scholarly journals Development of Energy-Dissipating Device for Rockfall and Debris-Flow Barriers

2020 ◽  
Vol 20 (6) ◽  
pp. 197-207
Author(s):  
Sanghoon Seo ◽  
MinHyong Choi
Keyword(s):  
Debris Flow ◽  
High Performance ◽  
Simulation Analysis ◽  
Tensile Force ◽  
Tensile Tests ◽  
Significant Component ◽  
Steel Bars ◽  
Frictional Forces ◽  
Ring Net ◽  
Energy Dissipating Device

In this study on the development of energy-dissipating devices, a significant component of the ring-net system was investigated for the localization of a high-performance rockfall fence and debris flow barriers. The energy-dissipating device was developed as a structure that dissipated the resistance and frictional forces generated by the pipe passing through two steel bars, and the tensile force was transmitted by utilizing the pipe deformation. The performance of the developed energy-dissipating device was verified through simulation analysis and tensile tests. It was confirmed that the most effective dissipating device was made of a D60.5-3.2t pipe subjected to a rolling interval of 40 mm, and the device exhibited an energy-dissipating performance of 52.8-60.2 kJ/m.

Research on the Influence of Artificial Ageing on the Tensile Properties of Plastic Coated Composites with Fabric Inserts, in the Presence of Simulated Welding Imperfections

2014 ◽  
Vol 1029 ◽  
pp. 224-229
Author(s):  
Lorand Kun ◽  
Alin Constantin Murariu
Keyword(s):  
Tensile Properties ◽  
High Performance ◽  
Cooling System ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uv Exposure ◽  
Clear Correlation ◽  
Artificial Ageing ◽  
Forced Cooling ◽  
Uv Lamps

An experimental research regarding the effects of artificial ageing by UV exposure on the tensile properties of a plastic coated composite material with fabric inserts, used mainly in the production of truck covers is presented in this paper. For the purpose of artificial ageing, the authors designed and built at ISIM Timisoara an original equipment with high performance UV lamps, adjustable geometry and forced cooling system. Defects of different sized were created in the aged and not aged specimens in order to simulate potential imperfections that appear during the joining process of these materials. The influence of artificial ageing with 24h and 48h exposure and imperfection size is highlighted by comparative analysis of the results obtained from the tensile tests that were carried out on all specimens. The results are further compared to the tensile properties of aged and not aged welded specimens, obtained using high frequency current and hot air welding methods. The results show clear correlation between the imperfection size and the maximum tensile force and the elongation at break respectively. It is concluded however that further testing is necessary in the specially built equipment in order to properly describe the effect of accelerated artificial ageing by UV exposure on the tensile properties of plastic coated composite materials with fabric inserts.

scholarly journals Chemical and physical interactions of regenerated cellulose yarns and isocyanate-based matrix systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bernhard Ungerer ◽  
Ulrich Müller ◽  
Antje Potthast ◽  
Enrique Herrero Acero ◽  
Stefan Veigel
Keyword(s):  
Mechanical Performance ◽  
Tensile Force ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Size Exclusion ◽  
Regenerated Cellulose ◽  
Hydrolytic Cleavage ◽  
Yarn Twist ◽  
Exclusion Chromatography ◽  
Physical And Chemical

AbstractIn the development of structural composites based on regenerated cellulose filaments, the physical and chemical interactions at the fibre-matrix interphase need to be fully understood. In the present study, continuous yarns and filaments of viscose (rayon) were treated with either polymeric diphenylmethane diisocyanate (pMDI) or a pMDI-based hardener for polyurethane resins. The effect of isocyanate treatment on mechanical yarn properties was evaluated in tensile tests. A significant decrease in tensile modulus, tensile force and elongation at break was found for treated samples. As revealed by size exclusion chromatography, isocyanate treatment resulted in a significantly reduced molecular weight of cellulose, presumably owing to hydrolytic cleavage caused by hydrochloric acid occurring as an impurity in pMDI. Yarn twist, fibre moisture content and, most significantly, the chemical composition of the isocyanate matrix were identified as critical process parameters strongly affecting the extent of reduction in mechanical performance. To cope with the problem of degradative reactions an additional step using calcium carbonate to trap hydrogen ions is proposed.

scholarly journals Experimental Investigation into Corrosion Effect on Mechanical Properties of High Strength Steel Bars under Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strength Steel ◽  
High Strength ◽  
Tensile Tests ◽  
Reinforcing Steel ◽  
Test Results ◽  
Cross Sectional ◽  
Steel Bars

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.

Integrated High-Performance Concrete Beams Reinforced with Hybrid BFRP and Steel Bars

2022 ◽  
Vol 148 (1) ◽  
Author(s):  
Xin Wang ◽  
Shui Liu ◽  
Yuwei Shi ◽  
Zhishen Wu ◽  
Weidong He
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
Steel Bars

Systematic Experimental Investigation of Dielectric Electroactive Polymers Using a Custom-Built Uniaxial Tensile Test Rig

2015 ◽  
Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Pure Shear ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Specimen Preparation ◽  
Testing Device ◽  
Test Results ◽  
Test Rig ◽  
Geometry Test

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.

Cyclic Bond Testing of Steel Bars in High-Performance Underwater Concrete

2014 ◽  
Vol 24 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Hector Bernardo ◽  
Miguel Ángel Vicente ◽  
Dorys Carmen González ◽  
Juan Fernando Martínez
Keyword(s):  
High Performance ◽  
Steel Bars ◽  
Underwater Concrete

Finite-Element Model of Impact Loading and Deformation of a Flexible Steel Ring-Net Debris-Flow Barrier

2020 ◽  
Vol 21 (3) ◽  
pp. 04020026
Author(s):  
Aliena M. Debelak ◽  
Christopher A. Bareither ◽  
Hussam Mahmoud
Keyword(s):  
Finite Element ◽  
Debris Flow ◽  
Finite Element Model ◽  
Impact Loading ◽  
Element Model ◽  
Ring Net

On Mechanical Properties of Dissimilar Friction Welded Steel Bars

2005 ◽  
Vol 297-300 ◽  
pp. 2831-2836 ◽  
Author(s):  
Seon Jin Kim ◽  
Yu Sik Kong ◽  
Yeong Sik Kim ◽  
Sang Woo Kwon
Keyword(s):  
Friction Welding ◽  
Tensile Tests ◽  
Welding Parameters ◽  
Base Metals ◽  
Visual Examination ◽  
Welded Steel ◽  
Bending Fatigue ◽  
Notched Specimens ◽  
Steel Bars ◽  
Molybdenum Steel

An experimental study of dissimilar friction welding was conducted using 15mm diameter solid bar in chrome molybdenum steel (SCM440) to carbon steel (S45C) not only to optimize the friction welding conditions, but also to investigate the fatigue performance. The main friction welding parameters were selected to endure good quality welds on the basis of visual examination, tensile tests, Vickers hardness surveys of the bond of area and HAZ, and microstructure investigations. In this study, the specimens were tested as welded. For fatigue strength, the notched specimens for the optimal conditions were rotary bending fatigue tested. The results were compared with S-N curves for the base metals.

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