Fatigue of Cord—Rubber Composites: II. Strain-Based Failure Criteria

1998 ◽  
Vol 71 (5) ◽  
pp. 866-888 ◽  
Author(s):  
B. L. Lee ◽  
B. H. Ku ◽  
D. S. Liu ◽  
P. K. Hippo
Keyword(s):  
Fatigue Life ◽  
Carbon Black ◽  
Composite Laminates ◽  
Stress Amplitude ◽  
Low Frequency ◽  
Cyclic Strain ◽  
Rubber Composites ◽  
Dynamic Creep ◽  
Rubber Composite ◽  
The Matrix

Abstract Fatigue failure mechanisms under low-frequency loading and their dependence on the strain properties were assessed for the rubber matrix composite of bias aircraft tire carcass reinforced by nylon cords as well as two model rubber composites reinforced by steel wire cables. Under cyclic tension at constant stress amplitude, these angle-plied, cord—rubber composite laminates exhibited localized damage in the form of cord—matrix debonding, matrix cracking, and delamination. The process of fatigue damage accumulation in the cord—rubber composite laminate was accompanied by a steady increase of cyclic strain (dynamic creep) and moderate temperature changes. The fatigue life was found to be linearly proportional to the inverse of the dynamic creep rate, i.e., the time required to increase cyclic strain by a unit amount. Regardless of the associated level of stress amplitude or fatigue life, the gross failure under low-frequency loading occurred when the total strain accumulation, i.e., cumulative creep strain, reached the static failure strain. The use of higher stress amplitude resulted in a decrease of fatigue life by simply shortening the time to reach the critical level of strain for gross failure. This observation indicates that the damage initiation and eventual structural failure of angle-plied, cord—rubber composite laminates are “ strain-controlled” processes. These critical strain properties appear to be controlled by the process of interfacial failure between the cord and matrix. Under static tension, the strain levels for cord—matrix debonding and gross failure of composite laminates showed no significant dependence on the level of carbon black loading of the matrix compound, despite the fact that carbon black loading strongly affected the modulus, strength and strain properties of the matrix. Also the number of debonding sites around the cut ends of cords increased at almost the same rate as the static strain increased regardless of the variation of matrix properties.

Fatigue of Cord—Rubber Composites: III. Minimum Stress Effect

1998 ◽  
Vol 71 (5) ◽  
pp. 889-905 ◽  
Author(s):  
B. H. Ku ◽  
D. S. Liu ◽  
B. L. Lee
Keyword(s):  
Fatigue Life ◽  
Composite Laminates ◽  
Critical Level ◽  
Strain Range ◽  
Stress Range ◽  
Rubber Composites ◽  
Damage Potential ◽  
Damage Initiation ◽  
Rubber Composite ◽  
Minimum Stress

Abstract The dependence of fatigue lifetime on the minimum cyclic stress was assessed for the rubber matrix composite of bias aircraft tire carcass reinforced by nylon cords as well as two model rubber composites reinforced by steel wire cables. At a given stress range, the use of higher minimum stress up to a certain level led to longer fatigue life of the composite laminate. When the minimum stress exceeded this critical level, an opposite trend of shorter fatigue life occurred with a higher level of minimum stress. The initial trend of longer fatigue life of angle-plied, cord—rubber composite laminates with a higher level of minimum stress stems from a nonlinear stress—strain relationship with a tendency of strain stiffening. Under stress-controlled fatigue loading, a shorter strain range was experienced for the same stress range when the level of minimum stress was raised. However, the increase of minimum stress raises the potential for damage initiation and accumulation. This effect of increased damage potential became dominant above the critical level of minimum stress. When the fatigue life data were plotted against the values of strain range to clarify the role of damage potential, a general trend of shorter fatigue life with a higher level of minimum stress was observed at a given strain range, in striking contrast to the trend of the stress range vs the number of cycles to failure (S-N) curve in a conventional form. The result again confirms that the damage initiation and eventual fatigue failure of angle-plied, cord—rubber composite laminates are “strain-controlled” processes, as demonstrated in our preceding paper. A modified form of the Goodman equation appears to be valid in predicting the relationship between the strain range (instead of stress amplitude) and minimum strain (instead of mean stress) for a given lifetime of a cord—rubber composite laminate.

