Increase of bending strength and maximum deflection of concrete reinforced with CFRP strips

2011 ◽  
Vol 18 (1-2) ◽  
pp. 93-97
Author(s):  
Goichi Ben ◽  
Kazuhiro Sakata ◽  
Kazuma Saito
Keyword(s):  
High Performance ◽  
Bending Strength ◽  
Concrete Beams ◽  
Beam Theory ◽  
Design Criterion ◽  
Test Method ◽  
Bending Test ◽  
Plastic Behavior ◽  
Four Point Bending ◽  
Miyagi Prefecture

AbstractIn 1981, many detached houses collapsed owing to the earthquake which took place at the coast of Miyagi Prefecture in Japan, because ferroconcrete was not used as the base of most of the collapsed houses. Therefore, the earthquake-proof design criterion was revised and it was obliged to use ferroconcrete as the base of detached houses ever since. However, there are still more than 10 million detached houses using aged concrete as the base in Japan. In this paper, a reinforcement method for the aged concrete is demonstrated by using the high performance carbon fiber reinforced plastic (CFRP) strips. Three kinds of concrete beams reinforced with the CFRP strips with different vertical insert positions and different numbers of the CFRP strips were tested by a four point bending test method. In order to clarify the effects of CFRP strips, a concrete beam without reinforcement was also tested. The results of the experiment showed that the maximum deflections of the concrete beams reinforced with the CFRP strip were more than 100 times larger than those of the concrete beams without reinforcement. Although the concrete beams without the CFRP strips collapsed instantly, the concrete beams reinforced with the CFRP strips gradually failed, which were similar to the plastic behavior of metals. This result means that the residents can afford to escape safely from the houses in the event of possible earthquakes. The experimental results were compared with the analytical ones obtained from the composite beam theory and the failure criterion. Both results showed good agreement and the effectiveness of base concrete reinforced with CFRP strips was demonstrated.

Research on Damage and Bending Properties of AZ31 Magnesium Alloy

2012 ◽  
Vol 184-185 ◽  
pp. 1163-1166
Author(s):  
Xi An Xie ◽  
Gao Feng Quan
Keyword(s):  
Magnesium Alloy ◽  
Applied Load ◽  
Bending Strength ◽  
Az31 Magnesium Alloy ◽  
Bending Test ◽  
Bending Properties ◽  
Four Point Bending ◽  
Heat Treated ◽  
Four Point Bending Test ◽  
Initial Cracks

Through the four-point bending test of lath-shaped heat treated AZ31 magnesium alloy, the bending properties and damage characteristics were explored. The results show that the optimal bending strength of the magnesium alloy were 355.1MPa and 259.2MPa for extruded and cast samples, respectively, after corresponding heat treatment with 350°C, 90min and 400°C, 30min. The initial cracks both occurred at the loading point after applied load exceeded the yield limit of AZ31 magnesium alloy. Surface bump, cracks and other damage morphology accompanied by a large number of twinning organizations were found on the surface of the samples.

Study on the Creep Properties of Resin Concrete

2014 ◽  
Vol 472 ◽  
pp. 649-653
Author(s):  
Hui Cun Shen ◽  
Kui Tian ◽  
Yan Hua Hu
Keyword(s):  
Dynamic Stiffness ◽  
Structure Design ◽  
Test Method ◽  
Bending Test ◽  
Creep Properties ◽  
Four Point Bending ◽  
Long Term Effect ◽  
Urgent Task ◽  
Machined Parts ◽  
New Material

Resin concrete is a new material which can be made into machine bed instead of the traditional pieces of gray cast iron as the machine base, it can improve the dynamic stiffness of machine tools and the quality of machined parts, and extend the campaign life, reduce noise and improve efficiency. However, due to the long-term effect of load of the resin concrete, the elastic deformation occurs in its component, and the strain will increase over time. Thus it can affect the resin concretes service life, and the calculation of creep has become an urgent task in structure design and use, which should be taken seriously. In this paper, the bending creep properties of resin concrete beam were studied and analyzed by using four-point bending test method. The creep curve under different load levels were obtained, and the viscoelastic properties were analyzed.

