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原文传递 Traffic Signal Pole Research. Final rept. (Aug 97-Aug 02).

题名：	Traffic Signal Pole Research. Final rept. (Aug 97-Aug 02).
作者：	Hamilton-H.R.; Puckett-J.A.; Gray-B.; Wang-P.; Deschamp-B.
关键词：	Poles-Supports; Traffic-signals; *Testing-.;Field-tests; Fatigue-tests; Finite-element-method; Static-tests; Acoustic-emission-testing.
摘要：	Fatigue levels were performed on three signal pole connection specimens that were removed from service because of indications of fatigue cracking based on visual inspection. Acoustic emission (AE) testing was conducted on the fatigue specimens at selected times during fatigue testing. The following conclusions can be made: (1) Feasibility of AE monitoring was established and a reasonable correlation between AE severity and crack growth rate were established during fatigue testing; (2) 'First Hit' filtering algorithm was created using Visual Basic programming. This program was used to calculate the severity and historic index from the AE feature data; (3) Severity indications varied with direction of load (push vs. pull) and damage location. This observation may indicate the need to bi-directionally load the structure in both the in-plane and out-of-plane direction to activate the fatigue crack propagation, thereby initiating acoustic emissions. Finite element analyses (FEA) were conducted on typical connection details and compared to the results of static tests on a specimen with an open connection. Key results are: (1) Significant distortion of the circular cross section of the post occurs when the mast-arm is loaded out-of-plane. Stresses near the corner of the connection are significantly higher than those caused by the in-plane loading; (2) Stress concentration factors were established for the analyzed connections. Factors for in-lane loading are approximately 10, for out-of-plane loading are approximately 20. The present WYDOT stiffened design does little to decrease stresses due to in-plane loading. (3) American Welding Society (AWS) recommendations for fatigue using actual hot-spot stress or stress concentration factors may be conservative for out-of-plane bending.
报告类型：	科技报告