Browsing by Author "WENG, CC"

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A STUDY ON ACOUSTIC-EMISSION CHARACTERISTICS OF FLY-ASH CEMENT MORTAR UNDER COMPRESSION
(1994)
TAM, MT
;
WENG, CC
;
交大名義發表
;
土木工程學系
;
National Chiao Tung University
Acoustic Emission (AE) monitoring of the integrity of material has been widely regarded as a potentially new nondestructive testing method. This study is devoted to the investigation of AE characteristics of fly ash cement mortar (FACM) under uniaxial compression. The test results of 72 specimens were reported. The major experimental parameters include the AE signals, the amount of cement replaced by fly ash, compressive strength, strain and age of the FACM. The test results showed that the characteristics of the detected AE signals during the compression process contain potentially useful information for judging the stability of the specimens under compression. Good correlation between the AE signals and the major parameters of FACM was observed. Also, a study on the AE Kaiser effect showed that Kaiser effect existed in FACM up to 80% of its ultimate strength.
ACOUSTIC-EMISSION CHARACTERISTICS OF MORTAR UNDER COMPRESSION
(1992-07-01)
WENG, CC
;
TAM, MT
;
LIN, GC
;
交大名義發表
;
土木工程學系
This research is devoted to the study of the characteristics of acoustic emission (AE) signals of mortar under uniaxial compression. A total of 40 specimens were tested, in which the water-cement ratio, age, compressive strength and strain were the major parameters of mortar related to the AE signals. In addition, different compressive modes were used in the tests in order to investigate the AE Kaiser effect in mortar. From the test results, good correlation between the AE signals and the major parameters of mortar was observed. The experimental findings may provide useful information for further understanding of the AE characteristics of concrete and reinforced concrete.
ACOUSTIC-EMISSION CHARACTERIZATION OF A MEDIUM STRENGTH STEEL DURING HYDROGEN PERMEATION PROCESSES
(1992-06-01)
WENG, CC
;
LIN, GC
;
CHEN, RT
;
交大名義發表
;
土木工程學系
The characteristics of acoustic emission (AE) signals detected from the hydrogen permeation test of a medium strength steel were investigated. The aims of this research are to study the correlation between the AE signals and the severity of hydrogen-induced damages, and to investigate the relationship between the AE signals and the variation in hydrogen permeation current. In this study, an electrochemical approach using Devanathan's dual-cell method was adopted for the hydrogen permeation test. A total of five specimens were tested with a charging current varying from 10 to 60 mA. From the test results, good correlation was observed between the detected AE signals and the severity of the hydrogen-induced blistering and cracking. Also, it was found that the variation in the hydrogen permeation current showed a close correlation with the detected AE energy and events.
ACOUSTIC-EMISSION KAISER EFFECT IN FLY-ASH CEMENT MORTAR UNDER COMPRESSION
(1995-11-01)
TAM, MT
;
WENG, CC
;
交大名義發表
;
土木工程學系
;
National Chiao Tung University
Acoustic-emission (AE) technology is considered a potential new testing method to monitor the integrity of concrete materials, This study is devoted to the investigation of the AE Kaiser effect in fly-ash cement mortar (FACM) under uniaxial compression. The major experimental parameters include the amount of cement replaced by fly ash, curing time, compressive strain and stress, loading pattern, and loading rate. The test results showed that the AE Kaiser effect existed in FACM specimens up to 80% of its ultimate strength. Good correlation between the variation of the AE signals and the compressive strains was observed. In addition, the results indicated that the AE Kaiser effect existed in FACM specimen during different curing periods of three, seven, 14, and 28 days. These observations suggested that the AE Kaiser effect has good potential to be used as a new tool to monitor the loading history of concrete materials.
COLD-BENDING OF THICK HIGH-STRENGTH STEEL PLATES
(1990-01-01)
WENG, CC
;
WHITE, RN
;
交大名義發表
;
National Chiao Tung University
COMPRESSION TESTS OF COLD-FORMED STEEL COLUMNS
(1990-05-01)
WENG, CC
;
PEKOZ, T
;
土木工程學系
;
Department of Civil Engineering
EFFECT OF RESIDUAL-STRESS ON COLD-FORMED STEEL COLUMN STRENGTH
(1991-06-01)
WENG, CC
;
交大名義發表
;
土木工程學系
;
National Chiao Tung University
;
Department of Civil Engineering
The effect of residual stress on the flexural buckling strength of cold-formed steel columns is studied. Based on the results of 93 column tests and the measured residual stresses, significant relation is observed between the reduction of column strength, the magnitude and distribution of residual stress, and the flat-width ratio of the plate element of the cold-formed section. In this study, a new concept called the "second reduction" is developed to account for the effect of the residual stresses on the local buckling behavior of cold-formed steel columns. Based on this concept, a possible design procedure is outlined for the prediction of the flexural buckling strength of cold-formed steel columns. The theoretical predictions are found to be in good agreement with the test results.
MEASUREMENT OF RESIDUAL-STRESSES IN WELDED STEEL JOINTS USING HOLE DRILLING METHOD
(1992-03-01)
WENG, CC
;
LO, SC
;
交大名義發表
;
土木工程學系
;
National Chiao Tung University
An experimental investigation of the residual stresses in three types of welded structural steel joint is presented. A total of twelve specimens was tested. In this investigation, the blind hole-drilling method of ASTM E837 was used - adapted and improved for determination of residual stresses. To account for the effect of local plasticity due to stress concentration near the drilled hole, new calibration coefficients were obtained by carrying out a series of calibration tests. Then, the residual stresses in the welded joints were determined using the new coefficients. The improved hole drilling method presented in this paper was found to be much less time consuming than the conventional sectioning (saw cutting) method for residual stress measurement. The final results obtained in this study showed good agreement with the residual stresses obtained by previous researchers using the sectioning method.
RESIDUAL-STRESSES IN COLD-BENT THICK STEEL PLATES
(1990-01-01)
WENG, CC
;
WHITE, RN
;
交大名義發表
;
National Chiao Tung University
RESIDUAL-STRESSES IN COLD-FORMED STEEL MEMBERS
(1990-06-01)
WENG, CC
;
PEKOZ, T
;
土木工程學系
;
Department of Civil Engineering
STUDY ON MAXIMUM STRENGTH OF COLD-FORMED STEEL COLUMNS
(1992-01-01)
WENG, CC
;
LIN, CP
;
交大名義發表
;
土木工程學系
;
National Chiao Tung University
Based on the approximate Jezek's method of beam-column theory, a computerized analysis was performed to determine the maximum strength of cold-formed steel columns. In this study, the effect of residual stress and initial imperfection on the column strength were taken directly into account in the analysis. In addition, the influence of residual stress on the local buckling strength of the cold-formed sections also was accounted for by using a new concept, called second reduction. The predicted column strengths were compared with the results of 104 column tests by previous researchers. From the results of the analysis, this study obtained a new column-strength curve for predicting the maximum strength of cold-formed steel columns. The predicted values showed good agreement with the test results.