Bending Strength of Cast Materials Reinforced with Hard Particles

2010 ◽  
Vol 457 ◽  
pp. 404-409
Author(s):  
Setsuo Aso ◽  
Hiroyuki Ike ◽  
Ken-Ichi Ohguchi ◽  
Yoshinari Komastu ◽  
Nobuo Konishi
Keyword(s):  
Composite Material ◽  
Bending Strength ◽  
Composite Layer ◽  
Cemented Carbide ◽  
Bending Test ◽  
Spheroidal Graphite ◽  
Four Point Bending ◽  
Hard Particles ◽  
Particle Reinforced Composite ◽  
Insertion Process

Particle reinforcement via the insertion of hard particles is a promising process in materials reinforcing. Particle-reinforced spheroidal graphite martensitic cast iron (SGMC), in which mixed particles of cermet and cemented carbide are dispersed, was achieved by an insertion process. A four-point bending strength test was applied to evaluate the particle composite material. An evaporative pattern process was used on the bending-test specimen to form a composite layer in the central part. Using a combination of three sizes of cermet particles and two sizes of cemented-carbide particles, the bending strength was found to increase with each small-particle combination. The Weibull coefficient m of the four-point bending strength of the particle-reinforced composite material (PRCM) ranged from 4 to 13, and m was large in the specimen with large bending strength.

scholarly journals Investigation of Interlaminar Defects and their Influence on Interlaminar Strength

1996 ◽  
Vol 5 (4) ◽  
pp. 096369359600500
Author(s):  
J Ziao ◽  
J Tao
Keyword(s):  
Tensile Strength ◽  
Large Scale ◽  
Peel Strength ◽  
Test Method ◽  
Bending Test ◽  
Four Point Bending ◽  
Transverse Tensile ◽  
Interlaminar Shear ◽  
Transverse Tensile Strength ◽  
Set Up

In this paper, we directed our attention to the interlaminar defects and their influence on the interlaminar strengths. With the aid of a S-570 scanning electron microscope, the morphology and distribution of interlaminar defects were inspected and documented. According to their shape, size and cause of formation, the defects were classified into five types: flakiness void, irregular shaped debond, local imperfectly cured resin, debond in two multi-directional plies, and inhomogeneous fibers and the large scale debond by these fibers. The cause of defects formation was discussed by analyzing the manufacturing process of composites. The influence of defects on the interlaminar strength and its mechanism was analyzed experimentally and theoretically. The results indicate that these defects, with different effects, decrease the interlaminar strength because they form interlaminar cracks, and the interlaminar shear strength is less affected than interlaminar tensile strength, which is measured according to GB4944 test method. To comprehend defects distribution effect, a four-point-bending test method was introduced to measure the interlaminar peel strength, and a discussion was made on the correlation between the interlaminar tensile strength, interlaminar peel strength and in-plane transverse tensile strength. Finally the concept of interlaminar defect coefficient, which can be used to characterize the defects, was set up and the formula to calculate it was proposed.

Study of Metallurgy and Mechanical Property on Japanese Sword

2013 ◽  
Vol 738-739 ◽  
pp. 222-227 ◽  
Author(s):  
Muneo Yaso ◽  
Yoshihiro Minagi ◽  
Toshifumi Takaiwa ◽  
Kunichika Kubota ◽  
Tsuyoshi Kanaizumi ◽  
...  
Keyword(s):  
Grain Size ◽  
Cross Section ◽  
High Performance ◽  
Bending Strength ◽  
Lath Martensite ◽  
Bending Test ◽  
Sharp Edge ◽  
Tool Steels ◽  
The Difference ◽  
The Ideal

Japanese sword has finer grain size and lath martensite in the microstructure of sharp edge amazingly. Nowadays these structures are considered to be one of the ideal structure at which are greatly aimed to strengthen or improve toughness of steels. Though the carbon content of its sharp edge is 0.70 mass %, there are no lenticular martensite and no micocracking in that area. As a result of bending test by actual sword specimen, one sword was finally bent, the other sword was broken. However it is found the sharp edge in Japanese sword has such a large bending strength 2500, 4600MPa respectively as modern, high performance tool steels and the difference of crack propagation under bending depends on the microstructure distribution and the grain size in cross section of Japanese sword.

Study on the Flexural Property of PVA-High Toughness Cementitious Composites

2011 ◽  
Vol 250-253 ◽  
pp. 765-768
Author(s):  
Wen Ling Tian ◽  
Lei Xu ◽  
Xiao Wei Wang
Keyword(s):  
High Performance ◽  
Tensile Elongation ◽  
Bending Test ◽  
Uniaxial Tensile ◽  
Cementitious Composites ◽  
Flexural Property ◽  
Uniaxial Tensile Test ◽  
Normal Concrete ◽  
Flexural Performance ◽  
Four Point Bending

For the compressive strength of the normal concrete is high and the tensile strength is low, it is typically brittle material. The ultimate tensile elongation of it is insufficiently 1/1000. Zhongwei Wu, an academician of Chinese Academy of Engineering pointed out that compounding cementitious composites was the way to make it high-performance, and fiber reinforced was the key[1]. Polyvinyl Alcohol Engineered Cementitious Composites has super flexural performance[2] and stretching ability[3],and its ultimate deflection is approximately 40 times larger than that of normal concrete when bended, similar to the multiple cracking and super toughness of uniaxial tensile test, it shows significant bending hardening behavior in the process of the test. This paper studied its flexural property by four point bending test .