Orthogonal Experiment Analysis of Mechanical Thermal Conductivity on Multi-Component Fillers

2013 ◽  
Vol 753-755 ◽  
pp. 2379-2382
Author(s):  
Shi Meng Xu ◽  
Run Bo Ma ◽  
Jian Hua Du ◽  
Jun Hong Liu ◽  
Qi Jin
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Black ◽  
Orthogonal Experiment ◽  
Experiment Design ◽  
Rubber Composites ◽  
Orthogonal Experiment Design ◽  
Rubber Composite ◽  
Al Powder ◽  
Experiment Analysis

Filled the N330 carbon black, silica T80 carbon black and Al powder and Fe2O3 magnetic nanoparticles, the rubber composites on multi-component electromagnetic fillers were prepared according to orthogonal experiment analysis, and the preliminary experiment conclusions of the filler prescription designs were given; Based on the experiment design, the mechanical properties and thermal conductivity of the rubber composite were tested, and the testing results were analyzed by using variance analysis. Thus, the paper shows that the effects of N330 on rubber mechanical properties are significant, and the effects of Al powder on the rubber thermal conductivity are significant. Moreover, it is highly emphasized in this paper that the orthogonal experiment design must be carefully explored before the tests are executed.

scholarly journals The Preparation and Research on the Electromagnetic Shielding Effectiveness of T-ZnO@Ag/Silicone Rubber Composites

2019 ◽  
Vol 26 (2) ◽  
pp. 205-209 ◽  
Author(s):  
Jingkai NIE ◽  
Guangke WANG ◽  
Dong HOU ◽  
Fu GUO ◽  
Yu HAN
Keyword(s):  
Coating Layer ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Rubber Composites ◽  
Chemical Plating ◽  
Agno3 Solution ◽  
Rubber Composite ◽  
The Matrix ◽  
Micro Structures ◽  
Electromagnetic Shielding Effectiveness

This study first conducted surface modification of Ag-plated Tetrapod-like zinc oxide (T-ZnO) whiskers with the use of dopamine and prepared Ag-plated T-ZnO whiskers (T-ZnO@Ag) by means of chemical plating, in which AgNO3 solutions with different concentrations were used during the preparation. Micro-structures of the prepared T-ZnO@Ag powders were examined to evaluate the effect of AgNO3 concentration on Ag plating performance. Subsequently, conductive Si rubber samples were prepared, the T-ZnO@Ag powders were used as fillers, and the effectiveness of the related electromagnetic shielding was investigated in detail. The results showed that using AgNO3 solution with a concentration of 20 g/L, a continuous Ag coating-layer was observed on the surface of T-ZnO whiskers. It was evident that, when used as fillers, T-ZnO@Ag has a conductive threshold and when the mass fraction of the fillers exceeded 50 %, the T-ZnO@Ag whiskers that were uniformly dispersed in the matrix formed interconnected conductive paths. In this condition, the electromagnetic shielding effectiveness of the prepared T-ZnO@Ag/Si rubber composite reached up 90 dB.

Effects of Micro-Eggshells Filler on Tracking and Erosion Resistance of Silicone Rubber Composites

2020 ◽  
Vol 846 ◽  
pp. 37-41
Author(s):  
Pattarabordee Khaigunha ◽  
Tanakorn Wongwuttanasatian ◽  
Amnart Suksri
Keyword(s):  
Thermal Stability ◽  
Heat Resistance ◽  
Silicone Rubber ◽  
Erosion Resistance ◽  
Rubber Composites ◽  
Surface Tracking ◽  
Rubber Composite ◽  
The Matrix ◽  
Thermal Stability Of ◽  
Inclined Plane Test

This study investigates the effects of micron-sized eggshells filler on resistance to tracking and erosion of silicone rubber composite. Eggshells with particle size from 44 to 53 microns were filled into liquid room temperature vulcanizing (RTV) silicone rubber with 0, 5, 15, 25, and 30 part per hundred of rubber (phr). IEC-60587 inclined plane test (IPT) was employed to appraise the surface tracking resistance. Thermogravimetric analysis was conducted to evaluate its thermal stability. Experimental results revealed an improvement of tracking and erosion resistance due to an addition of eggshells particles. Furthermore, the thermal stability of the composites showed variation in the increasing amount of the filler. The filler indicated that higher thermal stability of eggshells influences the heat resistance of the matrix. An increase of the heat resistance resulted in the ability to slow down tracking growth and erosion in the discharge region.

