Evaluation of Impact Bending Strength of Ceramic Composites at Ultra-High Temperatures from 1500-2000 °C in Air

2013 ◽  
Vol 591 ◽  
pp. 145-149 ◽  
Author(s):  
De Tian Wan ◽  
Yi Wang Bao ◽  
Hua Zhao ◽  
Yuan Tian
Keyword(s):  
High Temperatures ◽  
Bending Strength ◽  
Impact Load ◽  
Ceramic Composites ◽  
Test Method ◽  
Bending Test ◽  
Dynamic Force ◽  
Maximal Load ◽  
Impact Bending ◽  
The Impact

In this work, a new and novel test method was developed to determine the impact bending strength of ceramic composites at ultra-high temperature from 1500-2000 °C in air. Three-point impact bending test was carried out through a SiC pressure head with a dynamic force sensor fixed on a slider and movable along a guide rail. The impact load was adjusted by different saving energy and the impact speed was lower than 0.5 m/s. The center of the sample was heated up to about 1500-2000°C by oxygen-assisted spray combustion. An impact load was put on the specimen and the impact force was recorded automatically. The impact bending strength can be calculated from the maximal load and the sample size. To check the availability and reliability for this method, several ceramics including SiC, ZrB2/SiC and C/C fiber reinforced composite without coating, were used as the testing samples. The results indicate that this method is a good and feasible method for evaluating the mechanical properties of the ceramic composite at ultra-high temperatures.

A New Method for Determining Strength and Fracture Toughness of Ceramic Materials in Air at 1500-2000 °C

2014 ◽  
Vol 633 ◽  
pp. 447-450 ◽  
Author(s):  
De Tian Wan ◽  
Yi Wang Bao ◽  
Yuan Tian ◽  
Yan Qiu ◽  
Hua Zhao
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperatures ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Ceramic Composites ◽  
Test Method ◽  
Sic Fiber ◽  
Bending Load ◽  
Ceramic Components

Evaluation of the mechanical properties at ultra-high temperatures for ceramic composites is necessary and important for the safety of designing the ceramic components. In this work, a new and novel test method named as local ultra-high temperature together with applied load method (LUHTAL), was developed to determine the tensile, compressive, bending strength and fracture toughness of ceramic composites. The four point bending load was conducted to measure the bending strength and fracture toughness of ceramic composites after the center of the sample was heated up to about 1500-2000°C by oxygen-assisted spray combustion. To check the availability and reliability for this method, typical ceramic materials including ZrB2/SiC and C/SiC fiber reinforced composite coated with Si, were used as the testing samples. It is indicated that this method is good and feasible for evaluating the mechanical properties of the ceramic composite at ultra-high temperatures in air.

The Resistance Tests of Glass-Cement Plates in High Temperatures

2013 ◽  
Vol 586 ◽  
pp. 182-185
Author(s):  
Michaela Kostelecká ◽  
Miroslav Vokáč ◽  
Daniel Dobiáš
Keyword(s):  
High Temperatures ◽  
Bending Strength ◽  
Precast Concrete ◽  
Point Of View ◽  
Test Method ◽  
Bending Test ◽  
Technical Requirements ◽  
Glass Fibre Reinforced ◽  
Reference Samples ◽  
Strength In Bending

The glass-cement plates have made great progress today. They extend the possibilities of technical requirements in solutions of complex structures. The higher aesthetic requirements are available with the plates and in another point of view they contribute significantly to economic aspect in construction. The article describes the tests of high temperatures resistances of glass-cement plates. The first part is focused on determining the values of tensile strength in bending for samples subjected to annealing at temperatures 200, 300, 400 and 500 ° C in endurance at the highest temperature level for 24 hours. The results will be compared with values obtained for the reference samples. The bending strength was performed according to the norm ČSN EN 1170-4 Precast concrete products - Test method for glass-fibre reinforced cement - Part 4: Measuring bending strength, "Simplified bending test" method. The mean strength in bending of reference samples was equal to 11.3 MPa. The strength is decreasing with temperature of firing and dependence is very closed to linear relationship with slope approx. 1.87 MPa per 100 °C. Furthermore, the thermal dilatometric analysis was performed on the plates in the temperatures till 540 °C in the second part.

scholarly journals The Spread of Corrosion in Cast Iron and its Effect on the Life Cycle of Transportation Vehicles

2017 ◽  
Vol 65 (2) ◽  
pp. 383-389 ◽  
Author(s):  
Tomáš Binar ◽  
Jiří Švarc ◽  
Petr Dostál ◽  
Michal Šustr ◽  
Jan Tippner
Keyword(s):  
Impact Strength ◽  
Fractographic Analysis ◽  
Bending Test ◽  
Material Surface ◽  
Bending Tests ◽  
Corrosion Tests ◽  
Fracture Surfaces ◽  
Impact Bending ◽  
Notch Impact Strength ◽  
The Impact

