On the stress, strength, and deformability of corroded steel plates

腐蚀钢板的应力、强度和变形能力

• 批准号: 14350519
• 负责人: SUMI Yoichi
• 金额: $ 9.34万
• 依托单位: National University Corporation Yokohama National University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350519/
• 关键词: corroded plate; surface geometry; elongation; ultimate strength; similarity law; size effect; stress analysis; structural integrity; 強度試験; 変形能試験; 表面形状計測; 任意表面形状加工; CAD・CAM; 寸法効果; 腐食形状再現加工; ランダムプロセス; 不規則表面形状; パワースペクトル; 形状数値生成; 表面形状加工; 摂

Although the fracture energy absorbed by a corroded plate may be considerably reduced due to its localization of plastic deformation during the fracture process, experimental and numerical investigations have not clarified the behavior in details yet. In the present study, experimental investigations are made by reproducing steel plates having surfaces similar to those due to actual corrosion, where the surface geometries are generated by a CAD system and steel plates are machined by a CAM system to simulate corroded surfaces. This approach is possible because the reductions of ultimate strength and elongation are mainly caused by the effects of the undulated surface geometry, and not because of the chemical process of corrosion. Having completed the CAD/CAM system, simulated fracture tests of corroded plates can be carried out very efficiently without the corrosion process to prepare the test specimens.Three kinds of series tests have been carried out with regard to the ultimate strength and the deformability of corroded plates ;1.tests of similarity for pitting corrosion,2.tests to examine the effects of pitting patterns,3.tests to examine the sample-size effects of test plates with general corrosion.The main conclusions are as follows ;1.Considerable reduction of deformability is observed for plates with pitting and general corrosion.2.Different size coupons with the same geometries give almost the same results so that similarity law exists for a certain range of the size of test specimens.3.Isolatedpits show considerable reduction of elongation in comparison with those due to densely existing pits.4.With regard to the size effect of test specimen, smaller coupons exhibit higher ultimate strength and elongation. This clear tendency may suggest the needs of further research to find out the proper test procedure in order to estimate the mechanical properties of corroded plates of an actual ship.

尽管由于断裂过程中塑性变形的定位，腐蚀板吸收的断裂能可能会大大减少，但实验和数值研究尚未详细阐明这种行为。在本研究中，通过复制具有与实际腐蚀相似的表面的钢板进行实验研究，在这种腐蚀中，表面几何形状是由CAD系统产生的，而钢板是由CAM系统加工的，以模拟腐蚀表面。这种方法之所以可能，是因为最终强度和伸长的减少主要是由波动表面几何形状的影响引起的，而不是由于腐蚀的化学过程。完成了CAD/CAM系统后，可以非常有效地进行腐蚀板的模拟断裂测试，而无需腐蚀过程以准备测试样品。三种串联测试是针对最终强度和腐蚀层的相似性效果的最终强度和腐蚀效果的速度效应的2.tests效应的效果的效果的最终强度和变形性的效应的三种串联测试。主要结论如下； 1.具有斑点和一般腐蚀的板的可比可变形性降低。2。具有相同几何形状的不同尺寸优惠券给出了几乎相同的结果，因此相似性法律的相似性法律与测试样品的一定尺寸相比，相似的范围与这些范围相比，这些均具有相当的范围。3.ISOLITY的差异。对于测试标本的尺寸效应，较小的优惠券表现出更高的最终强度和伸长率。这种清晰的趋势可能表明需要进一步研究以找出适当的测试程序，以估算实际船舶腐蚀板的机械性能。

项目成果

Stress analysis of an undulated plate by the combined first order perturbation and alternating method.

采用一阶扰动和交变相结合的方法对波状板进行应力分析。

• 发表时间: 2001
• 期刊: 日本造船学会論文集 189
• 作者: Y.Sumi;A Rahbar-Ranji
• 通讯作者: A Rahbar-Ranji

基礎材料力学

基础材料力学

• 发表时间: 2004
• 作者: 高橋幸伯;町田進;角洋一
• 通讯作者: 角洋一

船体構造保全情報システムのための要素技術に関する研究-EXPRESS-Xを用いた強度解析モデル生成手法-

船舶结构维修信息系统要素技术研究-基于EXPRESS-X的强度分析模型生成方法-

• 发表时间: 2003
• 期刊: 日本造船学会論文集 194
• 作者: 川村恭己;藤田英理;菊地泰史;角洋一
• 通讯作者: 角洋一

Lifecycle Management of Structural Integrity of Ships

船舶结构完整性的生命周期管理

• 发表时间: 2004
• 期刊: Transaction of the Society of Naval Architects of Japan 882
• 作者: Y.Sumi

Y.Sumi, A.Rahbar-Ranji: "Stress analysis of an undulated plate by the combined first order perturbation and alternation method"日本造船学会論文集. 189. 225-230 (2001)

Y.Sumi、A.Rahbar-Ranji：“通过组合一阶扰动和交替法对波状板进行应力分析”日本造船学会汇刊 189. 225-230 (2001)。