Stress Analysis of Adhesion Tests

1983 ◽  
Vol 56 (1) ◽  
pp. 252-269 ◽  
Author(s):  
R. A. Ridha ◽  
R. N. Crano
Keyword(s):  
Maximum Shear Stress ◽  
Shear Stresses ◽  
Rubber Compound ◽  
Friction Forces ◽  
Pullout Force ◽  
Considerable Advantage ◽  
Rubber Compounds ◽  
Steel Cords ◽  
Photoelastic Analysis ◽  
Pull Through

Abstract The ASTM D 2229-80 test specimen with a circular hole and a pad restriction was analyzed by 3D finite elements. Maximum shear stresses within the specimen are at the cord-rubber interface. Thus, failure is expected to initiate in the vicinity of the cord-rubber interface. This characteristic is similar to that seen in the MICA and TCAT tests; it represents an improvement over other pull-through tests including earlier ASTM tests. The computed tensile stresses normal to the cord indicate that friction forces will not be significant in this test (as they are in the TCAT test) and that debonding will propagate rapidly. In this regard, the D 2229-80 test is similar to the MICA test. Results of photoelastic analysis of the ASTM D 2229-80, MICA, and TCAT tests are in good agreement with the computed results. Maximum shear stress at the cord-rubber interface in the ASTM D 2229-80 test varies with the modulus of elasticity of the rubber. This variation becomes more pronounced with increasing rubber deformations (e.g., at higher loads and with softer rubber compounds). Thus, the cord pullout force will be dependent on the rubber modulus. From the above results we conclude the following: 1. The ASTM D 2229-80 test overcomes one of the serious drawbacks of earlier pull-through tests; failure is expected to initiate in the vicinity of the cord-rubber interface rather than elsewhere in the rubber. The new test's main deficiency is the dependence of the cord pullout force on the rubber modulus; in this regard, the MICA test offers a considerable advantage. 2. The ASTM D2229-80 test may be used in evaluating the adhesion of various steel cords embedded in a control rubber compound. 3. When changes are anticipated in the properties of the rubber compound, the MICA test offers a considerable advantage because the cord pullout force in the MICA test is independent of the rubber modulus.

Stress Analysis of Cord Adhesion Tests — A Route to Improved Tests

1981 ◽  
Vol 54 (4) ◽  
pp. 835-856 ◽  
Author(s):  
R. A. Ridha ◽  
J. F. Roach ◽  
D. E. Erickson ◽  
T. F. Reed
Keyword(s):  
Stress Analysis ◽  
Small Strain ◽  
Good Alternative ◽  
Strength Properties ◽  
Square Root ◽  
Rubber Compound ◽  
Adhesion Test ◽  
Pullout Force ◽  
Pull Through ◽  
Maximum Stresses

Abstract Stress fields were calculated in tire cord adhesion test specimens as a route to the development of improved wire adhesion tests. The calculated stresses were analyzed in order to predict the location of initiation of debonding and to assess the dependence of the cord pullout force on the modulus of the rubber compound. The computational results were validated by experiments on a variety of cord/rubber samples. Conclusions drawn from this study are as follows: The analyzed pull-through test for adhesion of steel wires has a serious drawback. Its major deficiency lies in the presence of a slot under the rubber block specimen. Maximum stresses are consistently higher at the slot edges than at the cord/rubber interface. This is responsible for: (a) initiation of failure at the slot edges rather than at the cord/rubber interface, (b) considerable rubber coverage, and (c) dependence of the cord pullout force on the strength properties of rubber. The test is more likely to test the strength of the rubber compound than it is to test the strength of adhesion. The TCAT test represents a significant improvement over the pull-through test with regard to the location of failure. Stresses at the cord/rubber interface are higher than elsewhere within the sample. Stresses along the cord show a high peak at the cord's embedded end. This highly localized peak initiates debonding at the embedded end and yields good reproducibility (failure is very unlikely to initiate elsewhere). Experiments on the TCAT specimen show a reproducibility of within 4.2%. Maximum stresses in the TCAT specimen vary with approximately the square root of the rubber modulus. Thus, while the TCAT may be an excellent choice for wire studies involving a single control compound, it may be limited when used in compounding studies and other tire applications which involve changes in the rubber properties. In such studies, the dependence on rubber modulus is viewed as a limitation of TCAT because: (a) unintentional changes in the rubber modulus will affect the cord pullout force and can lead to erroneous assessment of the adhesive strength, and (b) intentional changes in the rubber modulus cannot be simply factored out by a square root rule. Our experiments show that the exponent of the rubber modulus depends on how the modulus change is achieved. There are also many definitions of the modulus and several techniques for determining its value. Experiments on the SWAT test show a pullout force proportional to a lower exponent of the rubber modulus than the exponent in the TCAT test. Reproducibility is at 5.6%, i.e., somewhat poorer than the TCAT. The width of the sample, and the presence of cord reinforcements within that width (in addition to the cords being tested), are expected to change the stress distribution along the cords from the distribution in the TCAT test. The 9.5 mm × 9.5 mm steel-backed specimen represents a good alternative for adhesion tests in compounding studies and tire applications. Although its reproducibility is not as good as those of the TCAT and SWAT tests, its independence from the rubber properties and its ease of sample preparation make it a good alternative. Finite element stress analysis of adhesion tests can provide useful information for assessing alternative tests and developing improved tests. Although total cord pullout normally takes place after large deformations in the rubber, simplified, small strain material models can provide a good indication of the behavior of adhesion test specimens.

