A Study on the Ultimate Strength of Thin Cylindrical Tubes under Static or Quasi-static Loading.

静态或准静态加载下薄圆柱管的极限强度研究。

• 批准号: 60550320
• 负责人: USAMI Tsutomu
• 金额: $ 1.28万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550320/
• 关键词: Pipe; Compression member; Ultimate strength; Initial imperfection; Numerical Analysis; 実験

This project is to determine theoretically and experimentally the load carrying capacity of short fabricated cylindrical tubes under compressive loading. The tests were carried out on 10 fabricated pipes in which 8 were for compression tests and 2 were for residual stress measurements. In addition, initial out-of-straightness(OOS) and out-of-roundness(OOR) were measured for all the specimens. From the experiment, the following were observed: (1)Initial OOS and OOR are well below the specified tolerances of ECCS and API. (2) Measured residual stresses are similar in shape to those in a reference and the maximum compressive residual stress was about 20% of the yield stress. (3)Observed average stress-strain curves of test specimens with the same radius/thickness ratio are similar in shape up to the maximum load, but become different after the peak load, i.e., steeper descending part was observed for longer specimen. (4)Observed ultimate strength may be well predicted by the basic strength formular of cylindrical tubes specified in the current Japanese highway bridge specification. Theoretical study was also conducted by applying the Dynamic Relaxation Method (DR method). A computer program has been developed to make an elastic-plastic large displacement analysis of cylindrical shells. The following are obtained from the study: (1)It is possible to reduce the number of iterations by determining iteration parameters from the maximum and minimum eigenvalues of the stiffness matrix. (2)The computed ultimate strengths of cylindrical shells with initial imperfections fall generally between the strengths predicted by the basic strength formulas of the Japanese highway bridge specifications and ECCS.

本计画系以理论与实验方法，探讨短圆管在受压状态下之承载能力。对10根预制管进行了试验，其中8根进行了压缩试验，2根进行了残余应力测量。此外，测量所有试样的初始不直度（OOS）和不圆度（OOR）。从实验中观察到以下情况：（1）初始OOS和OOR远低于ECCS和API规定的公差。(2)测得的残余应力在形状上与参考中的残余应力相似，并且最大压缩残余应力约为屈服应力的20%。（3）相同半径/厚度比的试件的平均应力-应变曲线在最大载荷之前形状相似，但在峰值载荷之后变得不同，即，长标本下降段较陡。（4）用日本现行公路桥梁规范中的圆管基本强度公式可以很好地预测实测极限强度。本文还应用动态松弛法（DR法）进行了理论研究。本文编制了圆柱壳弹塑性大位移分析的计算机程序。研究结果表明：（1）根据刚度矩阵的最大和最小特征值确定迭代参数，可以减少迭代次数。（2）计算出的具有初始缺陷的圆柱壳的极限强度一般落在日本公路桥梁规范和ECCS的基本强度公式预测的强度之间。

项目成果

Tsutomu Usami, Tetsuhiko Aoki, Masahiro Katoh: "Initial imperfection Measurement and Compressive Tests of Steel Pipes." Proceedings of JSCE.

Tsutomu Usami、Tetsuhiko Aoki、Masahiro Katoh：“钢管的初始缺陷测量和压缩试验。”

宇佐美勉,青木徹彦,加藤正宏: 土木学会論文集.

Tsutomu Usami、Tetsuhiko Aoki、Masahiro Kato：日本土木工程师学会会议录。