• Computers and Concrete
• /
• v.33 no.3
• /
• pp.265-273
• /
• 2024

Predicting fracture properties requires an understanding of structural failure behaviour in relation to specimen type, dimension, and notch length. Facture properties are evaluated using various testing methods, wedge splitting test being one of them. The wedge splitting test was numerically modelled three dimensionally using the finite element method on self compacting concrete specimens with varied specimen and notch depths in the current work. The load - Crack mouth opening displacement curves and the angle of rotation with respect to notch opening till failure are used to assess the fracture properties. Furthermore, based on the simulation results, failure curve was built to forecast the fracture behaviour of self-compacting concrete. The fracture failure curve revealed that the failure was quasi-brittle in character, conforming to non-linear elastic properties for all specimen depth and notch depth combinations.

• Smart Structures and Systems
• /
• v.30 no.3
• /
• pp.255-261
• /
• 2022

When no extensometer is available in a generic tensile-compression test carried out by a universal testing machine (for instance the model BIONIX from Material Testing Systems (MTS)), the test results only provide the relative displacement between the machine grips. The test does not provide any information on the local behaviour of the material. This contribution presents the potential of an application of Digital Image Correlation (DIC) toward the reconstruction of the behaviour along the specimen. In particular, the authors test a Ni-Ti shape memory alloys (SMA) specimen with emphasis on the coupling of the two measurement techniques.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.238-243
• /
• 2000

The effect of the temperature, the fatigue and the test speed on DEN(double edged notch) specimen which was made by the pp-rubber composites during fracture was stuied. DEN specimen was made on PP-rubber composites through the injection molding. With increasing temperature the fracture strength is linearly decrease and the fracture energy is first increase by $0^{\circ}C$ and after that decrease. In the same temperature the fracture strength during increasing the notch radius is hardly increase. The fracture behaviour at low and high test speed is different entirely. At high test speed plastic region is small and fracture behaviour was seen to brittle fracture tendency. The deformation mechanism of polypropylene-rubber composites during fracture was studied by SEM fractography. A strong plastic deformation of the matrix material ahead of the notch/crack occured. The deformation seem to be enhanced by a thermal blunting of the notch/crack.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.17 no.3
• /
• pp.97-105
• /
• 2013

In this paper, the a static experiment of on two reinforced concrete (RC) frame sub-assemblages was conducted to evaluate the seismic behaviors of existing RC frames that were not designed to support a seismic load. The specimens were a one span and actual-sized. One of them had two columns with the same stiffness, but the other had two columns with different stiffness values. As Regarding the test results, lots of many cracks occurred on the surfaces of the columns and beam-column joints for the two specimens, but the cover concrete splitting hardly occurred was minimal until the test ends. In the case of the specimen with the same stiffness offor the two columns, the flexural collapse of the left-side column occurred. However, in the case of the specimen with different stiffness values for of the two columns, the beam-column joint finally collapsed, even though the shear strength of the joint was designed to be strong enough to support the lateral collapse load. The nonlinear Nonlinear static analysis of the two specimens was also conducted using the uniaxial spring model, and the analytical results successfully simulated the nonlinear behaviour of the specimens in accordance with the test results.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05a
• /
• pp.499-502
• /
• 2005

Nowadays, the stripping work of form has generated some problems such as increasing total constructing cost result from delayed work schedule by the stripping work of form and environmental issues by wasting the debonded form. According to recent research for form work, it has studied about permanent form to solve economic and environmental problem which is commented above. In this study, high performance permanent form method was developed and tested by adopting COM and TEN specimens adopted on the Compression and Tensile section then the structural behaviour was investigated. In the test result, the specimen adopted the form showed better structural performance than control specimen in the point of ductility, failure mode and ultimate load.

