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。

基本信息

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

项目摘要

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.

该项目是在理论上和实验上确定压缩负荷下短构成圆柱管的负载能力。对10个制造的管道进行了测试，其中8个用于压缩测试，2个用于残留应力测量。另外，针对所有标本测量了初始脱水（OOS）和跨环（OOR）。从实验中可以观察到以下内容：（1）初始OOS和OOR远低于ECC和API的指定公差。（2）测得的残余应力与参考中的应力相似，最大压缩残留应力约为屈服应力的20％。（3）观察到的具有相同半径/厚度比的测试样品的平均应力 - 应变曲线的形状相似至最大负载，但在峰值载荷后变为不同，即，对于更长的样品，观察到较陡的降低部分。（4）观察到的最终强度可以通过当前日本高速公路桥规范中指定的圆柱管的基本强度很好地预测。还通过应用动态弛豫方法（DR方法）进行了理论研究。已经开发了一项计算机程序来对圆柱形壳进行弹性塑料大位移分析。以下是从研究中获得的：（1）可以通过从刚度矩阵的最大和最小特征值确定迭代参数来减少迭代次数。（2）具有初始缺陷的圆柱形壳的计算最终强度通常落在日本高速公路桥规范和ECC的基本强度公式和ECC所预测的强度之间。