A critical look at the Wallace-Bott hypothesis in fault-slip analysis

2013 ◽  
Vol 184 (4-5) ◽  
pp. 299-306 ◽  
Author(s):  
Richard J. Lisle
Keyword(s):  
Shear Stress ◽  
Maximum Shear Stress ◽  
Fault Slip ◽  
Shear Stresses ◽  
Homogeneous State ◽  
Slip Direction ◽  
Fault Surface ◽  
State Of Stress ◽  
Simultaneous Movement

AbstractThe assumption is widely made that slip on faults occurs in the direction of maximum resolved shear stress, an assumption known as the Wallace-Bott hypothesis. This assumption is used to theoretically predict slip directions from known in situ stresses, and also as the basis of palaeostress inversion from fault-slip data. This paper examines different situations in relation to the appropriateness of this assumption. Firstly, it is shown that the magnitude of the shear stress resolved within a plane is a function with a poorly defined maximum direction, so that shear stress values greater than 90% of the maximum occur within a wide angular range (± 26°) degrees. The situation of simultaneous movement on pairs of faults requires slip on each fault to be parallel to their mutual line of intersection. However, the resolved shear stresses arising from a homogeneous state of stress do not accord with such a slip arrangement except in the case of pairs of perpendicular faults. Where fault surfaces are non-planar, the directions of resolved shear stress in general give, according to the Wallace-Bott hypothesis, a set of slip directions of rigid fault blocks, which is generally kinematically incompatible. Finally, a simple model of a corrugated fault suggests that any anisotropy of the shear strength of the fault such as that arising from fault surface topography, can lead to a significant angular difference between the directions of maximum shear stress and the slip direction.These findings have relevance to the design of procedures used to estimate palaeostresses and the amount of data required for this type of analysis.

Wire Adhesion Testing

1972 ◽  
Vol 45 (1) ◽  
pp. 16-25 ◽  
Author(s):  
L. C. Coates ◽  
C. Lauer
Keyword(s):  
Bond Strength ◽  
Physical Properties ◽  
Test Method ◽  
Material Strength ◽  
Basic Design ◽  
Rubber Compound ◽  
Reliable Test ◽  
Adhesion Testing ◽  
Rubber Compounds ◽  
The Relationship

Abstract The results of this study are conclusive. The ASTM D-2229 Test Method is not a reliable test for measuring adhesion of wire cords to rubber compounds. However, by using the basic design and modifying it, an accurate measurement of bond strength on a macroscopic level can be obtained. This test is insensitive for all practical purposes to compound physical properties and changes in cord diameter and embedded length—for both stranded and rod-like cords. It is also possible with this test to calculate the amount of stress that is exerted on the surface of the wire cord to determine the relationship between failing stress and the material strength of the rubber compound. Properly used, this new test should give the compounder a better tool to study the adhesion of compounds to metal.

scholarly journals Shear Stress Distribution in the Opening Chords of Hybrid R/C T-Beams with Opening

2018 ◽  
Vol 147 ◽  
pp. 01005
Author(s):  
Jonie Tanijaya
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Shear Force ◽  
Maximum Shear Stress ◽  
Shear Stress Distribution ◽  
Shear Stresses ◽  
Web Openings ◽  
The Right ◽  
Lower Corner ◽  
T Beam

