Performance of four plastics in relation to bolt relaxation in a non-conducting rail joint

1972 ◽  
Vol 7 (3) ◽  
pp. 194-204
Author(s):  
A S Mitchell ◽  
D Mills ◽  
R Kitching
Keyword(s):  
Cyclic Loading ◽  
Polymeric Materials ◽  
Electrical Insulation ◽  
Effect Of Temperature ◽  
Relaxation Behaviour ◽  
Static Tests ◽  
Service Conditions

Experiments have been conducted to observe the relaxation behaviour of fishplate-bolted rail joints in which four different polymeric materials were used for electrical insulation. Static tests were conducted to study the effect of temperature and of different locking sequences for the bolts on a rig which simulated service conditions at a joint. The effect of cyclic loading was considered.

scholarly journals Bond Fatigue of TRC with Epoxy Impregnated Carbon Textiles

2019 ◽  
Vol 9 (10) ◽  
pp. 1980 ◽  
Author(s):  
Juliane Wagner ◽  
Manfred Curbach
Keyword(s):  
Cyclic Loading ◽  
Residual Strength ◽  
Negative Impact ◽  
Fatigue Behavior ◽  
Tensile Load ◽  
Textile Reinforced Concrete ◽  
Anchorage Length ◽  
Static Tests ◽  
Number Of Cycles ◽  
Bearing Behavior

For the economical construction of fatigue loaded structures with textile reinforced concrete (TRC), it is necessary to investigate the fatigue behavior of the materials. Since next to the tensile load-bearing behavior, the bond behavior of a material is crucial as well, the present paper deals with the bond fatigue of TRC with epoxy-impregnated carbon textiles. First, static tests are carried out to determine the sufficient anchorage length of the investigated material combination. Afterwards, the influence of cyclic loading on the necessary anchorage length, deformation, stiffness, and residual strength is investigated. The results of the cyclic tests are summarized in stress-number of cycles to failure (S-N) diagrams. In the end, it can be said that the cyclic loading has no negative impact on the necessary anchorage length. If specimens withstand the cyclic loading, there is no difference between their residual strength and the reference strength. The failure of specimens occurs only at high load levels, provided that the anchorage length is sufficient.

Durability of Embedded PZTs in Structural Health Monitoring Systems under Cyclic Loading

2014 ◽  
Vol 891-892 ◽  
pp. 1255-1260 ◽  
Author(s):  
Sanghyun Yoo ◽  
Akbar Afaghi Khatibi ◽  
Everson Kandare
Keyword(s):  
Cyclic Loading ◽  
Structural Health Monitoring ◽  
Lead Zirconate Titanate ◽  
Health Monitoring ◽  
Low Cycle Fatigue ◽  
Maintenance Cost ◽  
Clear Understanding ◽  
Structural Health ◽  
Service Conditions

Structural Health Monitoring (SHM) systems are developed to decrease the maintenance cost and increase the life of engineering structures by fundamentally changing the way structural inspections are performed. However, this important objective can only be achieved through the consistent and predictable performance of a SHM system under different service conditions. The capability of a Piezoelectric lead Zirconate Titanate (PZT)-based SHM system in detecting structural flaws strongly depends on the sensor signals as well as actuator performance. But service conditions can change the behaviour of transducers, raising questions about long term SHM system capability. Although having a clear understanding of the reliable sensor life is important for surface mounted systems, however, this is particularly critical for embedded sensors. This is due to the fact that opportunity for replacement of sensors exists for surface bonded transducers while for the embedded systems, sensor replacement is not straightforward. Therefore, knowledge of the long term behaviour of embedded-SHM systems is critical for their implementation. This paper reports a study on the degradation of embedded PZT transducers under cyclic loadings. Carbon/epoxy laminates with an embedded PZT were subjected to fatigue loading and their performance was monitored using Scanning Laser Vibrometery (SLV). The functionality of PZT transducers under sensing and actuating modes were studied. High and low cycle fatigue tests were performed to establish strain-voltage relationships which can be used to identify critical cyclic loading parameters (number of cycles and R value) under sensing and actuating modes.

scholarly journals Quasi-Static Tests of Hybrid Adhesive Bonds Based on Biological Reinforcement in the Form of Eggshell Microparticles

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1391 ◽  
Author(s):  
Viktor Kolář ◽  
Miroslav Müller ◽  
Rajesh Mishra ◽  
Anna Rudawska ◽  
Vladimír Šleger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cyclic Loading ◽  
Service Life ◽  
Adhesive Layer ◽  
Maximum Load ◽  
Adhesive Bonds ◽  
Static Tests ◽  
Static Test ◽  
The Matrix ◽  
Positive Effect