Fatigue of Cord-Rubber Composites: V. Cord Reinforcement Effect

2004 ◽  
Vol 77 (4) ◽  
pp. 593-610 ◽  
Author(s):  
J. H. Song ◽  
F. Costanzo ◽  
B. L. Lee
Keyword(s):  
Shear Strain ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Failure Modes ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Temperature History ◽  
Rubber Matrix ◽  
Fatigue Lifetime ◽  
Dynamic Creep

Abstract Fatigue behavior of cord-rubber composite materials forming the belt region of radial pneumatic tires has been characterized to assess their dependence on stress, strain and temperature history as well as materials composition and construction. Estimated at various levels of stress amplitude were the fatigue life, the extent and rate of resultant strain increase (“dynamic creep”), cyclic strains at failure, and specimen temperature. Reflecting their matrix-dominated failure modes, such as cord-matrix debonding and delamination, composite laminates with different cord reinforcements showed the same S-N relationship as long as they were constructed with the same rubber matrix, the same cord angle, similar cord volume, and the same ply lay-up. The interply shear strain of 2-ply ‘tire belt’ composite laminate under circumferential tension was affected by twisting of specimen due to tension-bending coupling. However, a critical level of interply shear strain, which governs the gross failure of composite laminate due to the delamination, appeared to be independent of different lay-up of 2-ply vs symmetric 4-ply configuration. Because of much lower values of single cycle strength (in terms of gross fracture load per unit width), the composite laminates with larger cord angle and the 2-ply laminates exhibited exponentially shorter fatigue lifetime, at a given stress amplitude, than the composite laminates with smaller cord angle and 4-ply symmetric laminates, respectively. Maximum cyclic strain of composite laminates at failure, which measures the total strain accumulation for gross failure, was independent of stress amplitude and close to the level of static failure strain. For all composite laminates under study, a linear correlation could be established between the temperature rise rate and dynamic creep rate which was, in turn, inversely proportional to the fatigue lifetime.

scholarly journals Manifestation of Interactions of Nano-Silica in Silicone Rubber Investigated by Low-Frequency Dielectric Spectroscopy and Mechanical Tests

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 717 ◽  
Author(s):  
Chao Wu ◽  
Yanfeng Gao ◽  
Xidong Liang ◽  
Stanislaw M. Gubanski ◽  
Qian Wang ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Power Transmission ◽  
Mechanical Performance ◽  
Filler Content ◽  
Low Frequency ◽  
Mechanical Tests ◽  
Nano Silica ◽  
Rubber Composites ◽  
Rubber Composite ◽  
Surface Modified

Silicone rubber composites filled with nano-silica are currently widely used as high voltage insulating materials in power transmission and substation systems. We present a systematic study on the dielectric and mechanical performance of silicone rubber filled with surface modified and unmodified fumed nano-silica. The results indicate that the different interfaces between the silicone rubber and the two types of nano-silica introduce changes in their dielectric response when electrically stressed by a sinusoidal excitation in the frequency range of 10−4–1 Hz. The responses of pure silicone rubber and the composite filled with modified silica can be characterized by a paralleled combination of Maxwell-Wagner-Sillars interface polarization and DC conduction. In contrast, the silicone rubber composite with the unmodified nano-silica exhibits a quasi-DC (Q-DC) transport process. The mechanical properties of the composites (represented by their stress-strain characteristics) reveal an improvement in the mechanical strength with increasing filler content. Moreover, the strain level of the composite with a modified filler is improved.

Numerical Simulation for Mechanical Behavior of Carbon Black Filled Rubber Composites Based on Cubic Representative Volume Element

2014 ◽  
Vol 627 ◽  
pp. 285-288
Author(s):  
Qing Li ◽  
Xiao Xiang Yang
Keyword(s):  
Carbon Black ◽  
Representative Volume Element ◽  
Filler Content ◽  
Numerical Models ◽  
Volume Element ◽  
Experimental Results ◽  
Rubber Composites ◽  
Strain Behavior ◽  
Filled Rubber ◽  
Rubber Composite

Based on the connection between macroscopic and microscopic characteristics of carbon black filled rubber composites, Representative Volume Element (RVE) containing one single particle has been proposed, and three dimensional cubic RVE has been established to study and analyze the macroscopic mechanical properties of the carbon black filled rubber composites by the micromechanical finite element method. The research shows that the stiffness of the composite is increased with the increase of the volume fraction of carbon black filler particles. By comparison, it is shown that the results of the predictions on the stress-strain behavior of the rubber composite made with the cubic RVE numerical models containing one spherical particle are in good agreement with the experimental results for seven and fifteen percent carbon black filler content, but there is some discrepancy between them for twenty-five percent carbon black filler content. The results of the predictions on the stress-strain behavior of the rubber composite made with the cubic RVE numerical models containing one cubical particle are higher than the experimental results, and the higher the carbon black filler content, the greater is the discrepancy between them.