This study is carried out to evaluate the potential of three hybrid T-beams with web openings theoretical shear stresses distribution. The shear stresses at the opening edges were plotted at the working stage, yielding stage and collapse stage for these three tested beams. The available experimental results from the previous research was compared to the finite element results as well as the developed analytical. The shear stress distribution at the middle of the top and bottom chords of the opening in pure bending region are zero. At the upper and lower corners of the opening occurs the maximum shear stresses. The maximum shear stress occurs at the right lower corner chord at the high moment edge and at the left upper corner chord at the low moment edge in beams with openings at high shear and high flexural – shear region. Furthermore, an extensive parametric study is performed on these beams to find the distributing ratio of the shear force between the opening chords. The shear force at an opening in hybrid R/C T-beam is carried by the top and bottom chords of the opening according to the area – moment of inertia root ratio with the correction factor 0.70.

Oxidation and Ozonation of Rubber

1985 ◽  
Vol 58 (3) ◽  
pp. 637-652 ◽  
Author(s):  
Robert W. Keller
Keyword(s):  
Short Review ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Systematic Development ◽  
Increasing Demand ◽  
Ozone Resistance

Abstract With the wide variety of elastomers, fillers, and other compounding ingredients available today, there is increasing demand for rubber compounds with specific properties. The systematic development of the desired rubber compound can be undermined by the exposure of the compound to oxygen and ozone during use. Thus, a rubber compounder should be aware of the effects of oxygen and ozone attack on rubber and how to compound for oxygen and ozone resistance. This short review is intended as an introduction to the phenomena of oxidation and ozonation of rubber.

Cyclic Deformation Behavior and Dislocation Substructures of Hexagonal Zircaloy-4 Under Out-of-Phase Loading

1999 ◽  
Vol 122 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Xiao Lin
Keyword(s):  
Phase Angle ◽  
Maximum Shear Stress ◽  
Equivalent Stress ◽  
Strain Range ◽  
Equivalent Strain ◽  
Mean Value ◽  
Shear Stresses ◽  
Phase Cycling ◽  
Variation Range ◽  
Additional Hardening

Macroscopic response and microscopic dislocation structures of Zr-4 subjected to biaxial fatigue under different phase angles of 30°, 60°, 90° and different equivalent strain ranges of 0.8%, 0.6%, 0.4% were studied. The testing results show that the delay angle between the stress deviators and strain increment tensors is strongly dependent on phase angle and the equivalent strain range. When phase angle equals 60°, the delay angle has the minimum variation range for all specimens. The mean value of the delay angle decreases with increasing phase angle or the equivalent strain range. The variation range and average value of the Mises equivalent stress have the maximum in S3 with the phase angle of 90°. They decrease as the equivalent strain range decreases. Zr-4 displays a pronounced initial hardening followed by a continuous softening for all specimens during out-of-phase cycling. The stabilized saturation stresses of Zr-4 under out-of-phase cycling are much higher than that under uniaxial cycling. It indicates that Zr-4 displays an obvious additional hardening. As the phase angle increases, the typical dislocation structure changes from dislocation cells to tangles. The dislocation-dislocation interactions increase resulting in an additional hardening. In essence, the degree of additional hardening depends, among other factors, on the maximum shear stress ratio of resolved shear stresses and critical resolved shear stresses (RSS/CRSS). [S0094-4289(00)00601-0]

Characterization of Snap-On Calf Nipple Product and Development of its Compound Formulation Based on Natural Rubber

2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Soxhlet Extraction ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rubber Component

This research aimed to develop the formulation of natural rubber filled with carbon black, silica and calcium carbonate for rubber calf nipple application. The reverse engineering was performed on the calf nipple product to analyze the rubber type and component by using Soxhlet extraction, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. Furthermore, mechanical properties were examined to act as benchmark for the rubber compound design. The results showed that rubber component in the nipple product was natural rubber, whereas two filler types revealed as carbon black and calcium carbonate with 10 and 35 of the total weight. In addition, rubber nipple showed the hardness of 46±1 Shore A and tensile strength of 5.3±0.60 MPa. From the investigation of the properties of developed rubber compounds in this work, it was found that the mechanical properties depended on type and content of filler. The required mechanical properties of vulcanizates were achieved at 20 phr of carbon black (N330), 20 phr of silica and 120 phr of calcium carbonate.