This article deals with the spread of corrosion in material at different exposure times, and its effect on the measured brittle fracture and notch impact strength under different temperature conditions. To assess the degradational effect of corrosion on the material characteristics represented by the measured impact strength, we conducted a fractographic analysis of fracture surfaces, the aim of which was to evaluate the spread of corrosion in the material. In the first part of the experiment, two corrosion tests are simulated with a duration time of 432 and 648 hours, to compare the degradation effect of corrosion on the notch impact strength, depending on the duration of the corrosion tests. The following part shows the results of the impact bending test, where the experiment was conducted in an area of reduced and increased temperatures. The final part summarizes the results of the fractographic analysis of sample fracture surfaces from the impact bending tests. Based on the measured the length of the corrosion cracks, we analyzed the sample at the notch and from the material surface after the impact bending test.

scholarly journals Influence of Site Conditions and Quality of Birch Wood on Its Properties and Utilization after Heat Treatment. Part I—Elastic and Strength Properties, Relationship to Water and Dimensional Stability

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 189 ◽  
Author(s):  
Vlastimil Borůvka ◽  
Roman Dudík ◽  
Aleš Zeidler ◽  
Tomáš Holeček
Keyword(s):  
Heat Treatment ◽  
Dimensional Stability ◽  
Bending Strength ◽  
Color Change ◽  
Untreated Wood ◽  
Strength Properties ◽  
Treatment Temperature ◽  
Impact Bending ◽  
The Impact

This work deals with the quality of birch (Betula pendula) wood from different sites and the impact of heat treatment on it. Two degrees of heat treatment were used, 170 °C and 190 °C. The resulting property values were compared with reference to untreated wood samples. These values were wood density, compressive strength, modulus of elasticity (MOE), bending strength (MOR), impact bending strength (toughness), hardness, swelling, limit of hygroscopicity, moisture content and color change. It was supposed that an increase in heat-treatment temperature could reduce strength properties and, adversely, lead to better shape and dimensional stability, which was confirmed by experiments. It was also shown that the properties of the wood before treatment affected their condition after heat treatment, and that the characteristic values and variability of birch properties from 4 sites, 8 stems totally, were reflected in the properties of the heat-treated wood. Values of static MOR were the exception, where the quality of the input wood was less significant at a higher temperature, and this was even more significant in impact bending strength, where it manifested at a lower temperature degree. Impact bending strength also proved to be significantly negatively affected by heat treatment, about 48% at 170 °C, and up to 67% at 190 °C. On the contrary, the most positive results were the MOE and hardness increases at 170 °C by about 30% and about 21%, respectively, with a decrease in swelling at 190 °C by about 31%. On the basis of color change and other ascertained properties, there is a possibility that, after suitable heat treatment, birch could replace other woods (e.g., beech) for certain specific purposes, particularly in the furniture industry.

Experimente Research of Filler-Bitumen Ratio Impact on Asphalt Mixture Performance

2013 ◽  
Vol 361-363 ◽  
pp. 1851-1856 ◽  
Author(s):  
Lin Cao
Keyword(s):  
Low Temperature ◽  
Bending Strength ◽  
Asphalt Mixture ◽  
Bending Test ◽  
Bending Strain ◽  
Cracking Performance ◽  
Beam Bending ◽  
Bending Failure ◽  
The Impact ◽  
Asphalt Mortar

AH-130 base asphalt graded according to the upper limit of AC-16 close gradation is selected in this paper to identify the impact of asphalt mortar of different filler-bitumen ratios on asphalt mixture’s road performance through small beam bending test at low temperature. And then bending failure energy, in substitute of bending strength, bending strain, is used to evaluate the anti-cracking performance of asphalt mixture at low temperature.

90 Degree Impact Simulation of Steel Wheel

2017 ◽  
Author(s):  
Qian Gao ◽  
Yingchun Shan ◽  
Xiandong Liu ◽  
Er Jiang
Keyword(s):  
Impact Test ◽  
Impact Load ◽  
Reference Method ◽  
Bending Test ◽  
Test Bed ◽  
The Road ◽  
Steel Wheel ◽  
Impact Simulation ◽  
Deformation State ◽  
The Impact

The wheel is one of the important safety components of the vehicle. So, it is required to pass the dynamic rotating bending test, the dynamic radial fatigue test and the impact test. The 90-degree impact test represents the driving performance of a vehicle when the vehicle drives through the road pits, or drives in other harsh conditions. As for the steel wheel, there are no mandatory requirements for the impact test. In recent years, some steel wheel enterprises bring up 90-degree impact test for steel wheels in order to ensure the quality of their products. In this paper, a finite element simulation model of the steel wheel impact test bed under the case of 90-degree was established according to an enterprise’s impact test requirement. The software “ABAQUS” was used to simulate the 90-degree impact test. A wheel / tire overall model was assembled, considering the impacts of tire inflation and the tire preloading process. Then the deformation state of the rim under 90-degree impact load was analyzed to predict whether it could pass the requirements of relevant impact test successfully. The results show that the steel wheel does not meet the requirements of the impact test, which makes it necessary to study the steel wheel’s impact test and optimize the structure of the rim. This paper also provides a reference method for the impact simulation of the steel wheel.