The paper is focused on the research of the cyclic loading of hybrid adhesive bonds based on eggshell microparticles in polymer composite. The aim of the research was to characterize the behavior of hybrid adhesive bonds with composite adhesive layer in quasi-static tests. An epoxy resin was used as the matrix and microparticles of eggshells were used as the filler. The adhesive bonds were exposed to cyclic loading and their service life and mechanical properties were evaluated. Testing was performed by 1000 cycles at 5–30% (165–989 N) and 5–70% (165–2307 N) of the maximum load of the filler-free bond in the static test. The results of the research show the importance of cyclic loading on the service life and mechanical properties of adhesive bonds. Quasi-static tests demonstrated significant differences between measured intervals of cyclic loading. All adhesive bonds resisted 1000 cycles of the quasi-static test with an interval loading 5–30%. The number of completed quasi-static tests with the interval loading 5–70% was significantly lower. The filler positively influenced the service life of adhesive bonds at a higher amount of quasi-static tests, i.e., the safety of adhesive bonds increased. The filler had a positive effect on adhesive bonds ABF2, where the strength significantly increased up to 20.26% at the loading of 5–30% against adhesive bonds ABF0. A viscoelasticity characteristic (creep) of the adhesive layer occurred at higher values of loading, i.e., between loading 5–70%. The viscoelasticity behavior did not occur at lower values of loading, i.e., between loading 5–30%.

Variation of Structural Capacity of Reinforced Concrete Slab Due to the Repeated Cyclic Loading Idealized for Thermal Load

2010 ◽  
Vol 452-453 ◽  
pp. 697-700
Author(s):  
Soo Yeon Seo ◽  
Seung Joe Yoon ◽  
Hyun Do Yoon
Keyword(s):  
Cyclic Loading ◽  
Concrete Slab ◽  
Weather Data ◽  
Effect Of Temperature ◽  
Reinforced Concrete Slab ◽  
Structural Capacity ◽  
Long Term Effect ◽  
Test Parameters ◽  
Rc Slabs

A variation of temperature by sunlight acting on a RC roof slab causes a change of stress in concrete since it expands during summer and is compressed during winter. This behavior repeats annually and affects structural capacity of member for both serviceability and ultimate level. In this paper, a variation of cyclic temperature loading is calculated by analyzing the weather data of Korea for 20 years. In addition, an experimental work is planned to find the long term effect of temperature change. Four RC slabs are made with same dimension. Test parameters are loading duration (10, 20, 30 years). Observation of stiffness variations according to cyclic loading duration shows that the serious stiffness drop happens after 10 year's cyclic loading at summer while after 30 year's loading at winter. From the failure test, maximum strength of specimen that experienced repeated preloading was approximately 12% less than standard specimen without any repeated preloading.

Effect of Temperature on Resilience

1947 ◽  
Vol 20 (4) ◽  
pp. 998-1019 ◽  
Author(s):  
L. Mullins
Keyword(s):  
Physical Properties ◽  
Forced Vibrations ◽  
Effect Of Temperature ◽  
Empirical Correlations ◽  
Absorption Data ◽  
Warm Up ◽  
Mechanical Parts ◽  
Wide Range ◽  
Service Behavior ◽  
Service Conditions

Abstract The recent use of rubber components in extremes of climate and under a variety of service conditions has drawn attention to the importance of the knowledge of the physical properties of rubber vulcanizates at temperatures other than normal; the dearth of such knowledge has been emphasized by the enforced replacement of natural rubber by synthetic rubbers having reduced resistance to cold. When designing mechanical parts, the engineer must know first the conditions under which the part will be required to operate and, second, the physical properties under these conditions of the materials to be used. In a recent review Riesing has given illustrations of the importance of such knowledge; in particular he has shown that rubber mountings in an automobile may well be subjected to temperatures as high as 80 to 100° C, and although rubber mountings normally warm up during their operation, they may commence to function at extremely low temperatures, while there is a limiting temperature below which they fail even to warm up. The first part of this paper gives the results of the measurement of rebound resilience on a number of vulcanizates over a wide range of temperatures. Resilience is one of the important physical properties of a rubber vulcanizate, and in designing parts for shock or energy absorption, data on the resilience of the material are essential; for such applications a material with a low resilience is required, but as the energy absorbed manifests itself in the form of heat, the temperature rise of the absorber may control the permissible value of the resilience. In many other applications it is necessary that the material should have a high resilience and so absorb little energy. The resilience is normally determined by measuring the rebound of a ball or pendulum after impact on a sample of rubber; various other methods have been used, involving, either measurement of the decay in amplitude of the damped free vibration which results when a sample is deformed and then released, or measurement of the energy loss during sustained forced vibrations. Unhappily, the results from one test do not always show great similarity to the results from another test and, as a result, the engineer has to relay on empirical correlations with resilience tests conducted in a particular way, or on service behavior. The second part of this paper gives the lines along which an investigation is being conducted to illuminate the significance of these dissimilarities. The measurement of resilience over a range of temperatures has an added importance, since it throws some light on the structure of the rubber and on the processes taking place during deformation. Recent papers which have just become available in this country show that there has been interest and activity in this field in Germany during the war years.