Fiber Adhesion to Rubber Compounds

2008 ◽  
Vol 81 (3) ◽  
pp. 523-540 ◽  
Author(s):  
W. B. Wennekes ◽  
R. N. Datta ◽  
J. W. M. Noordermeer ◽  
F. Elkink
Keyword(s):  
Plasma Treatment ◽  
Fiber Surface ◽  
Surface Roughening ◽  
Rubber Compound ◽  
Rubber Composites ◽  
Adhesion Promoter ◽  
Rubber Compounds ◽  
Polyester Fibers ◽  
History Of ◽  
Fiber Materials

Abstract The present paper provides an overview of literature published on fiber-rubber composites. A brief history of Fibers used in rubber applications is given. The emphasis is on the adhesion between fiber materials and rubber compounds. Special attention is given to the standard RFL-treatment and the double-dip treatment used for aramid and polyester Fibers to enhance the adhesion with rubber compounds. Some alternatives to the RFL-treatment are described: fiber surface roughening, adhesion promoter additives to the rubber compound, impregnated Fibers and plasma treatment.

Mechanical and Dynamic Properties of Silica-Filled Rubber Compounds

2013 ◽  
Vol 781-784 ◽  
pp. 475-478
Author(s):  
Watcharin Rassamee ◽  
Woothichai Thaijaroen ◽  
Thirawudh Pongprayoon
Keyword(s):  
Mechanical Properties ◽  
Dynamic Properties ◽  
Rolling Resistance ◽  
Rubber Compound ◽  
Cure Characteristics ◽  
Rubber Compounds ◽  
Silane Coupling ◽  
Unmodified Silica ◽  
Tan Δ ◽  
Wet Grip

Natural rubber compound using different silicas, including unmodified silica, admicellar-modified silica and silica with silane coupling agent, were studied. The properties including cure characteristics, mechanical properties and dynamic properties were examined with the comparison of three compounds. The results show that cure characteristics of admicellar silica/rubber compound (Ad-Si/R) was shorter than those of unmodified silica/rubber compound (Un-Si/R) and silane coupling silica/rubber compound (Sil-Si/R). Mechanical properties of Ad-Si/R and Sil-Si/R were better than those of Un-Si/R. In addition, wet grip and rolling resistance analyzed from tan δ (5 Hz) at 0°C and 60°C, respectively, by DMA were found that the wet grip of Ad-Si/R was the best, whereas the rolling resistance of Sil-Si/R was the best, in the comparison.

Tear Initiation and Tear Propagation

1950 ◽  
Vol 23 (1) ◽  
pp. 137-150 ◽  
Author(s):  
J. M. Buist
Keyword(s):  
Test Piece ◽  
Maximum Shear Stress ◽  
Test Group ◽  
Preliminary Evaluation ◽  
Discriminating Power ◽  
Rubber Compounds ◽  
Group 2 ◽  
Tear Propagation ◽  
Limiting Value ◽  
Group 1

Abstract (1) Both the crescent and angle tests are group (2) tests; therefore the width of the sample must fee taken into account when the tear resistance is being calculated. (2) There is one exception to the above, and that is the case of knotty tears in group (2) tests. When knotty tears occur, the test becomes a direct tear test [group (1)], and the width is no longer important. (3) When knotty tears occur with group (1) tests, the width must be considered for, in reality, the test has become a group (2) test. (4) Some rubbers exhibit fibering during tearing, and this is explained by the cohesive forces between fibers reaching a limiting value before the limiting value of the breaking strength of a fiber is reached. (5) Differences in the mechanism of tearing with different fillers have been noted. (6) Practical evidence of the existence of maximum shear stress in subsurface planes of the material has been obtained, and a mathematical solution for a simple case has been given. (7) The angle tear method is a combination of tear initiation and tear propagation, and can be regarded as complementary to the crescent test. It cannot be regarded as a replacement for the crescent test. (8) With certain rubber compounds the component of stress in the direction of pull is too high in the case of the angle test-piece. (9) It is suggested that the unnicked crescent be used in preference to the angle test-piece for tear initiation measurements, as the unnicked crescent test-piece has more discriminating power. (10) The same proportion of straight and knotty tears occurs with both the crescent and angle methods. (11) A preliminary evaluation of the I.G. tear cutter indicates that the fairest comparison with other methods requires a single slit to be inserted in the outside circumference of the ring.

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