scholarly journals Structural Behavior of High Strength Laced Reinforced Concrete One Way Slab Exposed to Fire Flame

2019 ◽  
Vol 5 (12) ◽  
pp. 2747-2761
Author(s):  
Anas Ibrahim Abdullah
Keyword(s):  
Reinforced Concrete ◽  
Bending Strength ◽  
High Strength ◽  
Bending Test ◽  
Structural Members ◽  
Four Point Bending ◽  
Steady State Temperature ◽  
Average Residual ◽  
Fire Flame ◽  
Geometric Layout

In this study, an experimental investigation had conducted for six high strength laced reinforced concrete one-way slabs to discover the behavior of laced structural members after being exposed to fire flame (high temperature). Self-compacted concrete (SCC) had used to achieve easy casting and high strength concrete. All the adopted specimens were identical in their compressive strength of ( , geometric layout 2000 750 150 mm and reinforcement specifics except those of lacing steel content, three ratios of laced steel reinforcement of (0.0021, 0.0040 and 0.0060) were adopted. Three specimens were fired with a steady state temperature of  for two hours duration and then after the specimens were cooled suddenly by spraying water. The simply supported slabs were tested for flexure behavior with two line loads applied in the middle third of the slab (four-point bending test). The average residual percentage of cubic compression strength and splitting tensile strength were 57.5% and 50% respectively. The outcomes indicated that the residual bending strength of the burned slabs with laced ratios (0.0021, 0.004, 0.006) were (72.56, 70.54 and 70.82%) respectively. However; an increase in the deflection was gained to be (11.34, 14.67 and 17.22%) respectively with respect to non-burned specimens.

Production of the Test Timber-UHPC Composite Bridge

2021 ◽  
Vol 322 ◽  
pp. 157-162
Author(s):  
Milan Holý ◽  
David Čítek ◽  
Petr Tej ◽  
Lukáš Vráblík
Keyword(s):  
Composite Structure ◽  
High Performance ◽  
Bridge Deck ◽  
High Performance Concrete ◽  
Test Structure ◽  
Load Test ◽  
Bending Test ◽  
Experimental Development ◽  
Four Point Bending ◽  
Composite Bridge

This article presents the results of the experimental development of a unique bridge system consisting of timber beams connected with bridge deck segments made of Ultra-High Performance Concrete (UHPC). The article deals with the production of a full-scale prototype of the timber-concrete composite structure and with an execution of a subsequent load test. The test structure was 3.30 m wide and 10.24 m long and was designed as two beams made of glue laminated timber connected with subtle bridge deck segments with a thickness only 60 mm and with a typical length of 1.50 m. The aim of the production of the test structure was to check some production details and procedures and subsequently to verify the behavior of the composite structure under load by the load test. The load test was performed with a theoretical span of 9.50 m as a four-point bending test to failure. After the overall load test was done, some bridge deck segments were cut from the structure and a load test of the bridge deck in transversal direction were executed to verify the behavior and the load-bearing capacity of the bridge deck segments made of UHPC.

Waste size and lay up sequence strategy for reusing/recycling carbon fiber fabric in laminate composite: Mechanical property analysis

2021 ◽  
pp. 002199832110370
Author(s):  
Marcos Yutaka Shiino ◽  
Thais Carolina Gonçalves Cipó ◽  
Maurício Vicente Donadon ◽  
Alexei Essiptchouk
Keyword(s):  
Carbon Fiber ◽  
Mechanical Strength ◽  
Composite Structures ◽  
Bending Strength ◽  
Woven Fabrics ◽  
Bending Test ◽  
Four Point Bending ◽  
A Value ◽  
Strength Based ◽  
Pet Film

Carbon fiber fabrics have been largely used in composite structures as they provide high mechanical strength and potential weigh reduction, allowing more efficiency in product design. However, the production of the parts generates scraps that is discarded as a waste, becoming a challenge to recycle the carbon fiber with predictable mechanical strength. Within this context, this research analyzed strategies of laying up carbon woven fabrics based scraps, in order to reach a desirable mechanical properties in bending loading. Three types of laminates were manufactured using varied fabric size and number of discontinuities in the layup combined with polyethylene terephthalate (PET) film as a matrix. The obtained composites were tested under four-point-bending test and an energy-strength based analysis was conducted. This analysis explained a strategic position of fabric scrap to maximize the bending strength: providing a value of 106.33 MPa for a composite with high number of discontinuities against 83.11 MPa for another with less discontinuity.

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