• Steel and Composite Structures
• /
• v.15 no.6
• /
• pp.659-677
• /
• 2013

This paper introduces new specimens of Steel-Carbon Fibre Reinforced Polymer composite developed in accordance with standard test method and definition for mechanical testing of steel (ASTM-A370). The main purpose of this research is to study the behaviour of steel-CFRP composite specimen under uniaxial tension to use it in beams in lieu of traditional steel bar reinforcement. Eighteen specimens were prepared and divided into six groups, depending upon the number of the layers of CFRP. Uniaxial tensile tests were conducted to determine yield strength and ultimate strength of specimens. Test results showed that the stress-strain curve of the composite specimen was bilinear prior to the fracture of CFRP laminate. The tested composite specimens displayed a large difference in strength with remarkable ductility. The ultimate load for Steel-Carbon Fibre Reinforced Polymer composite specimens was found using the model proposed by Wu et al. (2010) and nonlinear FE analysis. The ultimate loads obtained from FE analysis are found to be in good agreement with experimental ones. However, ultimate loads obtained applying Wu model are significantly different from experimental/FE ones. This suggested modification of Wu model. Modified Wu's model which gives a better estimate for the ultimate load of Steel-Carbon Fibre Reinforced Polymer (SCFRP) composite specimen is presented in this paper.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.11a
• /
• pp.61-65
• /
• 2005

Existing test methods for thick-section specimens ( 4mm) have not provided precise compressive properties to date for the analysis and design of thick structure. A survey of the failure behaviour of such thick specimens revealed that the failure initiated at the top corner of the specimen and propagated down and across the width of the specimen as premature failure, not typically reported for thin compression specimens. In the current study, the premature failure was successfully avoided during compressive testing and the failure mode was quite similar regardless of increasing specimen thickness and specimen volume. Failure mode was similar regardless of increasing specimen thickness and specimen volume, i.e. brooming failure mode combined with longitudinal splitting, interlaminar cracking, fibre breakage and kinkband formation (fibre microbuckling). Nevertheless, average failure strengths of the specimens decreased with increasing specimen thicnkiness from 2mm to 8mm with the T800/924C system (36% strength reduction) and specimen volumes from scaling factor I to scaling factor 4 with the IM7/8552 system (46% strength reduction). It was revealed from the literature$^{11}$ that the thickness effect and scaling effect arc caused by manufacturing defects such as void content and fibre waviness.

• Steel and Composite Structures
• /
• v.1 no.1
• /
• pp.33-50
• /
• 2001

In this paper an experimental study is performed on end-plate type joints. The test arrangement represents a column-base joint of a steel frame. Altogether six specimens were tested, each of them subjected to cyclic loading. The specimens were carefully designed by performing detailed preliminary calculations so that they would present typical behaviour types of end-plate joints. On the basis of the experimentally established moment-rotation relationship, the cyclic characteristics of each specimen have been calculated and compared to one another. The results are evaluated, qualitative and quantitative conclusions are drawn.

• Geotechnical Engineering
• /
• v.5 no.2
• /
• pp.57-77
• /
• 1989

This paper describes the design and construction aspects of time-dependent deformation test apparatus for slut.oiling rocks and presents the test results obtained using these apparatus. These tests are modified semi-confined swell test, swell test under uniaxial tension and swell test under biaxial stress. These apparatus measure the time.dependent deformations in three orthogonal directions of the test specimen under simplified field stress conditions. The test results obtained from these test apparatus for the last several years show that these apparatus have performed satisfactorily. The test results show that the time-dependent deformation behaviour of the Queenston shale is cross-anisotropic with higher swelling in the vertical direction (normal to bedding plane) than in horizontal direction (parallel to bedding plane) under free swell condition. The applied stress in one direction suppresses the swelling deformation in that direction as well as that in the orthogonal directions.

• Journal of Mechanical Science and Technology
• /
• v.14 no.2
• /
• pp.152-158
• /
• 2000

The contents of this paper include the evaluation of corrosion characteristics and the behaviour of stress corrosion cracking (SCC) for the weldment and post weld heat treatment (PWHT) specimen and parent of HT -60 steel using a slow strain rate test (SSRT) in synthetic seawater. Corrosion characteristics were obtained from the polarization curves by potentiostat, and SCC phenomena were evaluated through the parameters such as reduction of area and time to failure by comparing the experimental results in corrosive environment with those obtained in air. Corrosion rate of the weldment was the fastest, followed by parent and PWHT specimen. SCC phenomena between the weldment of HT-60 steel and synthetic seawater were shown. Besides, SCC was dependent upon the pulling speed greatly. Maximum severity of SCC was obtained at a speed of $10^{-6}mm/min$, whereas SCC could not be seen almost at $10^{-4}mm/min$. The resistance to SCC for PWHT specimen was improved considerably compared that of the weldment at $10^{-6}mm/min$. In case of SCC failure, it was verified from SEM examination that brittle mode and lots of pits could be seen at the fractured region near the surface of the specimen.