Impact Resistance of SM Joints Formed With ICA

2002 ◽  
Vol 124 (4) ◽  
pp. 374-378 ◽  
Author(s):  
C. M. Lawrence Wu ◽  
Robert K. Y. Li ◽  
N. H. Yeung
Keyword(s):  
Impact Damage ◽  
Impact Resistance ◽  
High Energy ◽  
Bending Test ◽  
Conductive Adhesives ◽  
Energy Impact ◽  
Split Hopkinson ◽  
Post Impact ◽  
Impact Bending ◽  
The Impact

Isotropic conductive adhesives (ICA) have been considered as replacement materials for lead-tin solder alloys. In this paper, the post-impact shear strength of ICA surface mount (SM) joints was obtained experimentally and compared with that of SM lead-tin joints. The dynamic impact energy was provided in the form of three-point bending on the PCB using equipment called the split Hopkinson bar. Strain rates of over 4000/s were used for the impact bending test. The action of impact bending was used to simulate the effect on the PCB and the interconnection as a result of high energy impact on an electronic equipment. Shear test was then performed to examine the change in strength of the ICA joints as a result of impact damage. It was found that the SM ICA joints failed due to impact at a strain rate just over 4000/s. Microstructural examination carried out using a scanning electron microscope revealed that the interface between the ICA and copper pad on the PCB was the weakest region of the joint.

Experimental Study on the Size Effect on Flexural Behavior of Larch Glulam Beams

2016 ◽  
Vol 847 ◽  
pp. 3-9 ◽  
Author(s):  
Xian Yan Zhou ◽  
Lei Cao ◽  
Dan Zeng
Keyword(s):  
Size Effect ◽  
Large Scale ◽  
Bending Strength ◽  
Weibull Model ◽  
Test Method ◽  
Flexural Behavior ◽  
Bending Test ◽  
Glulam Beam ◽  
Bending Modulus ◽  
Size Adjustment

At present, design values in codes and regulations are mainly based on test results of small size specimens, which are different from large-scale members used in practical engineering, therefore size adjustment coefficients are needed to be established. The four-point bending test method was adopted to investigate four groups of different sizes of Larch Glulam beams in their flexural behavior. Experiment data such as ultimate bearing capacity, deflection, strains and others are obtained, and the failure pattern and failure mechanism of bending members are analyzed. The research results indicate that the bending modulus of elasticity of Larch Glulam beam is not affected by the size. Bending strength of the Larch Glulam beam show a declining trend as the size of specimens increases, however, the ultimate bending moment increases. In addition, by means of a two-parameter Weibull model, a so-called size effect coefficient has been calculated by the slope method, thus providing a basis for the design and application of Larch Glulam beams.

Industrial Kiln Drying and its Effect on Microstructure, Impregnation and Properties of Scots Pine Timber Impregnated for Above Ground Use. Part 2. Effect of Drying on Microstructure and Some Mechanical Properties of Scots Pine Wood

Holzforschung ◽  
2002 ◽  
Vol 56 (4) ◽  
pp. 434-439 ◽  
Author(s):  
N. Terziev ◽  
G. Daniel
Keyword(s):  
High Temperature ◽  
Scots Pine ◽  
Bending Strength ◽  
Untreated Wood ◽  
Polymer Complex ◽  
Pine Wood ◽  
Kiln Drying ◽  
Bordered Pits ◽  
Impact Bending ◽  
The Impact

Summary Scots pine (Pinus sylvestris L.) planks were dried in industrial progressive, conventional batch and high temperature kilns. The timber was further impregnated in an industrial autoclave with three preservatives used for above ground use. Samples dried by the three test methods and control samples were thereafter processed for scanning electron microscopy observations. Small clear specimens were sawn for determination of impact bending strength, modulus of elasticity and rupture (MOE and MOR) and hardness. The high temperature dried wood (at 115 °C) was characterised by partially damaged apertures in some bordered pits and nano- (10–20 nm) and micro checks (1–2 μm) in the warty and S3 layers of the cell walls. It is probable that certain modifications in the structure of the wood polymer complex also occurred due to hemicellulose thermal degradation. The above-mentioned structural changes facilitated the penetration of the preservative during impregnation and its evacuation during the final stage of vacuum. The industrial progressive and conventional batch kiln drying had no visible effect on the microstructure of Scots pine wood. There was no critical reduction of the impact bending strength, hardness and MOE of the dried untreated wood regardless of the drying method. MOR was significantly decreased after the conventional kiln drying, but not following high temperature drying. Impregnation with Tanalith E and conventional batch kiln drying aggravated the MOE and MOR of the high temperature dried wood, but both MOE and MOR did not differ significantly from those of progressive and conventional batch kiln dried samples.

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