东某预应力混凝土连续箱梁齿板前底板开裂为工程背景,对其进行有限元分析计算,并根据计算结果和工程实际情况从理论上分析了开裂的原因。最后,本文还提出裂缝的处理意见和改善设计的具体建议。 相似文献
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