Soft Vulcanized Rubber. Effect of Temperature and Oxygen Pressure on Aging Rate

1937 ◽  
Vol 10 (2) ◽  
pp. 336-345
Author(s):  
J. H. Ingmanson ◽  
A. R. Kemp
Keyword(s):  
Oxygen Pressure ◽  
Mechanical Strain ◽  
Accelerated Aging ◽  
Effect Of Temperature ◽  
Aging Rate ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Cause Of Failure ◽  
Service Conditions ◽  
Oxidation Effect

Abstract IMPORTANT to the manufacturer and consumer of rubber goods are suitable accelerated aging tests for predicting readily the life of rubber articles under the variable storage and service conditions encountered. Since service conditions may involve the exposure of rubber to wide variations of temperature, light, and atmosphere under various types of mechanical strain, there is obviously need for a variety of tests, each designed to emphasize factors which are most important in any given set of service conditions. Since the primary cause of failure of soft vulcanized rubber in service is oxidation, emphasis has been placed on tests which accelerate the oxidation effect. The most widely adopted and generally satisfactory procedure of this type is the Bierer and Davis oxygen bomb method which involves heating the rubber under oxygen pressure. In Bierer and Davis' original publication (2), results were shown on the effect of increasing oxygen pressure in increments of 28.1 kg. up to 112.5 kg. per cm. on the aging of two different rubber compounds at the three temperatures, 50°, 60°, and 70° C. Their results showed that in some cases there was a uniform increase in aging rate with increased pressure and in other cases the rate increased rapidly up to a pressure of 28.7 kg. per sq. cm. but more slowly with further increases in pressure. In a later investigation (3) the same authors employed a pressure of 21.1 kg. per sq. cm. and 60° C. throughout. For the past ten years most laboratories have used an oxygen pressure of 21.1 kg. per sq. cm. and a temperature of 70° C., which may therefore be considered as standard.

Mechanical Characterization and Failure Analysis of ABS Material Submitted to Static Tests under the Effect of Temperature

2019 ◽  
Vol 820 ◽  
pp. 159-172
Author(s):  
Abderrazak En-Naji ◽  
Nadia Mouhib ◽  
Mohamed El Ghorba
Keyword(s):  
Amorphous Polymer ◽  
Acrylonitrile Butadiene Styrene ◽  
Tensile Tests ◽  
Effect Of Temperature ◽  
Uniaxial Tensile ◽  
Industrial Zone ◽  
Static Tests ◽  
Damage Process ◽  
The Moment ◽  
Experimental Values

In this work, we study the influence of temperature on the mechanical behavior of an amorphous polymer, acrylonitrile butadiene styrene "ABS", based on a series of uniaxial tensile tests on smooth specimens at different temperatures.The results obtained show that the failure of the studied material (ABS) depends strongly on the temperature. Indeed, two zones have been identified: industrial zone T<Tg and thermoforming zone T>Tg (Tg is the glass transition temperature of ABS material).In the industrial zone, we conducted a study of the experimental and theoretical damage via the model of the unified theory. The comparison showed a good agreement concerning the acceleration of the damage process as the temperature increases. In the thermoforming zone, we adopted the same methods to follow the process of flow as a function of the temperature increase. Likewise, we compared theoretical and experimental values which in turn showed a good match. Different stages have been determined in each separate zone, that allows to predict the moment of the critical damage or flow and therefore to intervene in time for a predictive maintenance.

scholarly journals Experimental Study on Cumulative Damage Behavior of Steel-Reinforced Concrete Columns

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Lianjie Jiang ◽  
Guoliang Bai
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Bearing Capacity ◽  
Ground Motions ◽  
Peak Load ◽  
Cumulative Damage ◽  
Stiffness Degradation ◽  
Static Tests ◽  
Steel Ratio ◽  
Energy Dissipation Capacity

The cumulative damage behavior of SRC columns under far-field long-period ground motions was simulated and studied by quasi-static tests with the same displacement for 10 times. Quasi-static tests of 8 SRC columns were conducted under the horizontal cyclic loading with the same displacement for 10 times or 3 times, and then the effects of steel ratio, stirrup ratio, axial compression ratio, and number of cyclic loading on the cumulative damage of SRC columns under the far-field long-period ground motions were studied. The results showed that the number of cyclic loading had little effect on the peak load of the specimens, but had a significant effect on the deformation capacity, stiffness degradation, and energy dissipation capacity. Compared with the specimens after 3 cycles, the displacement ductility coefficient of specimens after 10 cycles was reduced by about 20%–26%, the ultimate hysteresis energy dissipation was reduced by 35%–48%, while the stiffness degradation rate was accelerated. After the peak load, the cumulative damage caused by multiple cyclic loading with the same displacement was more significant, which aggravated the reduction of bearing capacity and stiffness degradation. The smaller the steel ratio and stirrup ratio, the larger the axial compression ratio, and the greater the reduction of the bearing capacity and stiffness of specimens. However, accumulated damage caused by multiple cyclic loading with the same displacement had a slight impact on the energy dissipation capacity. Increasing the steel ratio and stirrup ratio can effectively improve the deformation capacity and energy dissipation capacity of the specimens and reduce the bearing capacity and stiffness degradation caused by cumulative damage.

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