The Effect of Carbon Black Parameters on the Fatigue Life of Filled Rubber Compounds

1974 ◽  
Vol 47 (1) ◽  
pp. 231-249 ◽  
Author(s):  
E. S. Dizon ◽  
A. E. Hicks ◽  
V. E. Chirico
Keyword(s):  
Fatigue Life ◽  
Carbon Black ◽  
Carbon Black Particle ◽  
Chemical Action ◽  
Beneficial Effects ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
The Matrix ◽  
Black Particle ◽  
As Stress

Abstract Fatigue is defined as decay caused by cyclic deformations at an amplitude less than necessary for fracture in one cycle. Such failures are initiated by flaws which act as stress concentrators. These flaws occur in the material either through mechanical or chemical action during service or through agglomeration of certain ingredients during mixing and fabrication. This paper deals with the latter process, where the nature and size of the flaws as well as the properties of the matrix are contingent on carbon black variables. Using the tearing energy concept of fatigue developed by Lake and Lindley, it was shown that the size of the flaw is primarily determined by carbon black particle size. On the other hand, the cut growth constant depends on carbon black structure. When translated to actual fatigue life using the Monsanto Fatigue-to-Failure Tester, these relationships mean that under constant strain conditions, compounds containing coarse carbons will have a significantly higher fatigue life than those with fine carbons. Under conditions of constant strain, higher structure carbons will impart a slight positive effect. However, under conditions of constant stress, the beneficial effects of structure become magnified. Other factors known to affect fatigue life were also considered. These are : set, stress relaxation, hysteretic energy dissipation, and flaw size distribution.

Enhancing the Piezoresistance Senstivity and Repeatability of Carbon Nanotube/Silicone Nanocomposites

2014 ◽  
Vol 590 ◽  
pp. 207-210
Author(s):  
Xiao Xiang Zhang ◽  
Long Ba
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Materials ◽  
Carbon Black ◽  
Silicone Rubber ◽  
Smart Materials ◽  
Biomedical Engineering ◽  
Rubber Composites ◽  
Rubber Composite ◽  
Percolation Network

The nanocomposites of carbon nanotube/polymer have been studied to explore their piezoresistance properties, which can be used as smart materials in the fields like biomedical engineering, robotic engineering, and advanced instrumentation. The differences in piezoresistance behavior of the previous studies were explained by the less uniformity of carbon nanotubes. To clarify the resistance versus deformation relations for carbon nanotube/silicone rubber composite materials, we have fabricated composite materials with various nanotube and carbon black contents. The measurements show that the resistance versus deformation sensitive range is depends on both the content of nanotube and carbon black, while the tiny variation of content of the carbon black affects largely the total piezoresistance sensitivity and repeatability. The experiment shows that adequate amount of carbon balck mixed with carbon nanotube can improve the piezoresistance repeatability. The deformation induced variation of the conducting percolation network shall be the dominating mechanism for the piezoresistance behavior of carbon nanotube/silicone rubber composites.

Monitoring of Failure Mechanisms in Fiber Reinforced Composites During Cryogenic Cooling by Acoustic Emission

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1763-1769 ◽  
Author(s):  
Nak Sam Choi ◽  
Sung Choong Woo ◽  
Tae Won Kim ◽  
Kyong Y. Rhee
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
Composite Laminates ◽  
Low Frequency ◽  
Cryogenic Cooling ◽  
Reinforced Composites ◽  
Frequency Bands ◽  
Initial Stage ◽  
The Matrix ◽  
Ae Signals

Microfractures in composite laminates during cryogenic cooling were monitored employing thermo-acoustic emission(AE). During the initial stage of cryogenic cooling, very strong AE signals with low and high frequency bands were dominantly detected showing a development of large cracks accompanying fiber breakages. After that, weak emissions with low frequency bands became prevalent indicating the propagation of microfractures in the matrix and/or fiber-matrix interface. It was concluded that the breakage of bridged-fibers hindering the macroscopic cracking in the initial stage might be the representative cryogenic damage of composite laminates.

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